S-1/A

As filed with the Securities and Exchange Commission on September 30, 2009

Registration No. 333-159580

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

Amendment No. 2 to

FORM S-1

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

AMERICAN DG ENERGY INC.

(Exact name of registrant as specified in its charter)

Delaware	1711	04-3569304
(State or other jurisdiction of	(Primary Standard Industrial	(I.R.S. Employer
incorporation or organization)	Classification Code Number)	Identification No.)

American DG Energy Inc.

45 First Avenue

Waltham, MA 02451

781-622-1120

(Address, including zip code, and telephone number,

including area code, of registrant’s principal executive offices)

	Copy to:
John N. Hatsopoulos	Edwin L. Miller Jr.
Chief Executive Officer	Sullivan & Worcester LLP
American DG Energy Inc.	One Post Office Square
45 First Avenue	Boston, MA 02109
Waltham, MA 02451	Tel: (617) 338-2800/Fax: (617) 338-2880
(781) 622-1120/Fax: (781) 622-1027
(Name, address, including zip code, and telephone number, including area code, of agent for service)

Approximate date of commencement of proposed sale to the public:

From time to time after this registration statement becomes effective

If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box: R

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company.

Large accelerated filer: ¨ Accelerated filer: ¨ Non-accelerated filer: ¨ Smaller reporting company: R

CALCULATION OF REGISTRATION FEE

Title of Each Class of Securities  to be Registered	Amount to be Registered 1		Proposed Maximum Offering Price		Proposed Maximum Aggregate Offering Price		Amount of Registration Fee 2,3
Common Stock		22,308,871	$	2.90	$	64,695,725	$	3,610

1 Pursuant to Rule 429(b) under the Securities Act, 2,000,000 unsold shares of common stock previously registered under registration statement No. 333-142008 beneficially owned by In Holdings Corp.are being carried forward to this registration statement. The shares being registered hereby consist of 17,496,966 outstanding shares, 4,761,905 shares issuable upon conversion of convertible securities and 50,000 shares issuable upon the exercise of warrants.

2 Estimated solely to calculate the registration fee in accordance with Rule 457 under the Securities Act. The fee paid with the registration statement as originally filed was based on the closing price of the common stock on the OTC Bulletin Board on May 28, 2009. An additional 2,201,263 shares are registered hereby. The fee for the incremental shares is based on the average of the high and low sales prices of the common stock on the OTC Bulletin Board on September 1, 2009.

3 $3,344 of the registration fee was paid with the original filing of this registration statement.

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

PROSPECTUS (Subject to Completion)

Dated September 30, 2009

PROSPECTUS

22,308,871 Shares of Common Stock

We are registering for resale pursuant to this prospectus shares of our outstanding common stock, shares issuable upon conversion of outstanding convertible debentures and shares issuable upon exercise of outstanding warrants, other than shares that may be sold without restriction pursuant to Rule 144.

Our common stock is quoted on the OTC Bulletin Board, or OTCBB, under the symbol “ADGE”. The last reported sale price of our common stock on September 29, 2009 was $2.96 per share.

Included in the aggregate number of shares are: 17,496,966 outstanding shares of common stock; 4,761,905 shares issuable upon conversion of outstanding convertible debentures, and 50,000 shares issuable upon exercise of warrants. The selling stockholders may sell all or a portion of their shares in the over-the-counter market at prices prevailing at the time of sale, or related to the market price at the time of sale, or they may otherwise sell their shares at negotiated prices. Our shares of common stock are traded in the Over-the-Counter Bulletin Board electronic quotation service.

We will not receive any of the proceeds from the offer and sale of the shares. If the warrants related to the shares of common stock offered for sale pursuant to this prospectus are exercised in full, we will receive aggregate proceeds from such exercises of $150,000. If the options related to the shares of common stock offered for sale pursuant to this prospectus are exercised in full, we will receive aggregate proceeds from such exercises of $202,000. If the rights to purchase shares of common stock pursuant to our private placement of July 24, 2009, are exercised in full, we will receive aggregate proceeds from such exercises of $5,155,818. We will pay the expenses of this offering.

Our business and an investment in our common stock involve significant risks.  You should refer to the factors described in the section called “Risk Factors” contained in our Annual Report on Form 10-K, page 10, for our 2008 fiscal year that has been incorporated by reference in this prospectus. See page 2 for the reference.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is September 30, 2009

TABLE OF CONTENTS

About this Prospectus	2
Incorporation by Reference	2
Where You Can Find More Information	3
Special Note Regarding Forward-Looking Statements	3
About the Company	4
Dividend Policy	4
Use of Proceeds	4
Determination of Offering Price and Market Data	4
Selling Stockholders	5
Plan of Distribution	10
Experts	10

ABOUT THIS PROSPECTUS

In this prospectus, references to the “company,” “we,” “us,” “our,” and “registrant” refer to American DG Energy Inc.

You should rely only on the information contained in this prospectus. We have not, and the selling stockholders have not, authorized anyone to provide you with information that is different. The selling stockholders are offering to sell and seeking offers to buy shares of our common stock only in jurisdictions where offers and sales are permitted. You should assume that the information appearing in this prospectus as well as the information we filed previously with the Securities and Exchange Commission, or SEC, and incorporated herein by reference is accurate only as of the date of the document containing the information.

INCORPORATION BY REFERENCE

We have filed the following documents with the SEC, which are incorporated herein by reference:

· The company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2008, filed with the SEC on March 20, 2009 (File No. 000-52294).

· The company’s Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2009, filed with the Commission on May 14, 2009 (Commission No. 000-52294).

· The company’s Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2009, filed with the Commission on August 14, 2009 (Commission No. 000-52294).

· The company’s current report on Form 8-K filed with the Commission on February 26, 2009 (Commission No. 000-52294).

· The company’s current report on Form 8-K filed with the Commission on March 4, 2009 (Commission No. 000-52294).

· The company’s current report on Form 8-K filed with the Commission on April 27, 2009 (Commission No. 000-52294).

· The company’s current report on Form 8-K filed with the Commission on May 14, 2009 (Commission No. 000-52294).

· The company’s current report on Form 8-K filed with the Commission on July 27, 2009 (Commission No. 000-52294).

· The company’s current report on Form 8-K filed with the Commission on August 12, 2009 (Commission No. 000-52294).

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· The company’s current report on Form 8-K filed with the Commission on September 2, 2009 (Commission No. 000-52294).

· The description of the Common Stock set forth in the company’s registration statement on Form 10-SB filed with the SEC under the Securities Exchange Act of 1934, or the Exchange Act, including any amendments or reports filed for the purpose of updating such description (File No. 000-52294)

· The company’s Proxy Statement for the company’s 2009 Annual Meeting of Stockholders, filed with the SEC on April 29, 2009.

WHERE YOU CAN FIND MORE INFORMATION

We are subject to the information reporting requirements of the Exchange Act, and accordingly we file annual, quarterly and current reports, proxy statements and other information with the SEC. Members of the public may read and copy any materials we file with the SEC at the SEC’s Public Reference Room located at 100 F Street, N.E., Washington, DC 20549. Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-800-SEC-0330.

In addition, we are required to file electronic versions of these materials with the SEC through the SEC’s database system called EDGAR. Copies of this registration statement and its exhibits, as well as of our annual reports, quarterly reports, proxy statements and other filings may be examined without charge by accessing the EDGAR database at www.sec.gov and on our own website at www.americandg.com. Our website is not a part of this prospectus.

We will provide without charge to each person, including any beneficial owner, to whom this prospectus is delivered, upon written or oral request of such person, a copy of any or all of the documents incorporated by reference in this prospectus. Exhibits to the filings will not be sent, however, unless those exhibits have been specifically incorporated by reference in this prospectus.

           Requests for such documents should be addressed in writing or by telephone to: Anthony S. Loumidis, Chief Financial Officer, American DG Energy Inc., 45 First Avenue, Waltham, MA 02451, Phone: (781) 622-1117.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference contain forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical fact, included in this prospectus regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects and plans and objectives of management are forward-looking statements. The words “anticipates,” “believes,” “estimates,” “expects,” “intends,” “may,” “plans,” “projects,” “will,” “would” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.

We have based these forward-looking statements on our current expectations and projections about future events.  Although we believe that the expectations underlying our forward-looking statements are reasonable, these expectations may prove to be incorrect, and all of these statements are subject to risks and uncertainties. Therefore, you should not place undue reliance on our forward-looking statements. We have included important risks and uncertainties in the cautionary statements included in this prospectus, particularly the section called “Risk Factors” incorporated by reference herein. We believe these risks and uncertainties could cause actual results or events to differ materially from the forward-looking statements that we make. Should one or more of these risks and uncertainties materialize, or should underlying assumptions, projections or expectations prove incorrect, actual results, performance or financial condition may vary materially and adversely from those anticipated, estimated or expected. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make. We do not assume any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

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ABOUT THE COMPANY

We distribute and operate on-site cogeneration systems that produce both electricity and heat. Our business is to own the equipment that we install at customers’ facilities and to sell the energy produced by these systems to the customers on a long-term contractual basis. We call this business the American DG Energy “On-Site Utility”.

We offer a range of cogeneration systems that are highly reliable and energy efficient. Our cogeneration systems produce electricity from an internal combustion engine driving a generator, while the heat from the engine and exhaust is recovered and typically used to produce heat and hot water for on-site processes. We also distribute and operate water chiller systems that operate in a similar manner, except that the engine’s power drives a large air-conditioning compressor while recovering heat for hot water. Cogeneration systems reduce the amount of electricity that the customer must purchase from the local utility and produce valuable heat and hot water for the site to use as required.

The company was incorporated as a Delaware corporation on July 24, 2001. American DG Energy operated as a subsidiary of American Distributed Generation Inc. since 2003, along with Tecogen Inc. In December 2005, American DG Energy merged with American Distributed Generation Inc., and the company then changed its name to American DG Energy Inc. Our principal executive offices are located at 45 First Avenue, Waltham, Massachusetts 02451.

DIVIDEND POLICY

We have never declared or paid any cash dividends on shares of our common stock. We currently intend to retain earnings, if any, to fund the development and growth of our business and do not anticipate paying cash dividends in the foreseeable future. Our payment of any future dividends will be at the discretion of our board of directors after taking into account various factors, including our financial condition, operating results, cash needs and growth plans.

USE OF PROCEEDS

We will not receive any of the proceeds from the offer and sale of the shares. If the warrants related to the shares of common stock offered for sale pursuant to this prospectus are exercised in full, we will receive aggregate proceeds from such exercises of $150,000. If the options related to the shares of common stock offered for sale pursuant to this prospectus are exercised in full, we will receive aggregate proceeds from such exercises of $202,000. If the rights to purchase shares of common stock pursuant to our private placement of July 24, 2009, are exercised in full, we will receive aggregate proceeds from such exercises of $5,155,818. The funds we will receive from the proceeds of exercises of options related to shares of common stock or rights to purchase shares of common stock pursuant to our private placement will be used for installation of additional energy systems and for general corporate purposes.

DETERMINATION OF OFFERING PRICE AND MARKET DATA

Offering Price

The selling stockholders may sell all or a portion of their shares in the over-the-counter market at prices prevailing at the time of sale, or related to the market price at the time of sale, or they may otherwise sell their shares at negotiated prices. We cannot determine what the actual offering price will be at the time of sale.

Market

Our common stock started trading on November 8, 2007 on the OTCBB under the symbol “ADGE”. OTCBB market quotations reflect inter-dealer prices, without retail mark-up, mark-down or commissions and may not necessarily represent actual transactions. During the period from November 8, 2007 to December 31, 2007, the high price was $1.25 and the low price was $0.83 as reported by the OTCBB. The following table sets forth the high and low per share sales prices for our common stock for each of the quarters in the period beginning January 1, 2008 through June 30, 2009 as reported by the OTCBB.

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Quarter Ended	High		Low
March 31, 2008	$	1.09	$	0.73
June 30, 2008	$	1.92	$	1.01
September 30, 2008	$	2.05	$	1.35
December 31, 2008	$	2.31	$	1.65
March 31, 2009	$	2.20	$	1.50
June 30, 2009	$	3.25	$	2.45

The closing price of our common stock as reported on the OTCBB on September 29, 2009 was $2.96.

Holders

As of September 2, 2009, there were approximately 90 holders of record of our common stock. As of September 2, 2009, there were approximately 348 beneficial holders of our common stock.

SELLING STOCKHOLDERS

We are registering for resale pursuant to this prospectus shares of our outstanding common stock, shares issuable upon conversion of outstanding convertible debentures and shares issuable upon conversion or exercise of our outstanding warrants. This prospectus does not cover shares that may be sold without restriction under Rule 144. Included in the aggregate number of shares are: 17,496,966 outstanding shares of common stock; 4,761,905 shares issuable upon conversion of outstanding convertible debentures, and 50,000 shares issuable upon exercise of warrants.

All of the shares of our common stock offered under this prospectus are being sold by the holders thereof and not by the company. All costs, expenses and fees in connection with the registration of the selling stockholders’ shares will be borne by us. All brokerage commissions, if any, attributable to the sale of shares by selling stockholders will be borne by such holders.

The relationships among the selling stockholders are: John Hatsopoulos and George Hatsopoulos are brothers.

Each selling stockholder may sell all, none or a portion of the shares offered. We cannot estimate the number of shares of common stock that the selling stockholders will sell pursuant to this prospectus.

Beneficial ownership is determined in accordance with the rules of the SEC. These rules generally attribute beneficial ownership of securities to persons who possess sole or shared voting power or investment power with respect to those securities. Except as otherwise indicated, all persons listed below have sole voting and investment power with respect to the shares beneficially owned by them, subject to applicable community property laws. The information is not necessarily indicative of beneficial ownership for any other purpose. With respect to selling stockholders that are entities, the individuals who have voting or investment power over the shares, as indicated, disclaim beneficial ownership of the securities except for their pecuniary interest therein.

Percentage ownership calculations are based on shares beneficially owned and shares outstanding as of September 30, 2009. The following table sets forth certain beneficial ownership information with regard to the selling stockholders both before the offering and after the offering as if each shareholder had separately sold all shares registered.

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	Shares Beneficially Owned							Shares Beneficially Owned
	Prior to Offering					Shares Being		After Offering
Selling stockholder	Number		Percentage			Offered (1)		Number		Percentage
John N. Hatsopoulos (2)		9,294,495		24.21	%		8,300,000		994,495		2.59	%
George N. Hatsopoulos (3)		6,736,418		17.76	%		6,217,609		518,809		1.37	%
In Holdings Corp. (4)		4,961,905		11.93	%		4,961,905		-			*
Nettlestone Enterprises Limited (5)		3,148,140		8.41	%		676,190		2,471,950		6.60	%
John Hatsopoulos 1989 Family Trust (6)		476,190		1.27	%		476,190		-			*
RBC cees Nominees Ltd. B2599/B3957 (7)		357,143			*		357,143		-			*
RBC cees Nominees Ltd. B2602/B3923 (8)		250,000			*		250,000		-			*
Global Pensions (9)		250,000			*		250,000		-			*
Jeremy Benjamin		119,048			*		119,048		-			*
Despina B. Theocharakis		100,000			*		100,000		-			*
F.V.A Mellish		100,000			*		100,000		-			*
Bruno Meier		100,000			*		100,000		-			*
Gundyco In Trust for Hans Schopper (10)		100,000			*		100,000		-			*
Daniel Barnett (11)		50,000			*		50,000		-			*
Kenneth G. Eisner		50,000			*		50,000		-			*
Edward Miller (12)		140,000			*		40,000		100,000			*
Charles T. Maxwell (13)		442,858		1.18	%		23,810		419,048		1.12	%
David J. Talbot		20,000			*		20,000		-			*
John E. Shore Generation Skipping Trust (14)		20,000			*		20,000		-			*
Gary David Cunningham		14,286			*		14,286		-			*
Adam C. Schachter (15)		12,500			*		12,500		-			*
First Clearing LLC FBO Nancy Schachter (16)		12,500			*		12,500		-			*
Jo Ellen Spitz		12,000			*		12,000		-			*
Tina Argyropoulos		10,000			*		10,000		-			*
Edward J. Barber		10,000			*		10,000		-			*
Michael Zuk (17)		8,000			*		8,000		-			*
Mehdi Sunderji		7,500			*		7,500		-			*
Anthony Jack Smouha		5,000			*		5,000		-			*
Mark Gerstenfeld		4,000			*		4,000		-			*
Santuccio Ricciardi		1,190			*		1,190		-			*
Total		26,813,173					22,308,871

* Represents beneficial ownership of less than 1% of our outstanding common stock.

1. Shares beneficially owned by our security holders and offered hereby consist of: 17,496,966 outstanding shares of common stock; 4,761,905 shares issuable upon conversion of outstanding convertible debentures, and 50,000 shares issuable upon exercise of warrants.

2. Includes: (a) 4,713,570 shares of common stock, par value $0.001 per share held by the John N. Hatsopoulos Qualified Annuity Trust 2008 for which John N. Hatsopoulos is the sole trustee; (b)  3,286,430 shares of common stock, par value $0.001 per share held by John Hatsopoulos and his wife, Patricia Hatsopoulos, as joint tenants with rights of survivorship, each of whom share voting and investment power; (c) 331,400 shares of common stock directly held by Mr. Hatsopoulos; (d) 225,000 shares of common stock that Mr. Hatsopoulos has the right to acquire pursuant to currently exercisable warrants or warrants that become exercisable within 60 days of September 30, 2009; and (e) 738,095 shares of common stock pursuant to currently convertible 8% senior debentures. This amount does not include 476,190 shares purchased on April 23, 2009, held in the John Hatsopoulos 1989 Family Trust for the benefit of Mr. and Mrs. Hatsopoulos’s adult children, for which Paris Nikolaidis is the sole trustee. Mr. Hatsopoulos disclaims beneficial ownership of the shares held by this trust.

3. Includes: (a) 500,000 shares of common stock, par value $0.001 per share held by George Hatsopoulos and his wife, Daphne Hatsopoulos, as joint tenants, each of whom share voting and investment power; (b) 5,737,609 shares of common stock directly held by Mr. Hatsopoulos; (c) 225,000 shares of common stock that Mr. Hatsopoulos has the right to acquire pursuant to currently exercisable warrants or warrants that become exercisable within 60 days of September 30, 2009; and (d) 273,809 shares of common stock pursuant to currently convertible 8% senior debentures. This amount does not include 2,272,391 shares held in the 1994 Hatsopoulos Family Trust for the benefit of Mr. and Mrs. Hatsopoulos’s adult children, for which Daphne Hatsopoulos is the sole trustee. Mr. Hatsopoulos disclaims beneficial ownership of the shares held by this trust.

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4. Includes: (a) 795,238 shares of common stock, par value $0.001 per share directly held by In Holdings Corp.; and (b) 4,166,667 shares of common stock that In Holdings Corp. has the right to acquire pursuant to currently convertible 8% senior debentures. Mr. Konstantinos Samaras exercises sole voting and/or dispositive power with respect to the shares of common stock that In Holdings Corp. holds or has the right to acquire pursuant to currently convertible 8% senior debentures. In Holdings Corp’s address is: Calle 50 No. 2, Edif Universal Planta Baja, Apartado 0816-02580, Republic of Panama.

5. Includes 3,148,140 shares of common stock, par value $0.001 per share held by Nettlestone Enterprises Limited. The address of Nettlestone Enterprises Limited is P.O. Box 665 Roseneath, The Grange, St. Peter Port, Guernsey GY1-3SJ, Channel Islands. Messrs. M.T.R Betley, M.S Heyworth and J.R Plimley are the Directors of the company and may be deemed to exercise voting and/or dispositive power with respect to these shares.

6. Includes 476,190 shares of common stock, par value $0.001 per share purchased on April 23, 2009, held in the John N. Hatsopoulos 1989 Family Trust for the benefit of Mr. and Mrs. Hatsopoulos’s adult children, for which Mr. Paris Nikolaidis is the sole trustee. Mr. Hatsopoulos disclaims beneficial ownership of the shares held by this trust.

7. Includes 357,143 shares of common stock, par value $0.001 per share purchased on July 24, 2009, held by RBC cees Nominees Ltd. B2599/B3957. The address of RBC cees Nominees Ltd. is 19-21 Broad Street, St. Hellier, Jersey JE1 3PB, Channel Islands. Messrs. Jamie Dean and S.E McArthur-Wareing are the the authorised signatories of the company and may be deemed to exercise voting and/or dispositive power with respect to these shares.

8. Includes 250,000 shares of common stock, par value $0.001 per share purchased on July 24, 2009, held by RBC cees Nominees Ltd. B2602/B3923. The address of RBC cees Nominees Ltd. is 19-21 Broad Street, St. Hellier, Jersey JE1 3PB, Channel Islands. Messrs. Jamie Dean and S.E McArthur-Wareing are the the authorised signatories of the company and may be deemed to exercise voting and/or dispositive power with respect to these shares.

9. Includes 250,000 shares of common stock, par value $0.001 per share purchased on July 24, 2009, held by Global Pensions. The address of Global Pensions c/o London Capital Asset Management is 4 Triton Square, Regent’s Place, London NW1 3HG, United Kingdom for the benefit of Mr. Costas Kaplanis. The Directors of Global Pensions are the London and Capital Satellite Board and may be deemed to exercise voting and/or dispositive power with respect to these shares.

10. Includes 100,000 shares of common stock, par value $0.001 per share purchased on July 24, 2009, held by Gundyco In Trust for Hans Schopper AC# 500-01915-27. The address of Gundyco c/o CIBC Wood Gundy is 1, Place Ville Marie, Suite 4125, Montreal QC, H3B 3P9, Canada, for the benefit of Mr. Schopper, for which Mr. Schopper is the sole trustee.

11. Includes a warrant to purchase 50,000 shares of common stock issued on February 24, 2009, to Daniel Barnett, exercisable within 60 days of September 30, 2009.

12. Includes 40,000 shares of restricted common stock, granted to Edward Miller, an employee, by permitting him to purchase an aggregate of 40,000 shares of common stock at a price of $0.001 per share.

13. Includes: (a) 223,810 shares of common stock par value $0.001 per share; (b) options to purchase 100,000 shares of common stock, exercisable within 60 days of September 30, 2009; and (c) 119,048 shares of common stock pursuant to currently convertible 8% senior debentures.

14. Includes 20,000 shares of common stock, par value $0.001 per share purchased on July 24, 2009, held in the John E. Shore Generation Skipping Trust for the benefit of Mr. Shore, for which Mr. Shore is the sole trustee.

15. Mr. Adam Schachter is affiliated with Wells Fargo Advisors. The seller purchased the securities to be resold in the ordinary course of business and at the time of the purchase, the seller had no agreements or understandings directly or indirectly, with any person to distribute the securities.

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16. Includes 12,500 shares of common stock, par value $0.001 per share purchased on July 24, 2009, held in a retirement account by First Clearing LLC FBO Nancy Schachter for the benefit of Mrs. Schachter for which Mrs. Schachter is the sole trustee. Mrs. Schachter is affiliated with Wells Fargo Advisors. The seller purchased the securities to be resold in the ordinary course of business and at the time of the purchase, the seller had no agreements or understandings directly or indirectly, with any person to distribute the securities.

17. Mr. Michael Zuk is affiliated with Oppenheimer & Co. and the seller purchased the securities to be resold in the ordinary course of business. The seller purchased the securities to be resold in the ordinary course of business and at the time of the purchase, the seller had no agreements or understandings directly or indirectly, with any person to distribute the securities.

There are no family relationships among members of our Board or our executive officers, other than Dr. George N. Hatsopoulos and Mr. John N. Hatsopoulos who are brothers. Other than Dr. George N. Hatsopoulos, the company’s Chairman of the Board, John N. Hatsopoulos, the company’s Chief Executive Officer and director, and Charles T. Maxwell, a director of the company, none of the selling stockholders has held any position or office, or had any other material relationship with the company within the past three years.

ACQUISITION TRANSACTIONS

A description of the transactions pursuant to which the shares registered hereby were acquired by the selling shareholders is as follows.

In July 2001 the company issued to John N. Hatsopoulos 3,900,000 shares of common at a price of $0.0007 per share associated with the founding of the company. In November 2000, John N. Hatsopoulos was also issued 3,900,000 shares of common stock at a price of $0.07 per share associated with the founding of Tecogen Inc., which later merged with the company. In April 2006 the company converted $350,000 of short-term notes payable to John N. Hatsopoulos into 500,000 shares of common stock at a price of $0.70 per share. The form of the subscription agreement pursuant to which the shares were sold is filed herewith as Exhibits 10.13.

In July 2001 the company issued to Dr. George N. Hatsopoulos 3,900,000 shares of common at a price of $0.0007 per share associated with the founding of the company. In November 2000, Dr. George N. Hatsopoulos was also issued 1,627,609 shares of common stock at a price of $0.07 per share associated with the founding of Tecogen Inc., which later merged with the company. In April 2002 the company issued to George N. Hatsopoulos 190,000 shares of common at a price of $0.70 per share via a private placement common stock. The form of the subscription agreement pursuant to which the shares were sold is filed herewith as Exhibit 10.12. In April 2006 the company converted $350,000 of short-term notes payable to George N. Hatsopoulos into 500,000 shares of common stock at a price of $0.70 per share. The form of the subscription agreement pursuant to which the shares were sold is filed herewith as Exhibits 10.14.

In December 2003 and November 2004, the company raised in a private placement $140,000 by selling to In Holdings Corp., a selling shareholder, 200,000 shares of common stock at a price of $0.70 per share. The form of the subscription agreement pursuant to which the shares were sold is filed herewith as Exhibit 10.15. In April and June 2006, the company sold an aggregate of $6,075,000 principal amount of its 8% convertible debentures to an aggregate of 15 persons. The fair market value of the common stock on the date of each closing of the convertible debentures was $0.70 and the conversion price into shares of common stock was $0.84. Total proceeds were approximately $5,425,000. One of the selling shareholders that participated in this transaction was In Holdings Corp. by purchasing a principal amount of $4,000,000, representing 4,761,905 shares of common stock issuable upon conversion of outstanding convertible debentures. See Exhibit 10.11 for the form of the subscription agreement pursuant to which the convertible debentures were issued. On April 6, 2009, In Holdings Corp. converted a principal amount of $500,000 into 595,238 shares of the company’s common stock at a conversion price of $0.84.

In February 2007, the company raised in a private placement $1,505,000 by selling to Nettlestone Enterprises Limited, a selling shareholder, 2,150,000 shares of common stock at a price of $0.70 per share. The form of the subscription agreement pursuant to which the shares were sold is filed herewith as Exhibit 10.16.

In December 2008, the company made a restricted stock grant to Edward Miller, an employee, by permitting him to purchase an aggregate of 40,000 shares of common stock at a price of $0.001 per share. The grant vests 25% per year starting on the first anniversary. The restricted stock grant was issued pursuant to the company’s 2005 Stock Incentive Plan. See Exhibit 10.4 for the form of the plan pursuant to which the restricted shares were granted.

8

On February 24, 2009, the company sold to Daniel Barnett, one of the selling shareholders, a warrant to purchase shares of common stock for a purchase price of $10,500. The warrant, which expires on February 24, 2012, gives the investor the right but not the obligation to purchase 50,000 shares of the company’s common stock at an exercise price per share of $3.00. See Exhibit 10.17 for the form of the subscription agreement pursuant to which the warrants were sold.

On April 23, 2009, the company raised $2,260,000 in a private placement of 1,076,190 shares of common stock at a price of $2.10 per share. Included in those shares are 476,190 shares to Nettlestone Enterprises Limited, 476,190 shares to The John Hatsopoulos 1989 Family Trust, 23,810 shares to Charles T. Maxwell and 100,000 shares to Despina B. Theocharakis. All investors that participated in the offering are selling shareholders. See Exhibit 10.18 for the form of the subscription agreement pursuant to which the shares were sold.

On July 24, 2009, the company raised $3,492,650 in a private placement of 1,663,167 shares of common stock at a price of $2.10 per share. The company also granted the investors the right to purchase additional shares of common stock at a purchase price of $3.10 per share by December 18, 2009. Included in those shares are 200,000 shares to Nettlestone Enterprises Limited, 607,143 shares to RBC cees Nominees Ltd., 250,000 shares to Global Pensions, 119,048 shares to Jeremy Benjamin, 100,000 shares to F.V.A Mellish, 100,000 shares to Bruno Meier, 100,000 shares to Gundyco In Trust for Hans Schopper, 50,000 shares to Kenneth G. Eisner, 20,000 shares to David J. Talbot, 20,000 shares to John E. Shore Generation Skipping Trust, 14,286 shares to Gary David Cunningham, 12,500 shares to Adam C. Schachter, 12,500 shares to First Clearing LLC FBO Nancy Schachter, 12,000 shares to Jo Ellen Spitz, 10,000 shares to Tina Argyropoulos, 10,000 shares to Edward J. Barber, 8,000 shares to Michael Zuk, 7,500 shares to Mehdi Sunderji, 5,000 shares to Anthony Jack Smouha, 4,000 shares to Mark Gerstenfeld and 1,190 shares to Santuccio Ricciardi. All investors that participated in the offering are selling shareholders. See Exhibit 10.19 for the form of the subscription agreement pursuant to which the shares were sold.

9

PLAN OF DISTRIBUTION

The selling stockholders and any of their pledgees, assignees and successors-in-interest may, from time to time, sell any or all of their shares of common stock covered by this prospectus at prevailing market prices on the OTC Bulletin Board or at privately negotiated prices. We will pay the expenses incurred to register the shares being offered by the selling stockholders for resale, but the selling stockholders will pay any underwriting discounts and brokerage commissions associated with these sales. Any commission or discount will be negotiated immediately prior to the sale with the broker-dealer or agent. The selling stockholders may use any one or more of the following methods when selling shares:

· ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;

· block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction;

· purchases by a broker-dealer as principal and resale by the broker-dealer for its account;

· privately negotiated transactions; and

· a combination of any such methods of sale.

In addition, any shares that qualify for sale under Rule 144 may be sold under Rule 144 rather than through this prospectus. Shares that qualify for unrestricted sale under Rule 144 may not be sold pursuant to this prospectus.

In offering the shares covered by this prospectus, the selling stockholders and any broker-dealers who execute sales for the selling stockholders may be deemed to be an “underwriter” within the meaning of the Securities Act in connection with such sales. Any profits realized by the selling stockholders and the compensation of any broker-dealer may be deemed to be underwriting discounts and commissions.

Transfer Agent

Our transfer agent is Continental Stock Transfer & Trust Company, 17 Battery Place, New York, NY 10004-1123; tel: 212-509-4000.

EXPERTS

The financial statements of American DG Energy Inc. as of December 31, 2008 and 2007, and for each of the two years in the period ended December 31, 2008, included in our Annual Report on Form 10-K for the year ended December 31, 2008 incorporated by reference in this registration statement have been so incorporated in reliance on the report of Caturano and Company, P.C. (formerly known as Vitale, Caturano & Company, P.C.), independent registered public accountants, given on the authority of said firm as experts in auditing and accounting.

10

PART II

INFORMATION NOT REQUIRED IN THE PROSPECTUS

Item 13.  Other Expenses of Issuance and Distribution.

The following table summarizes the estimated expenses, other than underwriting commissions that we will incur in connection with this offering.

	Amount
Securities and Exchange Commission registration fee	$	3,610
Legal fees and expenses		5,500
Accounting fees and expenses		1,500
Miscellaneous		1,390
Total	$	12,000

Item 14. Indemnification of Directors and Officers.

Section 102 of the Delaware General Corporation Law allows a corporation to eliminate the personal liability of directors of a corporation to the corporation or its stockholders for monetary damages for a breach of fiduciary duty as a director, except where the director breached his duty of loyalty, failed to act in good faith, engaged in intentional misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock repurchase in violation of Delaware corporate law or obtained an improper personal benefit. We have included such a provision in our Restated Certificate of Incorporation.

Section 145 of the Delaware General Corporation Law provides that a corporation has the power to indemnify a director, officer, employee or agent of the corporation and certain other persons serving at the request of the corporation in related capacities against amounts paid and expenses incurred in connection with an action or proceeding to which he is or is threatened to be made a party by reason of such position, if such person shall have acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the corporation, and, in any criminal proceeding, if such person had no reasonable cause to believe his conduct was unlawful; provided that, in the case of actions brought by or in the right of the corporation, no indemnification shall be made with respect to any matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the adjudicating court determines that such indemnification is proper under the circumstances.

Our charter includes a provision that eliminates the personal liability of its directors for monetary damages for breach of fiduciary duty as a director, except for liability:

· for any breach of the director’s duty of loyalty to the company or its stockholders;

· for acts or omissions not in good faith or that involve intentional misconduct or a knowing violation of law;

· under section 174 of the Delaware General Corporation Law regarding unlawful dividends and stock purchases; or

· for any transaction from which the director derived an improper personal benefit.

Our Restated Certificate of Incorporation also provides that:

· we must indemnify our directors and officers to the fullest extent permitted by Delaware law;

· we may, to the extent authorized from time to time by our Board of Directors, indemnify our other employees and agents to the same extent that we indemnified our officers and directors; and

· in the event we do not assume the defense in a legal proceeding, we must advance expenses, as incurred, to our directors and executive officers in connection with a legal proceeding to the fullest extent permitted by Delaware law.

The indemnification provisions contained in our Restated Certificate of Incorporation and Amended and Restated Bylaws are not exclusive of any other rights to which a person may be entitled by law, agreement, vote of stockholders or disinterested directors or otherwise.

In addition, we maintain insurance on behalf of our directors and executive officers insuring them against any liability asserted against them in their capacities as directors or officers or arising out of such status.

11

Item 15. Recent Sales of Unregistered Securities

Set forth below is information regarding common stock issued, warrants issued and stock options granted by the company within the past three years. Also included is the consideration, if any, we received and information relating to the section of the Securities Act, or rule of the SEC, under which exemption from registration was claimed.

Common Stock and Warrants

In April and June 2006, the company sold an aggregate of $6,075,000 principal amount of its 8% convertible debentures to 15 persons. In connection with such transaction, Ernest Aloi, a consultant, received 4,300 shares of common stock as a commission, representing 0.02% of the total shares then outstanding, at a price of $0.001 per share.  All of such investors were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On December 29, 2006, the company raised $1,118,180 in a private placement of 1,597,400 shares of common stock at a price of $0.70 per share. Included in those shares are an aggregate of 700,000 shares sold through the exercise of warrants. In addition, an aggregate of 897,400 shares were sold for cash otherwise than upon exercise of warrants. All of the purchasers were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On December 29, 2006, the company issued 50,000 shares through an option exercise at $0.07 per share.

On March 8, 2007, the company raised $3,004,505 in a private placement of 4,292,150 shares of common stock at a price of $0.70 per share. All of the purchasers were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On April 30, 2007, the company raised $1,120,000 in a private placement of 1,600,000 shares of common stock at a price of $0.70 per share. All of the purchasers were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On June 30, 2007, the company issued 100,000 shares of common stock through an option exercise at $0.07 per share. The purchaser was an accredited investor and such transaction was exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

From February 6, 2008 through December 23, 2008, the company raised $707,000 through the exercise of 1,010,000 warrants. All of the purchasers were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On February 24, 2009, the company sold to Daniel Barnett, a warrant to purchase shares of common stock for a purchase price of $10,500. The warrant, which expires on February 24, 2012, gives the investor the right but not the obligation to purchase 50,000 shares of the company’s common stock at an exercise price per share of $3.00. The purchaser was an accredited investor and such transaction was exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On April 23, 2009, the company raised $2,260,000 in a private placement of 1,076,190 shares of common stock at a price of $2.10 per share. All of the purchasers were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On July 24, 2009, the company raised $3,492,650 in a private placement of 1,663,167 shares of common stock at a price of $2.10 per share. The company also granted the investors the right to purchase additional shares of common stock at a purchase price of $3.10 per share by December 18, 2009. All of the purchasers were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

Restricted Stock Grants

On June 7, 2006, the company made restricted stock grants to 10 employees by permitting them to purchase an aggregate of 257,500 shares of common stock at a price of $0.001 per share. These transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

12

On July 1, 2006, the company made restricted stock grants to 12 persons who were employees of, or otherwise associated with Tecogen Inc., by permitting them to purchase an aggregate of 876,800 shares of common stock at a price of $0.001 per share. These transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On October 4, 2006, the company made a restricted stock grant to one employee for 30,000 shares of common stock at a price of $0.001 per share. This transaction was exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

On February 20, 2007, the company made restricted stock grants to employees, directors and consultants by permitting them to purchase an aggregate of 737,000 shares of common stock, representing at a price of $0.001 per share. These transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

In December 2008, the company made a restricted stock grant to one employee by permitting him to purchase an aggregate of 40,000 shares of common stock at a price of $0.001 per share. Those shares have a vesting schedule of four years. This transaction was exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

8% Convertible Debentures

From April 15, 2006 to June 30, 2006, the company sold an aggregate of $6,075,000 principal amount of its 8% convertible debentures to an aggregate of 15 persons. The initial conversion price into common stock is $0.84. Total proceeds were approximately $5,425,000. In connection with such transaction, Ernest Aloi, a consultant, received 4,300 shares of common stock as a commission and R.F Lafferty & Co., Inc. received a cash commission $33,000. All of such investors were accredited investors, and such transactions were exempt from registration under the Securities Act under Section 4(2) and/or Regulation D thereunder.

13

Item 16. Exhibits and Financial Statement Schedules

(a) Exhibits.

Exhibit
Number	Description
3.1	Certificate of Incorporation (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
3.2	By-laws (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
4.1	Form of Warrant (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
4.2	Warrant to Purchase Shares of Common Stock dated February 24, 2009 (incorporated by reference from the registrant’s current report on Form 8-K, filed with the SEC on February 26, 2009).
5.1	Opinion of William O. Flannery, Esq. (incorporated by reference from the company’s Form SB-2, as amended, originally filed with the SEC on June 27, 2007).
5.2#	Opinion of Sullivan & Worcester LLP dated September 2, 2009.
10.1	Audit Committee Charter (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.2	Compensation Committee Charter (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.3	American Distributed Generation Inc. 2001 Stock Incentive Plan (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.4	2005 Stock Incentive Plan (incorporated by reference from our definitive proxy statement for the 2008 Annual Meeting of shareholders originally filed with the SEC on April 29, 2008).
10.5	Facilities, Support Services and Business Agreement with Tecogen Inc. (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 22, 2006. Confidential treatment has been granted for portions of this document. The confidential portions have been omitted and have been filed separately, on a confidential basis, with the SEC).
10.6	Amendment to Facilities, Support Services and Business Agreement with Tecogen Inc. dated April 1, 2008 (incorporated by reference from the registrant’s Form 10-Q, filed with the SEC on May 14, 2008, for the quarter ended March 31, 2008).
10.7	Amendment No. 2 to Facilities, Support Services and Business Agreement with Tecogen Inc. dated May 15, 2008 (incorporated by reference from the registrant’s Form 10-K, originally filed, filed with the SEC on March 20, 2009).
10.8	Amendment No. 3 to Facilities, Support Services and Business Agreement with Tecogen Inc. dated January 2, 2009 (incorporated by reference from the registrant’s Form 10-K, originally filed, filed with the SEC on March 20, 2009).
10.9	Operating Agreement of American DG New York LLC (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 22, 2006).
10.10	Form of Energy Purchase Agreement (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.11	Form of 8% Senior Convertible Debenture Due 2011 (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.12#	Form of Subscription Agreement for private placement of common stock for American DG Inc.
10.13#	Debt Conversion Agreement with John N. Hatsopoulos dated April 1, 2006.
10.14#	Debt Conversion Agreement with George N. Hatsopoulos dated April 1, 2006.

14

10.15#	Form of Subscription Agreement for private placement of common stock for American Distributed Generation Inc.
10.16#	Form of Subscription Agreement for private placement of common stock for American DG Energy Inc.
10.17	Form of Warrant to purchase shares of common stock, dated February 24, 2009, entered into between the company and Daniel Barnett (incorporated by reference from the registrant’s current Form 8-K, originally filed with the SEC on February 26, 2009).
10.18	Form of Subscription Agreement for common stock (incorporated by reference from the registrant’s current Form 8-K, originally filed with the SEC on April 27, 2009).
10.19	Form of Subscription Agreement for common stock (incorporated by reference from the registrant’s current Form 8-K, originally filed with the SEC on July 27, 2009).
14.1	Code of Business Conduct and Ethics (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
16.1	Letter on change in certifying accountant (incorporated by reference from, the company’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
21.1	List of subsidiaries (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
23.1	Consent of William O. Flannery, Esq. (included in Exhibit 5.1).
23.2#	Consent of Caturano and Company, P.C.
24.1	Power of Attorney (included on signature page).

#   Filed herewith

(b) Financial Statement Schedules.  None

15

Item 17. Undertakings

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the company pursuant to the provisions described under “Indemnification of Directors and Officers” above, or otherwise, the company has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the company of expenses incurred or paid by a director, officer or controlling person of the company in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the company will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

The company hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the company's annual report pursuant to section 13(a) or section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan's annual report pursuant to section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

The company hereby undertakes that:

(1)   To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

a. To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

b. To reflect in the prospectus any facts or events which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in the volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

c. To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

(2)   That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3)   To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4)  Each prospectus filed pursuant to Rule 424(b) as part of this registration statement shall be deemed to be part of and included in the registration statement as of the date it is first used after effectiveness. provided, however, that no statement made in this registration statement or prospectus that is part of this registration statement or made in a document incorporated or deemed incorporated by reference into this registration statement or prospectus that is part of this registration statement will, as to a purchaser with a time of contract of sale prior to such first use, supersede or modify any statement that was made in this registration statement or prospectus that was part of this registration statement or made in any such document immediately prior to such date of first use.

16

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant has authorized this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Waltham, Massachusetts on September 30, 2009.

AMERICAN DG ENERGY INC.

By: /s/ JOHN N. HATSOPOULOS

John N. Hatsopoulos

Chief Executive Officer

POWER OF ATTORNEY AND SIGNATURES

The undersigned officers and directors of the company hereby constitute and appoint John N. Hatsopoulos, Barry J. Sanders and Anthony S. Loumidis, and each of them singly, with full power of substitution, our true and lawful attorneys-in-fact and agents to take any actions to enable the company to comply with the Securities Act, and any rules, regulations and requirements of the SEC, in connection with this registration statement, including the power and authority to sign for us in our names in the capacities indicated below any and all amendments to this registration statement and any other registration statement filed pursuant to the provisions of Rule 462 under the Securities Act.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

Signature	Title	Date
/s/ GEORGE N. HATSOPOULOS	Chairman of the Board	September 30, 2009
George N. Hatsopoulos
/s/ JOHN N. HATSOPOULOS	Chief Executive Officer (Principal Executive Officer)	September 30, 2009
John N. Hatsopoulos
/s/ ANTHONY S. LOUMIDIS	Chief Financial Officer (Principal Financial	September 30, 2009
Anthony S. Loumidis	and Accounting Officer)
/s/ EARL R. LEWIS	Director	September 30, 2009
Earl R. Lewis
/s/ CHARLES T. MAXWELL	Director	September 30, 2009
Charles T. Maxwell
/s/ ALAN D. WEINSTEIN	Director	September 30, 2009
Alan D. Weinstein

17

EXHIBIT INDEX

Exhibit
Number	Description
3.1	Certificate of Incorporation (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
3.2	By-laws (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
4.1	Form of Warrant (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
4.2	Warrant to Purchase Shares of Common Stock dated February 24, 2009 (incorporated by reference from the registrant’s current report on Form 8-K, filed with the SEC on February 26, 2009).
5.1	Opinion of William O. Flannery, Esq. (incorporated by reference from the company’s Form SB-2, as amended, originally filed with the SEC on June 27, 2007).
5.2#	Opinion of Sullivan & Worcester LLP dated September 2, 2009.
10.1	Audit Committee Charter (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.2	Compensation Committee Charter (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.3	American Distributed Generation Inc. 2001 Stock Incentive Plan (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.4	2005 Stock Incentive Plan (incorporated by reference from our definitive proxy statement for the 2008 Annual Meeting of shareholders originally filed with the SEC on April 29, 2008).
10.5	Facilities, Support Services and Business Agreement with Tecogen Inc. (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 22, 2006. Confidential treatment has been granted for portions of this document. The confidential portions have been omitted and have been filed separately, on a confidential basis, with the SEC).
10.6	Amendment to Facilities, Support Services and Business Agreement with Tecogen Inc. dated April 1, 2008 (incorporated by reference from the registrant’s Form 10-Q, filed with the SEC on May 14, 2008, for the quarter ended March 31, 2008).
10.7	Amendment No. 2 to Facilities, Support Services and Business Agreement with Tecogen Inc. dated May 15, 2008 (incorporated by reference from the registrant’s Form 10-K, originally filed, filed with the SEC on March 20, 2009).
10.8	Amendment No. 3 to Facilities, Support Services and Business Agreement with Tecogen Inc. dated January 2, 2009 (incorporated by reference from the registrant’s Form 10-K, originally filed, filed with the SEC on March 20, 2009).
10.9	Operating Agreement of American DG New York LLC (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 22, 2006).
10.10	Form of Energy Purchase Agreement (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.11	Form of 8% Senior Convertible Debenture Due 2011 (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
10.12#	Form of Subscription Agreement for private placement of common stock for American DG Inc.
10.13#	Debt Conversion Agreement with John N. Hatsopoulos dated April 1, 2006.

10.14#	Debt Conversion Agreement with George N. Hatsopoulos dated April 1, 2006.
10.15#	Form of Subscription Agreement for private placement of common stock for American Distributed Generation Inc.
10.16#	Form of Subscription Agreement for private placement of common stock for American DG Energy Inc.
10.17	Form of Warrant to purchase shares of common stock, dated February 24, 2009, entered into between the company and Daniel Barnett (incorporated by reference from the registrant’s current Form 8-K, originally filed with the SEC on February 26, 2009).
10.18	Form of Subscription Agreement for common stock (incorporated by reference from the registrant’s current Form 8-K, originally filed with the SEC on April 27, 2009).
10.19	Form of Subscription Agreement for common stock (incorporated by reference from the registrant’s current Form 8-K, originally filed with the SEC on July 27, 2009).
14.1	Code of Business Conduct and Ethics (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
16.1	Letter on change in certifying accountant (incorporated by reference from, the company’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
21.1	List of subsidiaries (incorporated by reference from the registrant’s Form 10-SB, as amended, originally filed with the SEC on November 2, 2006).
23.1	Consent of William O. Flannery, Esq. (included in Exhibit 5.1).
23.2#	Consent of Caturano and Company, P.C.
24.1	Power of Attorney (included on signature page).

#   Filed herewith

EX-5.2

Exhibit 5.2

Sullivan & Worcester LLP

One Post Office Square

Boston, MA 02109

September 2, 2009

American DG Energy Inc.

45 First Avenue

Waltham, MA 02451

Re:          Registration Statement on Form S-1

 File No. 333-159580

Ladies and Gentlemen:

The following opinion is being furnished to you in connection with the registration under the Securities Act of 1933, as amended (the “Securities Act”), by American DG Energy Inc., a Delaware corporation (the “Company”), of its Common Stock (the “Registered Shares”) consisting of the following: (i) 17,496,966 shares of Common Stock currently outstanding, (ii) 4,761,905 shares of Common Stock issuable upon conversion of outstanding convertible debt and (iii) 50,000 shares of Common Stock issuable upon the exercise of outstanding warrants. The Registered Shares are being registered for resale pursuant to the above-described registration statement (the “Registration Statement”) filed with the Securities and Exchange Commission (the “Commission”) pursuant to the Securities Act of 1933.

We have acted as counsel to the Company in connection with the Registration Statement, and we have examined originals or copies, certified or otherwise identified to our satisfaction, of the Registration Statement and such other documents as we have considered necessary in order to furnish the opinion hereinafter set forth.

We express no opinion herein as to any laws other than the Delaware General Corporation Law, the applicable provisions of the Delaware constitution and reported judicial decisions interpreting these laws, and the federal law of the United States, and we express no opinion as to state securities or blue sky laws.

Based on and subject to the foregoing, we are of the opinion that the outstanding shares of Common Stock being registered are, and the shares of Common Stock issuable upon conversion or exercise of convertible debt or warrants will be upon the valid conversion or exercise thereof will be, duly authorized, validly issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement.  In giving such consent, we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission promulgated thereunder.

Very truly yours,

SULLIVAN AND WORCESTER LLP

EX-10.12

Exhibit 10.12

SUBSCRIPTION AGREEMENT

Gentlemen:

1.              Subscription.  The undersigned, intending to be legally bound, irrevocably subscribes for and agrees to purchase the aggregate number of Shares of the Company’s common stock (“Common Stock”), par value $.01 per share, of American DG Inc., a Delaware corporation (the “Company”), at a purchase price of $1.00 per Share (the “Purchase Price”) indicated on the signature page hereof, on the terms and conditions described herein and in the Confidential Private Placement Memorandum dated June 27, 2002 (which, together with all exhibits, attachments, amendments and supplements thereto, is referred to as the “Memorandum”).  The undersigned herewith delivers to the Company the consideration (“Purchase Price”) required to purchase the Shares subscribed for hereunder by wire transfer funds payable to American DG Inc., 85 First Avenue, Waltham, MA 02451 in the amount of $1.00 for each Share subscribed for hereunder. The minimum investment is for $50,000 (50,000 Shares) unless otherwise determined in the discretion of the Company. The Shares will be issued in accordance with the terms and conditions set forth in the Memorandum. Capitalized terms not otherwise defined in this Agreement have the meanings specified in the Memorandum.

2.              Investor Representations, Warranties and Covenants. The undersigned hereby acknowledges, represents and warrants to, and agrees with the Company as follows:

a.      The undersigned is acquiring the Shares for the undersigned’s own account as principal, for investment purposes only, and not with a view to, or for, resale or distribution of all or any part of the Shares, and no other person has a direct or indirect beneficial interest in such Shares;

b.      The undersigned acknowledges its understanding that the offering and sale of the Shares is intended to be exempt from registration under the Securities Act of 1933, as amended (the “Securities Act”), by virtue of Section 4(2) of the Securities Act and Rule 506 of Regulation D (“Regulation D”) promulgated thereunder and Section 4(6) of the Securities Act, and, in furtherance thereof, the undersigned represents and warrants to and agrees with the Company that the undersigned has the financial ability to bear the economic risk of the undersigned’s investment, has adequate means for providing for the undersigned’s current needs and contingencies and has no need for liquidity with respect to the undersigned’s investment in the Shares.

c.      The undersigned is an “accredited investor” as defined in Rule 501(a) of Regulation D under the Securities Act and has completed the Accredited Investor Questionnaire furnished herewith;

d.      The undersigned:

i.        has been furnished with a copy of the Memorandum and any other documents which have been made available upon request and the undersigned has carefully read the Memorandum and understands and has evaluated the risks of a purchase of Shares, including the risks set forth under “Risk Factors” in the Memorandum; and has relied solely on the information contained in the Memorandum, and any supplemental written information furnished pursuant to Subsection (ii) below;

ii.       has been given the opportunity to ask questions of and receive answers from the Company concerning the terms and conditions of the Offering of the Shares, and has been given the opportunity to obtain additional information necessary to satisfy himself as to the accuracy of the information contained in the Memorandum to the extent that the Company possesses such information or can acquire it without unreasonable effort or expense and has not been furnished with any other offering literature except as referred to in the Memorandum;

iii.      has not relied on any oral representation, warranty or information in connection with the Offering of the Shares by the Company, or any officer, employee, agent or affiliate of the Company or the Placement Agent;

iv.      has determined the Shares are a suitable investment for the undersigned and that at this time the undersigned can bear a complete loss of the undersigned’s investment therein;

v.       has such knowledge and experience in financial and business matters that the undersigned is capable of evaluating the merits and risks of the undersigned’s investment in the Shares;

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vi.      If the undersigned is a corporation, limited liability company, partnership, trust, qualified plan or other entity, it is authorized and qualified to become a holder of Shares, and the person signing this Subscription Agreement on behalf of such entity has been duly authorized to do so;

vii.     Any information which the undersigned has heretofore furnished and herewith furnishes to the Company with respect to the undersigned’s financial position and business experience, including, without limitation, the undersigned’s Accredited Investor Questionnaire, is correct and complete as of the date of this Agreement and if there should be any material change in such information prior to issuance to the undersigned of Shares, the Undersigned will immediately furnish such revised or corrected information to the Company;

viii.    The foregoing acknowledgments, representations, warranties and agreements shall survive the closing at which the Shares are issued;

ix.       The undersigned acknowledges that the undersigned has not purchased the Shares as a result of any general solicitation or general advertising; and

x.       The undersigned’s overall commitment to investments which are not readily marketable is not disproportionate to the undersigned’s net worth, and the undersigned’s prospective investment in the Company and will not cause such overall commitment to become excessive.

3.              Investor Awareness.  The undersigned acknowledges that:

a.      No federal or state agency has passed upon the Shares or made any finding or determination as to the fairness of this investment;

b.      There is no established market for the Shares and no assurance has been given that any public market for them will develop;

c.      The Shares may not be sold, pledged or otherwise transferred, except as may be permitted under the Securities Act and applicable state securities laws pursuant to registration or exemption therefrom; and accordingly, the undersigned may be required to bear the financial risks of an investment in the Shares for an indefinite period of time;

d.      The undersigned consents to (i) the placing of a legend substantially in the form set forth below on the certificates representing the Shares stating that the securities have not been registered and setting forth the restriction on transfer contemplated hereby, and (ii) the placing of a stop transfer order on the books of the Company and with any transfer agents against the securities included within the Shares.

A legend shall be placed on certificates representing the Shares substantially in the form set forth below:

“THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS, AND MAY NOT BE TRANSFERRED, SOLD OR OTHERWISE DISPOSED OF WITHOUT AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT OR PURSUANT TO AN EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE STATE SECURITIES LAWS, SUPPORTED BY AN OPINION OF COUNSEL, REASONABLY SATISFACTORY TO THE COMPANY AND ITS COUNSEL, THAT SUCH REGISTRATION IS NOT REQUIRED.”

4.              Miscellaneous.

a.      Indemnity. The undersigned agrees to indemnify and hold harmless the Company and its affiliates, the Placement Agent and its affiliates, and each of their respective directors, officers, employees, agents and controlling persons (the Company, the Placement Agent, and each such person being an “Indemnified Party”), from and against any and all losses, claims, damages, liabilities and expenses whatsoever (including, but not limited to, any and all expenses whatsoever reasonably incurred investigating, preparing or defending against any litigation commenced or threatened or any claim whatsoever), joint or several, as incurred, to which such Indemnified Party may become subject under any applicable United States federal or state law or the laws of any other domestic or foreign jurisdiction, or otherwise, and related to or arising out of or based upon any false representation, warranty or acknowledgment, or breach or failure by the undersigned to comply with any covenant or agreement made by the undersigned herein or in any other document furnished by the undersigned to any of the foregoing in connection with this transaction.

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b.      Modification.  Except as otherwise provided herein, neither this Agreement nor any provisions hereof shall be modified, discharged or terminated except by an instrument in writing signed by the party against whom any waiver, change, discharge or termination is sought.

c.      Binding Effect.  Except as otherwise provided herein, this Agreement shall be binding upon and inure to the benefit of the parties and their heirs, executors, administrators, successors, legal representatives and assigns.  If the undersigned is more than one person, the obligation of the undersigned shall be joint and several and the agreements, covenants,  representations, warranties and acknowledgments herein contained shall be deemed to be made by and be binding upon each such person and his heirs, executors, administrators and successors.

d.      Entire Agreement.  This instrument contains the entire agreement of the parties and there are no representations, warranties, acknowledgments, covenants or other agreements except as stated or referred to herein.

e.      Assignability.  This Agreement is not transferable or assignable by the undersigned.

f.      Law Governing.  This Agreement shall be enforced, governed and construed in all respects in accordance with the laws of the State of Massachusetts, without giving effect to conflicts of laws principles.

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ALL SUBSCRIBERS MUST COMPLETE THIS PAGE

IN WITNESS WHEREOF, the undersigned has executed this Agreement on the day of  ___________________, 2002.

$  _________________

   Total Purchase Price

Please note that the number of Shares you receive will be based upon the total purchase price.

Manner in which Title is to be held (Please Check One):

1. __________ Individual

2. __________ Joint Tenants with Right of Survivorship

3. __________ Community Property

4. __________ Tenants in Common

5. __________ Corporation / Limited Liability Company / Partnership

6. __________ IRA

7. __________ Trust / Estate / Pension or Profit Sharing Plan Date Opened: __________

8. __________ As a Custodian for __________________ Under the Uniform Gift to Minors Act of the State of __________________

9. __________ Married with Separate Property

       10. __________ Keogh

       11. __________ Tenants by the Entirety

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EXECUTION BY NATURAL PERSONS

Exact Name in Which Title is to be Held

Name of Purchaser (Print)	Name of Additional Purchaser
Address	Address
City, State and Zip Code	City, State and Zip Code
Social Security Number	Social Security Number
Signature of Purchaser	Signature of Additional Purchaser

ACCEPTED this         day of ___________, 2002 on behalf of the Company.

By:

Name:

Title:

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EXECUTION BY SUBSCRIBER THAT IS AN ENTITY

(Corporation, Limited Liability Company, Partnership, Trust, Etc.)

Name of Entity (Please Print)

Date of Incorporation or Organization:  ___________________________________________

State of Principal Offices: ______________________________________________________

Federal Taxpayer Identification Number: __________________________________________

By:

Title:

Attest: _________________________
(If Entity is a Corporation)
	Address
	Taxpayer Identification Number

ACCEPTED this ________ day of ___________, 2002 on behalf of the Company.

By:

Name:

Title:

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EX-10.13

 Exhibit 10.13

DEBT CONVERSION AGREEMENT

Debt Conversion Agreement (this “Agreement”) dated as of April 1, 2006 between John N. Hatsopoulos (the “Lender”) and American DG Energy Inc. (the “Borrower”).

The Lender is the holder of Demand Promissory Notes dated as of March 26, 2003, January 20, 2004, March 24, 2004, April 21, 2004 and June 3, 2004 issued by the Borrower (formerly American DG Inc.) in the aggregate principal amount of Nine Hundred Thousand Dollars ($900,000.00) (collectively the “Notes”).

The Lender is willing to convert the principal amount of the Notes and a portion of the accrued and unpaid interest on the Notes into (a) shares of the Common Stock, par value $.001 per share of the Borrower (the “Common Stock”), and (b) the Borrower’s 8% Senior Convertible Debentures Due 2011 (the “Debentures”), and the Lender is willing to accept such conversion.

NOW, THEREFORE, the undersigned, for good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, hereby agree as follows:

1.           (a)  As of the date hereof, the Lender hereby agrees to convert Notes in the principal amount of Three Hundred Fifty Thousand Dollars ($350,000.00) into shares of Common Stock at a conversion rate of Seventy Cents ($.70) per share of Common Stock or 500,000 shares of Common Stock (the “Shares”), (b) as of April 15, 2006, the Lender agrees to convert Notes in the principal amount of Five Hundred Fifty Thousand Dollars ($550,000.00) into Five Hundred Fifty Thousand Dollars ($550,000.00) principal amount of the Debentures, (c) as of the date hereof, the Lender agrees to accept Debentures in the principal amount of Seventy Thousand Dollars ($70,000.00) in lieu of an equal amount of accrued and unpaid interest due and payable on the Notes, and (d) as of the date hereof, the Lender hereby agrees to accept from the Borrower in cash the sum of Four Thousand Seven Hundred and Forty Two Dollars and Eighty Eight Cents ($4,742.88) for the balance of the accrued and unpaid interest due and payable on the Notes. Upon receipt and cancellation of the Notes, the Borrower hereby agrees to issue such Shares and Debentures and to pay such cash to the Lender. The parties agree to execute and deliver such further documents as may be necessary to give effect to the conversion and cancellation of the Notes.

2.           The Borrower hereby represents and warrants to the Lender that (a) the Borrower is a corporation duly organized, validly existing and in good standing under the laws of the State of Delaware (b) the Borrower has all required corporate power and authority to carry on its business as presently conducted, to enter into and perform its obligations under this Agreement, (c) this Agreement constitutes the legal, valid and binding obligation of the Borrower, enforceable against it in accordance with its terms, except (i) as limited by applicable bankruptcy, insolvency, reorganization, moratorium, and other laws of general application affecting enforcement of creditors’ rights generally or by equitable principles, and (ii) as limited by laws relating to the availability of specific performance, injunctive relief, or other equitable remedies, (d) the execution, delivery and performance of this Agreement has been duly authorized by all necessary corporate action of the Borrower.  Except as set forth in the preceding sentence, the Borrower makes no representation or warranty to the Lender with respect to either the Shares or the Borrower.

4.           The Lender hereby represents and warrants to the Borrower that (a) the Lender holds full right, title and interest to the Notes free of any liens or other encumbrances, (b) the Lender has the legal capacity to enter into and to perform his obligations under this Agreement and to carry out the transactions contemplated hereby, (c) this Agreement constitutes the legal, valid and binding obligation of the Lender, enforceable against the Lender in accordance with its terms, except (i) as limited by applicable bankruptcy, insolvency, reorganization, moratorium, and other laws of general application affecting enforcement of creditors’ rights generally or by equitable principles, and (ii) as limited by laws relating to the availability of specific performance, injunctive relief, or other equitable remedies, and (d) the Lender is acquiring the Shares for the Lender’s own account and not with a view to their distribution within the meaning of Section 2(11) of the U.S. Securities Act of 1933, as amended.

  This Agreement shall be governed by and construed in accordance with the laws of the Commonwealth of Massachusetts. Executed as of the date set forth above.

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THE BORROWER		THE LENDER
American DG Energy Inc.		John N. Hatsopoulos
By:
	Anthony S. Loumidis	John N. Hatsopoulos
	Chief Financial Officer

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EX-10.14

Exhibit 10.14

DEBT CONVERSION AGREEMENT

Debt Conversion Agreement (this “Agreement”) dated as of April 1, 2006 between George and Daphne Hatsopoulos (the “Lenders”) and American DG Energy Inc. (the “Borrower”).

The Lenders are the holders of Demand Promissory Notes dated as of August 14, 2002, March 26, 2003 and June 15, 2004 issued by the Borrower (formerly American DG Inc.) in the aggregate principal amount of Three Hundred and Fifty Thousand Dollars ($350,000.00)(collectively the “Notes”).

The Lenders are willing to convert the principal amount of the Notes and a portion of the accrued and unpaid interest on the Notes into (a) shares of the Common Stock, par value $.001 per share of the Borrower (the “Common Stock”), and (b) the Borrower’s 8% Senior Convertible Debentures Due 2011 (the “Debentures”), and the Lender is willing to accept such conversion.

NOW, THEREFORE, the undersigned, for good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, hereby agree as follows:

3.            (a)  As of the date hereof, the Lenders hereby agree to convert Notes in the principal amount of Three Hundred Fifty Thousand Dollars ($350,000.00) into shares of Common Stock at a conversion rate of Seventy Cents ($.70) per share of Common Stock or 500,000 shares of Common Stock (the “Shares”), (b) as of April 15, 2006, the Lenders hereby agree to accept Debentures in the principal amount of Thirty Thousand Dollars ($30,000.00) in lieu of an equal amount of accrued and unpaid interest due and payable on the Notes, and (c) as of the date hereof, the Lender hereby agrees to accept from the Borrower in cash the sum of Two Thousand and Eighty Nine Dollars and Forty One Cents ($2,089.41) for the balance of the accrued and unpaid interest due and payable on the Notes. Upon receipt and cancellation of the Notes, the Borrower hereby agrees to issue such Shares and Debentures and to pay such cash to the Lender. The parties agree to execute and deliver such further documents as may be necessary to give effect to the conversion and cancellation of the Notes.

4.           The Borrower hereby represents and warrants to the Lenders that (a) the Borrower is a corporation duly organized, validly existing and in good standing under the laws of the State of Delaware (b) the Borrower has all required corporate power and authority to carry on its business as presently conducted, to enter into and perform its obligations under this Agreement, (c) this Agreement constitutes the legal, valid and binding obligation of the Borrower, enforceable against it in accordance with its terms, except (i) as limited by applicable bankruptcy, insolvency, reorganization, moratorium, and other laws of general application affecting enforcement of creditors’ rights generally or by equitable principles, and (ii) as limited by laws relating to the availability of specific performance, injunctive relief, or other equitable remedies, (d) the execution, delivery and performance of this Agreement has been duly authorized by all necessary corporate action of the Borrower.  Except as set forth in the preceding sentence, the Borrower makes no representation or warranty to the Lenders with respect to either the Shares or the Borrower.

4.           The Lenders hereby represent and warrant to the Borrower that (a) the Lenders hold full right, title and interest to the Notes free of any liens or other encumbrances, (b) the Lenders have the legal capacity to enter into and to perform their obligations under this Agreement and to carry out the transactions contemplated hereby, (c) this Agreement constitutes the legal, valid and binding obligation of the Lenders, enforceable against the Lenders in accordance with its terms, except (i) as limited by applicable bankruptcy, insolvency, reorganization, moratorium, and other laws of general application affecting enforcement of creditors’ rights generally or by equitable principles, and (ii) as limited by laws relating to the availability of specific performance, injunctive relief, or other equitable remedies, and (d) the Lenders are acquiring the Shares for the Lenders’ own account and not with a view to their distribution within the meaning of Section 2(11) of the U.S. Securities Act of 1933, as amended.

  This Agreement shall be governed by and construed in accordance with the laws of the Commonwealth of Massachusetts. Executed as of the date set forth above.

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THE BORROWER		THE LENDERS
American DG Energy Inc.		Daphne P. Hatsopoulos
By:
	Anthony S. Loumidis	Daphne P. Hatsopoulos
	Chief Financial Officer
		George N. Hatsopoulos
		George N. Hatsopoulos

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EX-10.15

Exhibit 10.15

AMERICAN DISTRIBUTED GENERATION INC.

SUBSCRIPTION AGREEMENT

Dear Sir or Madam:

1.           Subscription. The undersigned, intending to be legally bound, irrevocably subscribes for and agrees to purchase the aggregate number of shares of the common stock (“Common Stock”), par value $.001 per share (each a “Share” and collectively, the “Shares”) of American Distributed Generation Inc., a Delaware corporation  (the “Company”), indicated on the signature page hereof, on the terms and conditions described herein and in the Confidential Private Placement Memorandum dated August 2004 (which, together with all exhibits, attachments, amendments and supplements thereto, is referred to as the “Memorandum”). The undersigned has also completed the Accredited Investor Questionnaire attached to this Agreement.

The undersigned herewith delivers to the Company the consideration (“Purchase Price”) required to purchase the Shares subscribed for hereunder by wire transfer funds payable to: American Distributed Generation Inc., 45 First Avenue, Waltham, MA 02451. The minimum investment is for $50,000 unless otherwise determined in the discretion of the Company. The Shares will be issued in accordance with the terms and conditions set forth in the Memorandum. Capitalized terms not otherwise defined in this Agreement have the meanings specified in the Memorandum.

2.           Investor Representations, Warranties and Covenants. The undersigned hereby acknowledges, represents and warrants to, and agrees with the Company as follows:

(a)          The undersigned is acquiring the Shares for the undersigned’s own account as principal, for investment purposes only, and not with a view to, or for, resale or distribution of all or any part of the Shares and no other person has a direct or indirect beneficial interest in such Shares;

(b)          The undersigned acknowledges its understanding that the offering and sale of the Shares is intended to be exempt from registration under the Securities Act of 1933, as amended (the “Securities Act”), by virtue of Section 4(2) of the Securities Act and Rule 505 of Regulation D (“Regulation D”) promulgated thereunder and Section 4(6) of the Securities Act, and, in furtherance thereof, the undersigned represents and warrants to and agrees with the Company that the undersigned has the financial ability to bear the economic risk of the undersigned’s investment, has adequate means for providing for the undersigned’s current needs and contingencies and has no need for liquidity with respect to the undersigned’s investment in the Shares.

(c)          The undersigned is an “accredited investor” as defined in Rule 501(a) of Regulation D under the Securities Act. The undersigned hereby certifies that the information set forth in the attached Accredited Investor Questionnaire is accurate and complete as of the date of this Agreement.

(d)          The undersigned:

(i)           has been furnished with a copy of the Memorandum and any other documents which have been made available upon request and the undersigned has carefully read the Memorandum and understands and has evaluated the risks of a purchase of the Shares including the risks set forth under “Risk Factors” in the Memorandum; and has relied solely on the information contained in the Memorandum, and any supplemental written information furnished pursuant to Subsection (ii) below;

(ii)          has been given the opportunity to ask questions of and receive answers from the Company concerning the terms and conditions of the Offering of the Shares and has been given the opportunity to obtain additional information necessary to satisfy the undersigned as to the accuracy of the information contained in the Memorandum to the extent that the Company possesses such information or can acquire it without unreasonable effort or expense and has not been furnished with any other offering literature except as referred to in the Memorandum;

(iii)         has not relied on any oral representation, warranty or information in connection with the Offering of the Shares by the Company, or any officer, employee, agent or affiliate of the Company;

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(iv)        has determined that the Shares are a suitable investment for the undersigned and that at this time the undersigned can bear a complete loss of the undersigned’s investment therein;

(v)         has such knowledge and experience in financial and business matters that the undersigned is capable of evaluating the merits and risks of the undersigned’s investment in the Shares;

(e)          If the undersigned is a corporation, limited liability company, partnership, trust, qualified plan or other entity, it is authorized and qualified to become a holder of the Shares and the person signing this Subscription Agreement on behalf of such entity has been duly authorized to do so;

(f)           Any information which the undersigned has heretofore furnished and herewith furnishes to the Company with respect to the undersigned’s financial position and business experience is correct and complete as of the date of this Agreement and if there should be any material change in such information prior to issuance to the undersigned of the Shares, the undersigned will immediately furnish such revised or corrected information to the Company;

(g)          The foregoing acknowledgments, representations, warranties and agreements shall survive the closing at which the Shares are issued;

(h)          The undersigned acknowledges that the undersigned has not purchased the Shares  as a result of any general solicitation or general advertising; and

(i)           The undersigned’s overall commitment to investments which are not readily marketable is not disproportionate to the undersigned’s net worth, and the undersigned’s prospective investment in the Company and will not cause such overall commitment to become excessive.

3.           Investor Awareness.  The undersigned acknowledges that:

(a)          No federal or state agency has passed upon the Shares or made any finding or determination as to the fairness of this investment;

(b)          There is no established market for the Shares and no assurance has been given that any public market for them will develop;

(c)          The Shares may not be sold, pledged or otherwise transferred, except as may be permitted under the Securities Act and applicable state securities laws pursuant to registration or exemption therefrom; and accordingly, the undersigned may be required to bear the financial risks of an investment in the Shares for an indefinite period of time;

(d)          The undersigned consents to (i) the placing of a legend substantially in the form set forth below on the certificates representing the Shares stating that the securities have not been registered and setting forth the restriction on transfer contemplated hereby, and (ii) the placing of a stop transfer order on the books of the Company and with any transfer agents against the Shares.

“The shares represented by this certificate have not been registered under the Securities Act of 1933, as amended. These shares have been acquired for investment and not with a view to distribution or resale and may not be sold, mortgaged, pledged, hypothecated or otherwise transferred without an effective registration statement for such sales under the Securities Act of 1933, or an opinion of counsel for the corporation that registration is not required under such Act”.

4.           Miscellaneous.

(a)          Indemnity. The undersigned agrees to indemnify and hold harmless the Company, its affiliates, directors, officers, employees, agents and controlling persons (the Company and each such person being an “Indemnified Party”), from and against any and all losses, claims, damages, liabilities and expenses whatsoever (including, but not limited to, any and all expenses whatsoever reasonably incurred investigating, preparing or defending against any litigation commenced or threatened or any claim whatsoever), joint or several, as incurred, to which such Indemnified Party may become subject under any applicable United States federal or state law or the laws of any other domestic or foreign jurisdiction, or otherwise, and related to or arising out of or based upon any false representation, warranty or acknowledgment, or breach or failure by the undersigned to comply with any covenant or agreement made by the undersigned herein or in any other document furnished by the undersigned to any of the foregoing in connection with this transaction.

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(b)          Modification.  Except as otherwise provided herein, neither this Agreement nor any provisions hereof shall be modified, discharged or terminated except by an instrument in writing signed by the party against whom any waiver, change, discharge or termination is sought.

(c)          Binding Effect.  Except as otherwise provided herein, this Agreement shall be binding upon and inure to the benefit of the parties and their heirs, executors, administrators, successors, legal representatives and assigns. If the undersigned is more than one person, the obligation of the undersigned shall be joint and several and the agreements, covenants, representations, warranties and acknowledgments herein contained shall be deemed to be made by and be binding upon each such person and his heirs, executors, administrators and successors.

(d)          Entire Agreement.  This instrument contains the entire agreement of the parties and there are no representations, warranties, acknowledgments, covenants or other agreements except as stated or referred to herein.

(e)          Assignability.  This Agreement is not transferable or assignable by the undersigned.

(f)          Governing Law and Forum.  Notwithstanding the place where this Agreement may be executed by any of the parties hereto, all the terms and provisions hereof shall be construed in accordance with and governed by the laws of the Commonwealth of Massachusetts, without giving effect to its conflict of law principles. Any dispute which may arise out of or in connection with this Agreement shall be adjudicated before a court located in Middlesex County, Massachusetts and the parties hereby submit to the exclusive jurisdiction of the courts of the Commonwealth of Massachusetts located in Boston, Massachusetts and of the federal courts in Boston, Massachusetts with respect to any action or legal proceeding commenced by any party, and irrevocably waive any objection they now or hereafter may have respecting the venue of any such action or proceeding brought in such a court or respecting the fact that such court is an inconvenient forum, relating to or arising out of this Agreement or any acts or omissions relating to the sale of the Shares and the undersigned consents to the service of process in any such action or legal proceeding by means of registered or certified mail, return receipt requested, in care of the address set forth below or such other address as the undersigned shall furnish in writing to the Company. In the event any such action is brought, whether at law or in equity, then the prevailing party shall be paid its reasonable attorney's fees, expenses and disbursements arising out of such action. The undersigned hereby waives trial by jury in any action or proceeding involving, directly or indirectly, any matter (whether sounding in tort, contract, fraud or otherwise) in any way arising out of or in connection with this Agreement or the Holder’s purchase of the Shares.

[The balance of this page has been intentionally left blank.]

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ALL SUBSCRIBERS MUST COMPLETE THIS PAGE

IN WITNESS WHEREOF, the undersigned has executed this Subscription Agreement on the day of ___________________, 2004.

Number of Shares Subscribed for: ____________

Purchase Price:    $______________

Manner in which Title is to be held (Please Check One):

1. _________ Individual

2. _________ Joint Tenants with Right of Survivorship

3. _________ Community Property

4. _________ Tenants in Common

5. _________ Corporation / Limited Liability Company / Partnership

6. _________ IRA

7. _________ Trust / Estate / Pension or Profit Sharing Plan Date Opened: __________

8. _________ As a Custodian for __________________ Under the Uniform Gift to Minors Act of the State of __________________

9. _________ Married with Separate Property

10. _________ Keogh

11. _________ Tenants by the Entirety

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EXECUTION BY NATURAL PERSONS

___________________________________

Exact Name in Which Title is to be Held

Name of Purchaser (Print)	Name of Additional Purchaser
Address	Address
City, State and Zip Code	City, State and Zip Code
Social Security Number	Social Security Number
Signature of Purchaser	Signature of Additional Purchaser

ACCEPTED this _______ day of _______________, 2004 on behalf of the Company.

By:

Name:

Title:

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EXECUTION BY SUBSCRIBER THAT IS AN ENTITY

(Corporation, Limited Liability Company, Partnership, Trust, Etc.)

________________________________________________________

Name of Entity (Please Print)

Date of Incorporation or Organization:  ___________________________________________

State of Principal Offices: _____________________________________________________

Federal Taxpayer Identification Number: __________________________________________

	By:
	Title:
Attest: _________________________	Address:
(If Entity is a Corporation)
	Taxpayer Identification Number

ACCEPTED this         day of _______________, 2004 on behalf of the Company.

By:

Name:

Title:

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ACCREDITED INVESTOR QUESTIONNAIRE

Please check the box below that best characterizes the person or entity subscribing for the Shares under the terms of the foregoing Subscription Agreement.

¨ a natural person whose individual net worth, or joint net worth with that person’s spouse, at the time of his purchase exceeds US $1,000,000.

¨ a natural person who had an individual income in excess of $200,000 in each of the two most recent years or joint income with that person’s spouse in excess of $300,000 in each of those years and has a reasonable expectation of reaching the same income level in the current year.

¨ an organization described in Section 501(c)(3) of the Internal Revenue Code, a corporation, a Massachusetts or similar business trust or a partnership, in each case, not formed for the purpose of this investment, with total assets in excess of US $5,000,000.

¨ a director, executive officer, or general partner of the issuer of the securities being offered or sold, or any director, executive officer, or general partner of a general partner of that issuer.

¨ a trust with total assets in excess of US $5,000,000, not formed for the specific purpose of acquiring the securities offered, whose purchase is directed by a sophisticated person as described in Rule 506(b)(2)(ii) of the Securities Act of 1933.

¨ an entity in which all of the equity owners are accredited investors.

¨ a private business development company as defined in Section 202(a)(22) of the Investment Advisers Act of 1940.

¨ a Small Business Investment Company licensed by the U.S. Small Business Administration  under Section 301(c) or (d) of the Small Business Investment Act of 1958.

¨ an investment company registered under the Investment Company Act of 1940 or a business development company as defined in Section 2(a)(48) of that Act.

¨ a bank as defined in Section 3(a)(2) or a savings and loan association or other institution defined in Section 3(a)(5)(A) of the Securities Act of 1933 acting in either an individual or fiduciary capacity.

¨ an insurance company as defined in Section 2(13) of the Securities Act of 1933.

¨ an employee benefit plan within the meaning of Title I of the Employee Retirement Income Security Act of 1974 whose investment decision is made by a fiduciary which is either a bank, savings and loan association, insurance company, or registered investment advisor, or whose total assets exceed US $5,000,000, or, if a self-directed plan, a plan whose investment decisions are made solely by persons who are accredited investors.

¨ any broker or dealer registered pursuant to Section 15 of the Securities Exchange Act of 1934.

¨ any plan established and maintained by a state, its political subdivisions, or any agency or instrumentality of a state or its political subdivisions for the benefit of its employees, if such plan has total assets in excess of $5,000,000.

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EX-10.16

Exhibit 10.16

AMERICAN DG ENERGY INC.

COMMON STOCK PURCHASE AGREEMENT

TO:  American DG Energy Inc.

45 First Avenue

Waltham, Massachusetts 02451

Ladies and Gentlemen:

The undersigned (the “Investor”) desires to purchase from American DG Energy Inc., a Delaware corporation (the “Company”), _______ shares of its Common Stock, par value $.001 per share (the “Common Stock”). The purchase price for each share of Common Stock is $0.70.

1.          Subscription

a.           Subject to the terms and conditions of this Agreement (this “Agreement”), the Investor agrees to subscribe for and purchase from the Company and tenders this subscription for _______ shares of Common Stock (the “Shares”) together with payment of the subscription price for the Shares in the amount of $________. The subscription price is referred to in this Agreement as the “Funds”.

b.           Tender of the Funds shall be made by delivery of a personal or bank check payable to the Company or by wire transfer to the Company’s designated bank account, together with executed copies of this Agreement. The Investor should deliver the executed subscription documents and payment for the Shares to the Company, at 45 First Avenue, Waltham, MA  02451 Attention: Anthony S. Loumidis, Chief Financial Officer, Phone (781) 622-1117.

2.          Acceptance of Agreement

It is understood and agreed that this Subscription is made subject to the following terms and conditions:

The Company shall have the right to accept or reject this Subscription, in whole or in part, for any reason, the ineligibility of a subscriber under applicable state or foreign securities laws, for any other reason or for no reason. If this Subscription is rejected, the Funds previously delivered to the Company will be returned to the Investor.

b.           Two complete copies of this Agreement will be executed by the Investor. If this Subscription is accepted, one copy of this Common Stock Purchase Agreement as accepted by the Company shall be delivered to the Investor.

c.           If this Subscription is accepted in part and rejected in part, the Investor will be so notified, at which time the excess Funds previously delivered to the Company will be returned to the Investor.

3.          Representations and Warranties of the Investor

In order to induce the Company to accept this Agreement, the Investor hereby represents and warrants to the Company as follows:

a.           THE INVESTOR HAS READ CAREFULLY AND UNDERSTANDS THIS AGREEMENT AND HAS CONSULTED THE INVESTOR'S OWN ATTORNEY, ACCOUNTANT OR INVESTMENT ADVISER WITH RESPECT TO THE INVESTMENT CONTEMPLATED HEREBY AND ITS SUITABILITY FOR THE INVESTOR.  THE INVESTOR HAS HAD AN OPPORTUNITY TO ASK QUESTIONS OF AND RECEIVED ANSWERS FROM THE COMPANY, OR A PERSON OR PERSONS ACTING ON THE COMPANY'S BEHALF, CONCERNING THE TERMS AND CONDITIONS OF THIS INVESTMENT AND THE BUSINESS OF THE COMPANY, AND HAS RECEIVED AND REVIEWED ALL ADDITIONAL DOCUMENTATION REGARDING THE BUSINESS AND OPERATIONS OF THE COMPANY THAT HE OR SHE HAS REASONABLY REQUESTED.

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b.           The Investor (i) has no need for liquidity in the investment in the Shares, (ii) is able to bear the substantial economic risks of an investment in the Shares for an indefinite period, and (iii) at the present time, could afford the complete loss of such investment in the Shares.

c.           The address set forth at the end of this Agreement is the Investor's true and correct residence, and the Investor has no present intention of changing such residence to any other state or jurisdiction.

d.           The Investor confirms that all documents, records and books pertaining to the investment in the Company reasonably requested by the Investor have been made available to the Investor. The undersigned has relied only on such documents and that no written or oral representation or information inconsistent with such information has been made or furnished to the Investor in connection with the Shares and if so made, has not been relied upon.

e.           The Investor understands that the Shares have not been registered under the Securities Act, nor pursuant to the provisions of the securities laws or other laws of any other applicable jurisdictions, in reliance on exemptions for private offerings contained in the Securities Act and in the laws of such jurisdictions. The Investor represents to the Company that he is an “accredited investor”, as such term is defined in Rule 501(a) of Regulation D under the Securities Act of 1933, as amended. The Investor is fully aware that the Shares to which he or she is subscribing are to be sold in reliance upon such exemptions based upon his or her representations, warranties and agreements set forth in this Agreement. The Investor is fully aware that he or she must bear the economic risk of his or her investment in the Company for an indefinite period of time because the Shares have not been registered under the Securities Act, and, therefore, cannot be offered or sold unless they are subsequently registered under the Securities Act or an exemption from such registration is available. The Investor further understands that the Company has no intention and is under no obligation to register its Shares under the Securities Act or to comply with the requirements for any exemption that might otherwise be available, or to supply the Investor with any information necessary to enable the Investor to make routine sales of the Shares under Rule 144under the Securities Act (which it understands is not now, and will not likely be, available) or any rule of the Securities and Exchange Commission or any successor thereto.

f.           The Investor understands that the certificate(s) representing the Shares will bear the following legend restricting its transfer and that a notation restricting such transfer will be made on the stock transfer books of the Company:

“THE SHARES OF STOCK REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT") OR THE APPLICABLE SECURITIES LAWS OF ANY STATE OR OTHER JURISDICTION. THESE SHARES HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO THEIR DISTRIBUTION OR RESALE.  SUCH SHARES MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT FOR SUCH SHARES UNDER THE ACT, OR AN OPINION OF COUNSEL SATISFACTORY IN FORM AND SUBSTANCE TO THE COMPANY TO THE EFFECT THAT SUCH REGISTRATION IS NOT REQUIRED.”

g.           The Shares are being acquired solely for the Investor's own account, for investment and are not being purchased with a view to or for the resale or other distribution of the Shares; and the Investor has no present plans to enter into any contract, undertaking, agreement or arrangement relating to any resale or other distribution of the Shares.

h.           The Investor understands that this Subscription may be accepted or rejected in whole or in part in the sole and absolute discretion of the Company, and this Agreement, unless properly revoked before the completion of the sale of the Shares to the Investor, shall survive the Investor’s death, disability or insolvency, except that the Investor shall have no obligations in the event that this Subscription is rejected by the Company.

i.           The Investor understands that even if the Company becomes a "reporting company" under the Securities Exchange Act of 1934, as amended, the provisions of Rule 144 promulgated under the Securities Act permitting resales of the Shares will not be available for at least one (1) year, and there can be no assurance that the conditions necessary to permit routine sales of the Shares under Rule 144 will ever be satisfied, and, if Rule 144 should become available, routine sales made in reliance on its provisions could be made only in limited amounts and in accordance with the terms and conditions of the Rule.  The Investor further understands that in connection with sales of securities for which Rule 144 is not available, compliance with some other exemption from registration will be required.  The Investor understands that the Company is under no obligation to the undersigned to register the Shares or to comply with the conditions of Rule 144 or take any other action necessary in order to make available any exemption for the sale of the Shares without registration.

j.           The Investor has been advised to consult with the Investor’s own attorney regarding legal, tax, and other matters concerning an investment in the Company and has done so, to the extent the undersigned considers necessary.

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k.           The Investor acknowledges and is aware of the following:

(i)          that the Shares are a speculative investment and involve a high degree of risk of loss by the Investor of the Investor'sentire investment in the Company;

(ii)         that there is no guarantee that the Investor will realize any gain from his or her investment in the Company and that the Investor may lose his or her entire investment;

(iii)        that the Company hasno current plan or intention to issue dividends with respect to the Shares;

(iv)        that there has never been any representation, guarantee or warranty made to the Investor by any broker, the Company, its agents or employees or any other person, expressly or by implication, as to:

(A)           the approximate or exact length of time that the Investor will be required to remain as owner of the Shares; or

(B)           the past performance or experience on the part of the officers or directors of the Company, or of any other person, that will in any way indicate the predictable results of the ownership of the Shares or any such other securities, or of the overall business of the Company;

v)           that the Company may in the future issue additional shares of capital stock in the Company, and that the Investor's interest in the Company may thereby become diluted.

The Investor acknowledges that he or she understands the meaning and legal consequences of the representations, warranties and acknowledgments contained in this Agreement. The Investor confirms that such representations, warranties and acknowledgments are true and accurate as of the date of this Agreement and shall be true and accurate as of the date of delivery of the Funds to the Company and shall survive such delivery. If in any respect such representations and warranties shall not be true and accurate prior to acceptance of this Agreement pursuant to Section 2 of this Agreement, the Investor shall give written notice of such fact to the Company, specifying which representations and warranties are not true and accurate and the reasons therefor.

4.           Indemnification. The Investor acknowledges that he or she understands the meaning and legal consequences of the representations and warranties contained in Section 3 of this Agreement, and the Investoragrees to indemnify, defend and hold harmless the Company and each officer, director, representative and agent of the Company and any person or entity controlling the Company from and against any and all loss, cost, damage or liability (including reasonable attorneys' fees) due to or arising out of a breach of any representation or warranty of the Investor contained in this Agreement.

5.           No Waiver. Notwithstanding any of the representations, warranties, acknowledgments or agreements made in this Agreement bythe Investor, the Investor does not thereby or in any other manner waive any rights granted to the Investor under federal and state securities law.

6.           Transferability. The Investor agrees not to transfer or assign this Agreement, or any of the Investor's interest in this Agreement, and further agrees that any assignment or transfer of the Shares shall be made only in accordance with applicable securities laws and that an appropriate legend with respect thereto may be placed by the Company on any certificate evidencing such Shares.

7.           Revocation. The Investor agrees that he or she shall not cancel, terminate or revoke this Agreement.

8.           Termination of Agreement. If any representation or warranty of the Investor contained in Section 3 of this Agreement shall not be true prior to acceptance of this Agreement, and written notice of such fact has been given by the Investor to the Company, then and in any such event this Agreement shall be null and void and of no further force and effect, and no party shall have any rights against any other party under this Agreement or otherwise, and the Company shall promptly return to the Investor the Funds together with all agreements executed by the Investor.

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9.           Dispute Resolution

a.           All disputes, claims, or controversies arising out of or relating to this Agreement or any other agreement executed and delivered pursuant to this Agreement or the negotiation, validity or performance hereof and thereof or the transactions contemplated hereby and thereby that are not resolved by mutual agreement shall be resolved solely and exclusively by binding arbitration to be conducted before the American Arbitration Association (“AAA”).  If AAA ceases operation, then the parties shall select a comparable organization that provides qualified arbitration services.  The arbitration shall be held in Boston, Massachusetts before a single arbitrator and shall be conducted in accordance with the rules and regulations promulgated by AAA unless specifically modified herein.

b.           The parties covenant and agree that the arbitration hearing shall commence within ninety (90) days of the date on which a written demand for arbitration is filed by any party hereto.  In connection with the arbitration proceeding, the arbitrator shall have the power to order the production of documents by each party and any third-party witnesses.  In addition, each party may take up to three depositions as of right, and the arbitrator may in his or her discretion allow additional depositions upon good cause shown by the moving party.  However, the arbitrator shall not have the power to order the answering of interrogatories or the response to requests for admission.  In connection with any arbitration, each party shall provide to the other, no later than seven (7) business days before the date of the arbitration hearing, the identity of all persons that may testify at the arbitration and a copy of all documents that may be introduced at the arbitration hearing or considered or used by a party’s witness or expert. The arbitrator’s decision and award shall be made and delivered within three (3) months of the selection of the arbitrator. The arbitrator’s decision shall set forth a reasoned basis for any finding of liability or award of damages.  The arbitrator shall not have power to award damages in excess of actual compensatory damages and shall not multiply actual damages or award punitive damages or any other damages that are specifically excluded under this Agreement, and each party hereby irrevocably waives any claim to such damages.

c.           The parties covenant and agree that they will participate in the arbitration in good faith and that they will share equally its costs, except as otherwise provided herein.  The arbitrator may in his or her discretion assess costs and expenses (including the reasonable legal fees and expenses of the prevailing party whether claimant or respondent) against any party to a proceeding.  Any party failing or refusing to comply with an order of the arbitrators shall be liable for costs and expenses, including attorneys’ fees, incurred by the other party in enforcing the award. Nothing in this Section 9 shall prohibit any party from proceeding in court without prior arbitration for the limited purpose of seeking a temporary or permanent injunction to avoid immediate and irreparable harm.  The provisions of this Section 9 shall be enforceable in any court of competent jurisdiction.

d.           Unless otherwise ordered, the parties shall bear their own attorneys’ fees, costs and expenses in connection with the arbitration.  The parties will share equally in the fees and expenses charged by AAA.

e.           Each of the parties hereto irrevocably and unconditionally consents to the exclusive use of AAA to resolve all disputes, claims or controversies arising out of or relating to this Agreement or any other agreement executed and delivered pursuant to this Agreement or the negotiation, validity or performance hereof and thereof or the transactions contemplated hereby and thereby and further consents to the jurisdiction of the federal or state courts of the Commonwealth of Massachusetts for the purposes of enforcing the arbitration provisions of Section 9a of this Agreement.  Each party further irrevocably waives any objection to proceeding before AAA based upon lack of personal jurisdiction or to the laying of venue and further irrevocably and unconditionally waives and agrees not to make a claim in any court that arbitration before AAA has been brought in an inconvenient forum.  Each of the parties hereto hereby consents to service of process by registered mail at the address to which notices are to be given.  Each of the parties hereto agrees that its or his submission to jurisdiction and its or his consent to service of process by mail is made for the express benefit of the other parties hereto.

10.        Miscellaneous

a.           All notices or other communications given or made under this Agreement shall be in writing and shall be delivered or mailed by (a) registered or certified mail, return receipt requested, postage prepaid, or (b) overnight air courier, fees prepaid, to the Investor at his or her address set forth below and to the Company at its address set forth at the outset of this Agreement.

b.           Failure of the Company to exercise any right or remedy under this Agreement or any other agreement between the Company and the Investor, or delay by the Company in exercising the same, will not operate as a waiver of such right or remedy.  No waiver by the Company will be effective unless and until it is in writing and signed on behalf of the Company.

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c.           Notwithstanding the place where this Agreement may be executed by any of the parties hereto, all the terms and provisions hereof shall be construed in accordance with and governed by the laws of the Commonwealth of Massachusetts, without giving effect to its conflict of law principles.

d.           This Agreement is binding upon and inures to the benefit of the parties hereto and their respective heirs, successors and permitted assigns.  This Agreement cannot be assigned, amended or modified by the parties hereto, except by written agreement executed by the parties hereto.

e.           This Agreement may be executed in one or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

f.           If any provision of this Agreement shall for any reason be held invalid or unenforceable, such invalidity or unenforceability shall not affect any other provision hereof and this Agreement shall be construed as if such invalid or unenforceable provision had never been contained herein.

g.           This Agreement constitutes the entire agreement between the parties with respect to the subject matter of this Agreement and may be amended only bya writing executed by all parties.

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IN WITNESS WHEREOF, the undersigned has executed this Agreement on this ___ day of April, 2007.

Manner in which Title is to be held (Please Check One):

1.           ___           Individual

2.           ___           Joint Tenants With Right of Survivorship

3.           ___           Community Property

4.           ___           Tenants in Common

5.           ___           Married with Separate Property

EXECUTION BY NATURAL PERSONS

___________________________________________________________________________

Exact Name(s) in Which Title is to be Held

(If Joint Tenant or Tenants in Common, both persons must

sign and this page must contain all information for both persons).

Signature	Signature
Name (Please Print)	Name (Please Print)
Residence: Number and Street	Residence: Number and Street
City, State, Zip Code	City, State, Zip Code
Social Security Number	Social Security Number
Telephone Number

Accepted this ___ day of April 2007, on behalf of the Company.

AMERICAN DG ENERGY INC.

By:
Name:	Anthony S. Loumidis
Title:	Chief Financial Officer

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EXECUTION BY SUBSCRIBER THAT IS AN ENTITY

(Corporation, Limited Liability Company, Partnership, Trust, Etc.)

________________________________________________________

Name of Entity (Please Print)

Date of Incorporation or Organization:

State of Principal Offices:

Federal Taxpayer Identification Number:

By:

	Title:
Attest:	Address:
(If Entity is a Corporation)

Taxpayer Identification Number

Accepted this ___ day of April 2007, on behalf of the Company.

AMERICAN DG ENERGY INC.

By:
Name:	Anthony S. Loumidis
Title:	Chief Financial Officer

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ACCREDITED INVESTOR QUESTIONNAIRE

Please check the box below that best characterizes the person or entity subscribing for the Shares under the terms of the foregoing Subscription Agreement.

¨ Any natural person whose individual net worth, or joint net worth with that person’s spouse, at the time of his purchase exceeds US $1,000,000;

¨ Any natural person who had an individual income in excess of $200,000 in each of the two most recent years or joint income with that person’s spouse in excess of $300,000 in each of those years and has a reasonable expectation of reaching the same income level in the current year;

¨ Any organization described in Section 501(c)(3) of the Internal Revenue Code, a corporation, a Massachusetts or similar business trust or a partnership, in each case, not formed for the purpose of this investment, with total assets in excess of US $5,000,000;

¨ Any director, executive officer, or general partner of the issuer of the securities being offered or sold, or any director, executive officer, or general partner of a general partner of that issuer;

¨ Any trust with total assets in excess of US $5,000,000, not formed for the specific purpose of acquiring the securities offered, whose purchase is directed by a sophisticated person as described in Rule 506(b)(2)(ii) of the Securities Act of 1933;

¨ Any entity in which all of the equity owners are accredited investors;

¨ Any private business development company as defined in Section 202(a)(22) of the Investment Advisers Act of 1940;

¨ Any Small Business Investment Company licensed by the U.S. Small Business Administration under Section 301(c) or (d) of the Small Business Investment Act of 1958;

¨ Any investment company registered under the Investment Company Act of 1940 or a business development company as defined in Section 2(a)(48) of that Act;

¨ Any bank as defined in Section 3(a)(2) or a savings and loan association or other institution defined in Section 3(a)(5)(A) of the Securities Act of 1933 acting in either an individual or fiduciary capacity;

¨ Any insurance company as defined in Section 2(13) of the Securities Act of 1933;

¨ Any employee benefit plan within the meaning of Title I of the Employee Retirement Income Security Act of 1974 whose investment decision is made by a fiduciary which is either a bank, savings and loan association, insurance company, or registered investment advisor, or whose total assets exceed US $5,000,000, or, if a self-directed plan, a plan whose investment decisions are made solely by persons who are accredited investors;

¨ Any broker or dealer registered pursuant to Section 15 of the Securities Exchange Act of 1934; or

¨ Any plan established and maintained by a state, its political subdivisions, or any agency or instrumentality of a state or its political subdivisions for the benefit of its employees, if such plan has total assets in excess of $5,000,000.

¨ None of the above.

Name of Subscriber:

Social Security Number:

Signature:

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EX-23.2

Exhibit 23.2

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

As independent registered public accountants, we hereby consent to the incorporation by reference in this Registration Statement on Form S-1 of our report dated March 20, 2009, relating to the consolidated financial statements of American DG Energy Inc. which appear in the Company’s Annual Report on Form 10-K for the year ended December 31, 2008 and to the reference to us under the heading “Experts” in the prospectus which is part of this Registration Statement.

/s/ CATURANO AND COMPANY, P.C.

Caturano and Company, P.C.

Boston, Massachusetts

September 30, 2009