SC 13G

                SECURITIES AND EXCHANGE COMMISSION
                      Washington, D.C. 20549


                          SCHEDULE 13G

             Under the Securities Exchange Act of 1934
                       (Amendment No. )*


                          Active Power, Inc.
               -----------------------------------------
                           (Name of Issuer)


                      Common Stock, $0.001 par value
               -----------------------------------------
                      (Title of Class of Securities)


                            00504W100
                -----------------------------------------
                            (CUSIP Number)


                               December 31, 2000
                -----------------------------------------
          (Date of Event Which Requires Filing of this Statement)


      Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

      [ ] Rule 13d-1(b)

      [x] Rule 13d-1(c)

      [ ] Rule 13d-1(d)

      *The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which
would alter the disclosures provided in a prior cover page.

      The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities
Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that
section of the Act but shall be subject to all other provisions of the Act
(however, see the Notes).



                                  CUSIP No. 00504W100


1    NAME OF REPORTING PERSON
     I.R.S. Identification No. of above person (entities only).

      Rho Management Company, Inc.


2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                       (a) [  ]
                                                       (b) [  ]

3    SEC USE ONLY


4    CITIZENSHIP OR PLACE OF ORGANIZATION

      New York


     NUMBER OF SHARES BENEFICIALLY OWNED BY
     EACH REPORTING PERSON WITH:

      5     SOLE VOTING POWER

            2,220,255 Shares

      6     SHARED VOTING POWER

            0 Shares


      7     SOLE DISPOSITIVE POWER

            2,220,255 Shares


      8     SHARED DISPOSITIVE POWER

            0 Shares


9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      2,220,255 Shares



10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
      (SEE INSTRUCTIONS)



11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

      5.7%


12   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

      CO/IA




                                  CUSIP No. 00504W100


1    NAME OF REPORTING PERSON
     I.R.S. Identification No. of above person (entities only).

     Joshua Ruch


2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                       (a) [  ]
                                                       (b) [  ]

3    SEC USE ONLY


4    CITIZENSHIP OR PLACE OF ORGANIZATION

     Republic of South Africa


     NUMBER OF SHARES BENEFICIALLY OWNED BY
     EACH REPORTING PERSON WITH:

      5     SOLE VOTING POWER

            52,594 Shares

      6     SHARED VOTING POWER

            2,220,255 Shares


      7     SOLE DISPOSITIVE POWER

            52,594 Shares


      8     SHARED DISPOSITIVE POWER

            2,220,255 Shares


9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      2,272,849 Shares



10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
      (SEE INSTRUCTIONS)



11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

      5.9%


12   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

      IN




      This Statement on Schedule 13G relates to shares of Common Stock (the
"Shares") of Active Power, Inc. (the "Company") beneficially owned by Rho
Management Company, Inc. and Joshua Ruch, as follows below.


      Item 1(a)  Name of issuer:  Active Power, Inc., a Delaware corporation
(the "Company").

      Item 1(b)  Address of issuer's principal executive offices: 11525
Stonehollow Drive, Suite 110, Austin, Texas 78578.


     Item 2.      Identity of Persons Filing.

      (a)  This Statement is being filed by Rho Management Company, Inc.
("Rho"), a New York corporation, and Joshua Ruch.  Rho serves as investment
advisor to a number of investment vehicles, and as such may be deemed to
exercise investment and voting control over Shares registered in the names of
such vehicles.  Joshua Ruch, a controlling stockholder of Rho, may be deemed
to have shared authority over the Shares reported by Rho herein, and to
exercise independent investment and voting authority over certain Shares.

      (b)-(c)  Rho is a New York corporation, with its address at 152 West
57th Street, 23rd Floor, New York, New York 10019.

      Mr. Ruch is a citizen of the Republic of South Africa, with his address
c/o Rho, 152 West 57th Street, 23rd Floor, New York, New York 10019.

      2(d)  Title of class of securities: [Common Stock]

      2(e)  CUSIP No.:   00504W100

      Item 3.  If this statement is filed pursuant to Rule 13d-1(b) or Rule
13d-2(b) or (c), check whether the person filing is a:

      (a) [ ] Broker or dealer registered under Section 15 of the Exchange
Act.

      (b) [ ] Bank as defined in section 3(a)(6) of the Exchange Act.

      (c) [ ] Insurance company as defined in section 3(a)(19) of the Exchange
Act.

      (d) [ ] Investment company registered under section 8 of the Investment
Company Act.

      (e) [ ] An investment adviser in accordance with Rule
13d-1(b)(1)(ii)(E);

      (f) [ ] An employee benefit plan or endowment fund in accordance with
Rule 13d-1(b)(1)(ii)(F);

      (g) [ ] A parent holding company or control person in accordance with
Rule 13d-1(b)(1)(ii)(G);

      (h) [ ] A savings associations as defined in Section 3(b) of the Federal
Deposit Insurance Act;

      (i) [ ] A church plan that is excluded from the definition of an
investment company under section 3(c)(14) of the Investment Company Act;

      (j) [ ] Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

      If this statement is filed pursuant to Rule 13d-1(c), check this box.
[x]


      Item 4.  Ownership

      See cover page for each reporting person.

      As the ultimate holder of voting and investment authority over the
Shares owned by its investment advisory clients, Rho may be deemed, for
purposes of Rule 13d-3 under the Securities Exchange Act of 1934, as amended,
to be the beneficial owner of 2,220,255 Shares reported hereby, constituting
5.7% of the Company's outstanding shares reported as of the reporting event
date.

      Joshua Ruch is a controlling stockholder of Rho, and as such may be
deemed to have shared control over the Shares reported for Rho.  Mr. Ruch
additionally exercises investment and voting control over certain other Shares
held in personal accounts, over which he may be deemed to have sole beneficial
ownership.  Mr. Ruch accordingly may be deemed, for purposes of Rule 13d-3
under the Securities Exchange Act of 1934, as amended, to be the beneficial
owner of 2,272,849 Shares reported hereby,
constituting 5.9% of the Company's outstanding shares reported as of the
reporting event date.  Other than Shares in which he has a pecuniary interest,
Mr. Ruch disclaims beneficial ownership of the Shares reported by this
Statement.


      Item 5.  Ownership of 5 Percent or Less of a Class.

      If this statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial owner of more than
five percent of the class of securities, check the following:      [ ]


      Item 6.  Ownership of More than 5 Percent on Behalf of Another Person.

      Not applicable.


      Item 7.  Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on By the Parent Holding Company.

      Not applicable.


      Item 8.  Identification and Classification of Members of the Group.


      Not applicable.


      Item 9.  Notice of Dissolution of Group.


      Not applicable.


      Item 10. Certifications

      By signing below I certify that, to the best of my knowledge and belief,
the securities referred to above were not acquired and are not held for the
purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.




                                   SIGNATURE

      After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


Dated:  February 14, 2001.


RHO MANAGEMENT COMPANY, INC.

    By: /s/ Joshua Ruch
    --------------------------
    Name: Joshua Ruch
    Title: President


JOSHUA RUCH

      /s/ Joshua Ruch
    --------------------------
      Name: Joshua Ruch

EX-99

                                   EXHIBIT A
                            JOINT FILING AGREEMENT

Pursuant to Rule 13d-1(k)(1) promulgated under the Securities Exchange Act of
1934, the undersigned agree to the joint filing of a Statement on Schedule 13G
(including any and all amendments thereto, and any filing on Schedule 13D
relating to the same investment) with respect to the shares of common stock,
par value $0.001 per share, of Active Power, Inc., and further agree that this
Joint Filing Agreement be included as an Exhibit thereto.  In addition, each
party to this Agreement expressly authorizes each other party to this
Agreement to file on its behalf any and all amendments to such Statement.

Dated:  February 14, 2001.


RHO MANAGEMENT COMPANY, INC.

    By: /s/ Joshua Ruch
    --------------------------
    Name: Joshua Ruch
    Title: President


JOSHUA RUCH

      /s/ Joshua Ruch
    --------------------------
      Name: Joshua Ruch