SEC FORM 4

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

PEARL FRANK H

(Last)

(First)

(Middle)

C/O PERSEUS CAPITAL, L.L.C.

2099 PENNSYLVANIA AVENUE, NW, SUITE 900

(Street)

WASHINGTON

20006

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
BEACON POWER CORP [ BCON ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
11/21/2005

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	11/21/2005		J⁽¹⁾		3,211,174	D	⁽¹⁾	3,743,558	I⁽²⁾⁽³⁾	Through Perseus 2000 Expansion, L.L.C. and also held directly
Common Stock	11/22/2005		J⁽⁴⁾⁽⁵⁾		1,190,476	D	⁽⁴⁾⁽⁵⁾	3,743,558	I⁽²⁾⁽⁶⁾	Through Perseus 2000 Expansion, L.L.C. and also held directly

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Warrant	$1.008	11/22/2005		J⁽⁴⁾⁽⁵⁾			138,636	06/13/2005	06/13/2010	Common Stock	138,636	⁽⁴⁾⁽⁵⁾	0	I⁽²⁾⁽⁶⁾	Through Perseus 2000 Expansion, L.L.C.
Warrant	$1.008	11/22/2005		J⁽⁴⁾⁽⁵⁾			138,636	07/21/2005	07/21/2010	Common Stock	138,636	⁽⁴⁾⁽⁵⁾	0	I⁽²⁾⁽⁶⁾	Through Perseus 2000 Expansion, L.L.C.

Explanation of Responses:

1. Distribution of shares from Perseus Capital, L.L.C. to its members based on its governing documents. The Reporting Person is the Chairman of Perseus, L.L.C., who through certain entities controls Perseus Capital, L.L.C., and also is a member of Perseus Investors Group, L.L.C., which in turn is a member of Perseus Capital, L.L.C.

2. The Reporting Person controls entities that have director representation on the Issuer's board of directors and which entites are deemed to be directors of the Issuer by deputization.

3. The Reporting Person is the Chairman of Perseus, L.L.C., who through certain entities controls Perseus Capital, L.L.C. As reported, Perseus Capital, L.L.C. distributed 3,502,351 shares of the reported securities to its members. The Reporting Person is also a member of Perseus Investors Group, L.L.C., which is a member of Perseus Capital, L.L.C. As reported, Perseus Investors Group, L.L.C. received from Perseus Capital, L.L.C. 291,177 of the 3,502,351 shares of the reported securities distributed by Perseus Capital, L.L.C. The Reporting Person disclaims beneficial ownership of the reported securities, except to the extent of his pecuniary interest therein.

4. As previously reported, on April 22, 2005, Perseus 2000 Expansion, L.L.C., an investment fund affiliated with the reporting person, entered into an investment agreement with Beacon Power Corp. ("Beacon"). Pursuant to the agreement, among other things, Perseus 2000 Expansion was granted an option to require Beacon to purchase up to three tranches of shares of preferred stock of NxtPhase T&D Corp., a Canadian corporation ("NxtPhase"), if Perseus 2000 Expansion funded such purchase by acquiring shares of and warrants to acquire Beacon common stock in a dollar amount equal to the amount of shares of NxtPhase preferred stock that Beacon was to purchase from NxtPhase. Beacon and NxtPhase had entered into an Arrangement Agreement on April 22, 2005, pursuant to which Beacon would acquire NxtPhase. In the event the Arrangement Agreement was terminated, the issuance by Beacon to Perseus 2000 Expansion would be rescinded and Beacon would transfer its shares of NxtPhase to Perseus 2000 Expansion.

5. On November 22, 2005, Beacon and NxtPhase terminated the Arrangement Agreement. As a result thereof, the shares of Beacon common stock and warrants to purchase Beacon common stock referenced herein have been rescinded, and Perseus 2000 Expansion has instead received shares of NxtPhase preferred stock.

6. The Reporting Person disclaims beneficial ownership of the reported securities, except to the extent of his pecuniary interest therein, if any.

Remarks:

	By: Rodd Macklin, Attorney-in-Fact	11/22/2005
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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