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                                                                   EXHIBIT 10.10

                         SATCON TECHNOLOGY CORPORATION

                            1996 STOCK OPTION PLAN

                                April 29, 1996


1.   Purpose. 
     -------

     The purpose of this plan (the "Plan") is to secure for SatCon Technology
Corporation (the "Company") and its shareholders the benefits arising from
capital stock ownership by employees, officers and directors of, and consultants
or advisors to, the Company and its parent and subsidiary corporations who are
expected to contribute to the Company's future growth and success. Except where
the context otherwise requires, the term "Company" shall include the parent and
all present and future subsidiaries of the Company as defined in Sections 424(e)
and 424(f) of the Internal Revenue Code of 1986, as amended or replaced from
time to time (the "Code"). Those provisions of the Plan which make express
reference to Section 422 shall apply only to Incentive Stock Options (as that
term is defined in the Plan).

2.   Type of Options and Administration. 
     ----------------------------------

     (a)  Types of Options.  Options granted pursuant to the Plan may be either
          ----------------
incentive stock options ("Incentive Stock Options") meeting the requirements of
Section 422 of the Code or Non-Statutory Options which are not intended to meet
the requirements of Section 422 of the Code ("Non-Statutory Options").

     (b)  Administration.  
          --------------

          (i)  The Plan will be administered by the Board of Directors of the
Company, whose construction and interpretation of the terms and provisions of
the Plan shall be final and conclusive. The Board of Directors may in its sole
discretion grant options to purchase shares of the Company's Common Stock
("Common Stock") and issue shares upon exercise of such options as provided in
the Plan. The Board shall have authority, subject to the express provisions of
the Plan, to construe the respective option agreements and the Plan, to
prescribe, amend and rescind rules and regulations relating to the Plan, to
determine the terms and provisions of the respective option agreements, which
need not be identical, and to make all other determinations which are, in the
judgment of the Board of Directors, necessary or desirable for the
administration of the Plan. The Board of Directors may correct any defect,
supply any omission or reconcile any inconsistency in the Plan or in any option
agreement in the manner and to the extent it shall deem expedient to carry the
Plan into effect and it shall be the sole and final judge of such expediency. No
director or person acting pursuant to authority
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delegated by the Board of Directors shall be liable for any action or
determination under the Plan made in good faith.

          (ii) The Board of Directors may, to the full extent permitted by or
consistent with applicable laws or regulations and Section 3(b) of this Plan
delegate any or all of its powers under the Plan to a committee (the
"Committee") appointed by the Board of Directors, and if the Committee is so
appointed all references to the Board of Directors in the Plan shall mean and
relate to such Committee.

     (c)  Applicability of Rule 16b-3.  Those provisions of the Plan which make
          ---------------------------
express reference to Rule 16b-3 promulgated under the Securities Exchange Act of
1934 (the "Exchange Act"), or any successor rule ("Rule 16b-3"), or which are
required in order for certain option transactions to qualify for exemption under
Rule 16b-3, shall apply only to such persons as are required to file reports
under Section 16(a) of the Exchange Act (a "Reporting Person").

3.   Eligibility. 
     -----------

     (a)  General.  Options may be granted to persons who are, at the time of
          -------
grant, employees, officers or directors of, or consultants or advisors to, the
Company; provided, that the class of employees to whom Incentive Stock Options
         --------
may be granted shall be limited to all employees of the Company. A person who
has been granted an option may, if he or she is otherwise eligible, be granted
additional options if the Board of Directors shall so determine. Subject to
adjustment as provided in Section 15 below, the maximum number of shares with
respect to which options may be granted to any employee under the Plan shall not
exceed 100,000 shares of common stock during any calendar year. For the purpose
of calculating such maximum number, (a) an option shall continue to be treated
as outstanding notwithstanding its repricing, cancellation or expiration and (b)
the repricing of an outstanding option or the issuance of a new option in
substitution for a cancelled option shall be deemed to constitute the grant of a
new additional option separate from the original grant of the option that is
repriced or cancelled.

     (b)  Grant of Options to Directors and Officers.  From and after the
          ------------------------------------------
registration of the Common Stock of the Company under the Exchange Act, the
selection of a director or an officer (as the terms "director" and "officer" are
defined for purposes of Rule 16b-3) as a recipient of an option, the timing of
the option grant, the exercise price of the option and the number of shares
subject to the option shall be determined either (i) by the Board of Directors,
of which all members shall be "disinterested persons" (as hereinafter defined),
or (ii) by two or more directors having full authority to act in the matter,
each of whom shall be a "disinterested person." For the purposes of the Plan,
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a director shall be deemed to be a "disinterested person" only if such person
qualifies as a "disinterested person" within the meaning of Rule 16b-3, as such
term is interpreted from time to time.

4.   Stock Subject to Plan. 
     ---------------------

     Subject to adjustment as provided in Section 15 below, the maximum number
of shares of Common Stock which may be issued and sold under the Plan is 300,000
shares. If an option granted under the Plan shall expire or terminate for any
reason without having been exercised in full, the unpurchased shares subject to
such option shall again be available for subsequent option grants under the
Plan. If shares issued upon exercise of an option under the Plan are tendered to
the Company in payment of the exercise price of an option granted under the
Plan, such tendered shares shall again be available for subsequent option grants
under the Plan; provided, that in no event shall such shares be made available
for issuance to Reporting Persons or pursuant to exercise of Incentive Stock
Options.

5.   Forms of Option Agreements.  
     --------------------------

     As a condition to the grant of an option under the Plan, each recipient of
an option shall execute an option agreement in such form not inconsistent with
the Plan as may be approved by the Board of Directors. Such option agreements
may differ among recipients.

6.   Purchase Price. 
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     (a)  General.  Subject to Section 3(b), the purchase price per share of
          -------
stock deliverable upon the exercise of an option shall be determined by the
Board of Directors, provided, however, that in the case of an Incentive Stock
                    --------  -------
Option, the exercise price shall not be less than 100% of the fair market value
of such stock, as determined by the Board of Directors, at the time of grant of
such option, or less than 110% of such fair market value in the case of options
described in Section 11(b).

     (b)  Payment of Purchase Price.  Options granted under the Plan may provide
          -------------------------
for the payment of the exercise price by delivery of cash or a check to the
order of the Company in an amount equal to the exercise price of such options,
or, to the extent provided in the applicable option agreement, (i) by delivery
to the Company of shares of Common Stock of the Company already owned by the
optionee having a fair market value equal in amount to the exercise price of the
options being exercised or (ii) by any other means (including, without
limitation, by delivery of a promissory note of the optionee payable on such
terms as are specified by the Board of Directors) which the Board of Directors
determines are consistent with the purpose of the Plan and with applicable laws
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and regulations (including, without limitation, the provisions of Regulation T
promulgated by the Federal Reserve Board). The fair market value of any shares
of the Company's Common Stock or other non-cash consideration which may be
delivered upon exercise of an option shall be determined by the Board of
Directors.

7.   Option Period. 
     -------------

     Each option and all rights thereunder shall expire on such date as shall be
set forth in the applicable option agreement, except that, in the case of an
Incentive Stock Option, such date shall not be later than ten years after the
date on which the option is granted and, in all cases, options shall be subject
to earlier termination as provided in the Plan.

8.   Exercise of Options. 
     -------------------

     Each option granted under the Plan shall be exercisable either in full or
in installments at such time or times and during such period as shall be set
forth in the agreement evidencing such option, subject to the provisions of the
Plan.

9.   Nontransferability of Options. 
     -----------------------------

     Options shall not be assignable or transferable by the person to whom they
are granted, either voluntarily or by operation of law, except by will or the
laws of descent and distribution, and, during the life of the optionee, shall be
exercisable only by the optionee; provided, however, that Non-Statutory Options
may be transferred pursuant to a qualified domestic relations order (as defined
in Rule 16b-3).

10.  Effect of Termination of Employment or Other Relationship.
     ---------------------------------------------------------

     Except as provided in Section 11(d) with respect to Incentive Stock
Options, and subject to the provisions of the Plan, the Board of Directors shall
determine the period of time during which an optionee may exercise an option
following (i) the termination of the optionee's employment or other relationship
with the Company or (ii) the death or disability of the optionee. Such periods
shall be set forth in the agreement evidencing such option.

11.  Incentive Stock Options.
     -----------------------

     Options granted under the Plan which are intended to be Incentive Stock
Options shall be subject to the following additional terms and conditions:
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     (a)  Express Designation.  All Incentive Stock Options granted under the
          -------------------
Plan shall, at the time of grant, be specifically designated as such in the
option agreement covering such Incentive Stock Options.

     (b)  10% Shareholder.  If any employee to whom an Incentive Stock Option is
          ---------------
to be granted under the Plan is, at the time of the grant of such option, the
owner of stock possessing more than 10% of the total combined voting power of
all classes of stock of the Company (after taking into account the attribution
of stock ownership rules of Section 424(d) of the Code), then the following
special provisions shall be applicable to the Incentive Stock Option granted to
such individual:

          (i)    The purchase price per share of the Common Stock subject to
     such Incentive Stock Option shall not be less than 110% of the fair market
     value of one share of Common Stock at the time of grant; and

          (ii)   the option exercise period shall not exceed five years from the
     date of grant.

     (c)  Dollar Limitation.  For so long as the Code shall so provide, options
          -----------------
granted to any employee under the Plan (and any other incentive stock option
plans of the Company) which are intended to constitute Incentive Stock Options
shall not constitute Incentive Stock Options to the extent that such options, in
the aggregate, become exercisable for the first time in any one calendar year
for shares of Common Stock with an aggregate fair market value (determined as of
the respective date or dates of grant) of more than $100,000.

     (d)  Termination of Employment, Death or Disability.  No Incentive Stock
          ----------------------------------------------
Option may be exercised unless, at the time of such exercise, the optionee is,
and has been continuously since the date of grant of his or her option, employed
by the Company, except that:

          (i)    an Incentive Stock Option may be exercised within the period of
     three months after the date the optionee ceases to be an employee of the
     Company (or within such lesser period as may be specified in the applicable
     option agreement), provided, that the agreement with respect to such option
                        -------- 
     may designate a longer exercise period and that the exercise after such
     three-month period shall be treated as the exercise of a non-statutory
     option under the Plan;

          (ii)   if the optionee dies while in the employ of the Company, or
     within three months after the optionee ceases to be such an employee, the
     Incentive Stock Option may be exercised by the person to whom it is
     transferred by will or
<PAGE>
 
     the laws of descent and distribution within the period of one year after
     the date of death (or within such lesser period as may be specified in the
     applicable option agreement); and

          (iii)  if the optionee becomes disabled (within the meaning of Section
     22(e)(3) of the Code or any successor provision thereto) while in the
     employ of the Company, the Incentive Stock Option may be exercised within
     the period of one year after the date the optionee ceases to be such an
     employee because of such disability (or within such lesser period as may be
     specified in the applicable option agreement).

For all purposes of the Plan and any option granted hereunder, "employment"
shall be defined in accordance with the provisions of Section 1.421-7(h) of the
Income Tax Regulations (or any successor regulations). Notwithstanding the
foregoing provisions, no Incentive Stock Option may be exercised after its
expiration date.

12.  Additional Provisions.
     ---------------------

     (a)  Additional Option Provisions.  The Board of Directors may, in its sole
          ----------------------------
discretion, include additional provisions in option agreements covering options
granted under the Plan, including without limitation restrictions on transfer,
repurchase rights, commitments to pay cash bonuses, to make, arrange for or
guaranty loans or to transfer other property to optionees upon exercise of
options, or such other provisions as shall be determined by the Board of
Directors; provided that such additional provisions shall not be inconsistent
           -------- ----
with any other term or condition of the Plan and such additional provisions
shall not cause any Incentive Stock Option granted under the Plan to fail to
qualify as an Incentive Stock Option within the meaning of Section 422 of the
Code.

     (b)  Acceleration, Extension, Etc.  The Board of Directors may, in its sole
          ----------------------------
discretion, (i) accelerate the date or dates on which all or any particular
option or options granted under the Plan may be exercised or (ii) extend the
dates during which all, or any particular, option or options granted under the
Plan may be exercised.

13.  General Restrictions.
     --------------------

     (a)  Investment Representations.  The Company may require any person to
          --------------------------
whom an option is granted, as a condition of exercising such option, to give
written assurances in substance and form satisfactory to the Company to the
effect that such person is acquiring the Common Stock subject to the option for
his or her own account for investment and not with any present intention of
selling or otherwise distributing the same, and to such other effects as the
Company deems necessary or appropriate in order to
<PAGE>
 
comply with federal and applicable state securities laws, or with covenants or
representations made by the Company in connection with any public offering of
its Common Stock.

     (b)  Compliance With Securities Laws.  Each option shall be subject to the
          -------------------------------
requirement that if, at any time, counsel to the Company shall determine that
the listing, registration or qualification of the shares subject to such option
upon any securities exchange or under any state or federal law, or the consent
or approval of any governmental or regulatory body, or that the disclosure of
non-public information or the satisfaction of any other condition is necessary
as a condition of, or in connection with, the issuance or purchase of shares
thereunder, such option may not be exercised, in whole or in part, unless such
listing, registration, qualification, consent or approval, or satisfaction of
such condition shall have been effected or obtained on conditions acceptable to
the Board of Directors. Nothing herein shall be deemed to require the Company to
apply for or to obtain such listing, registration or qualification, or to
satisfy such condition.

14.  Rights as a Shareholder.
     -----------------------

     The holder of an option shall have no rights as a shareholder with respect
to any shares covered by the option (including, without limitation, any rights
to receive dividends or non-cash distributions with respect to such shares)
until the date of issue of a stock certificate to him or her for such shares. No
adjustment shall be made for dividends or other rights for which the record date
is prior to the date such stock certificate is issued.

15.  Adjustment Provisions for Recapitalizations and Related Transactions.
     --------------------------------------------------------------------

     (a)  General.  If, through or as a result of any merger, consolidation,
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sale of all or substantially all of the assets of the Company, reorganization,
recapitalization, reclassification, stock dividend, stock split, reverse stock
split or other similar transaction, (i) the outstanding shares of Common Stock
are increased, decreased or exchanged for a different number or kind of shares
or other securities of the Company, or (ii) additional shares or new or
different shares or other securities of the Company or other non-cash assets are
distributed with respect to such shares of Common Stock or other securities, an
appropriate and proportionate adjustment may be made in (x) the maximum number
and kind of shares reserved for issuance under the Plan, (y) the number and kind
of shares or other securities subject to any then outstanding options under the
Plan, and (z) the price for each share subject to any then outstanding options
under the Plan, without changing the aggregate purchase price as to which such
options remain exercisable. Notwithstanding the foregoing, no
<PAGE>
 
adjustment shall be made pursuant to this Section 15 if such adjustment would
cause the Plan to fail to comply with Section 422 of the Code.

     (b)  Board Authority to Make Adjustments.  Any adjustments under this
          -----------------------------------
Section 15 will be made by the Board of Directors, whose determination as to
what adjustments, if any, will be made and the extent thereof will be final,
binding and conclusive. No fractional shares will be issued under the Plan on
account of any such adjustments.

16.  Merger, Consolidation, Asset Sale, Liquidation, etc.
     ---------------------------------------------------

     (a)  General.  In the event of a consolidation or merger or sale of all or
          -------
substantially all of the assets of the Company in which outstanding shares of
Common Stock are exchanged for securities, cash or other property of any other
corporation or business entity or in the event of a liquidation of the Company,
the Board of Directors of the Company, or the board of directors of any
corporation assuming the obligations of the Company, may, in its discretion,
take any one or more of the following actions, as to outstanding options: (i)
provide that such options shall be assumed, or equivalent options shall be
substituted, by the acquiring or succeeding corporation (or an affiliate
thereof), provided that any such options substituted for Incentive Stock Options
          --------
shall meet the requirements of Section 424(a) of the Code, (ii) upon written
notice to the optionees, provide that all unexercised options will terminate
immediately prior to the consummation of such transaction unless exercised by
the optionee within a specified period following the date of such notice, (iii)
in the event of a merger under the terms of which holders of the Common Stock of
the Company will receive upon consummation thereof a cash payment for each share
surrendered in the merger (the "Merger Price"), make or provide for a cash
payment to the optionees equal to the difference between (A) the Merger Price
times the number of shares of Common Stock subject to such outstanding options
(to the extent then exercisable at prices not in excess of the Merger Price) and
(B) the aggregate exercise price of all such outstanding options in exchange for
the termination of such options, and (iv) provide that all or any outstanding
options shall become exercisable in full immediately prior to such event.

     (b)  Substitute Options.  The Company may grant options under the Plan in
          ------------------
substitution for options held by employees of another corporation who become
employees of the Company, or a subsidiary of the Company, as the result of a
merger or consolidation of the employing corporation with the Company or a
subsidiary of the Company, or as a result of the acquisition by the Company, or
one of its subsidiaries, of property or stock of the employing corporation. The
Company may direct that substitute options be
<PAGE>
 
granted on such terms and conditions as the Board of Directors considers
appropriate in the circumstances.

17.  No Special Employment Rights.
     ----------------------------

     Nothing contained in the Plan or in any option shall confer upon any
optionee any right with respect to the continuation of his or her employment by
the Company or interfere in any way with the right of the Company at any time to
terminate such employment or to increase or decrease the compensation of the
optionee.

18.  Other Employee Benefits.  
     -----------------------

     Except as to plans which by their terms include such amounts as
compensation, the amount of any compensation deemed to be received by an
employee as a result of the exercise of an option or the sale of shares received
upon such exercise will not constitute compensation with respect to which any
other employee benefits of such employee are determined, including, without
limitation, benefits under any bonus, pension, profit-sharing, life insurance or
salary continuation plan, except as otherwise specifically determined by the
Board of Directors.

19.  Amendment of the Plan.
     ---------------------

     (a)  The Board of Directors may at any time, and from time to time, modify
or amend the Plan in any respect, except that if at any time the approval of the
shareholders of the Company is required under Section 422 of the Code or any
successor provision with respect to Incentive Stock Options, or under Rule 16b-
3, the Board of Directors may not effect such modification or amendment without
such approval.

     (b)  The termination or any modification or amendment of the Plan shall
not, without the consent of an optionee, affect his or her rights under an
option previously granted to him or her. With the consent of the optionee
affected, the Board of Directors may amend outstanding option agreements in a
manner not inconsistent with the Plan. The Board of Directors shall have the
right to amend or modify (i) the terms and provisions of the Plan and of any
outstanding Incentive Stock Options granted under the Plan to the extent
necessary to qualify any or all such options for such favorable federal income
tax treatment (including deferral of taxation upon exercise) as may be afforded
incentive stock options under Section 422 of the Code and (ii) the terms and
provisions of the Plan and of any outstanding option to the extent necessary to
ensure the qualification of the Plan under Rule 16b-3.

20.  Withholding.
     -----------

     (a)  The Company shall have the right to deduct from payments of any kind
otherwise due to the optionee any federal, state or
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local taxes of any kind required by law to be withheld with respect to any
shares issued upon exercise of options under the Plan. Subject to the prior
approval of the Company, which may be withheld by the Company in its sole
discretion, the optionee may elect to satisfy such obligations, in whole or in
part, (i) by causing the Company to withhold shares of Common Stock otherwise
issuable pursuant to the exercise of an option or (ii) by delivering to the
Company shares of Common Stock already owned by the optionee. The shares so
delivered or withheld shall have a fair market value equal to such withholding
obligation. The fair market value of the shares used to satisfy such withholding
obligation shall be determined by the Company as of the date that the amount of
tax to be withheld is to be determined. An optionee who has made an election
pursuant to this Section 20(a) may only satisfy his or her withholding
obligation with shares of Common Stock which are not subject to any repurchase,
forfeiture, unfulfilled vesting or other similar requirements.

     (b)  Notwithstanding the foregoing, in the case of a Reporting Person, no
election to use shares for the payment of withholding taxes shall be effective
unless made in compliance with any applicable requirements of Rule 16b-3 (unless
it is intended that the transaction not qualify for exemption under Rule 16b-3).

21.  Cancellation and New Grant of Options, Etc.
     ------------------------------------------

     The Board of Directors shall have the authority to effect, at any time and
from time to time, with the consent of the affected optionees, (i) the
cancellation of any or all outstanding options under the Plan and the grant in
substitution therefor of new options under the Plan covering the same or
different numbers of shares of Common Stock and having an option exercise price
per share which may be lower or higher than the exercise price per share of the
cancelled options or (ii) the amendment of the terms of any and all outstanding
options under the Plan to provide an option exercise price per share which is
higher or lower than the then-current exercise price per share of such
outstanding options.

22.  Effective Date and Duration of the Plan.
     ---------------------------------------

     (a)  Effective Date.  The Plan shall become effective when adopted by the
          --------------
Board of Directors, but no option granted under the Plan shall become
exercisable unless and until the Plan shall have been approved by the Company's
shareholders. If such shareholder approval is not obtained within twelve months
after the date of the Board's adoption of the Plan, options previously granted
under the Plan shall not vest and shall terminate and no options shall be
granted thereafter. Amendments to the Plan not requiring shareholder approval
shall become effective when adopted by the Board of Directors; amendments
requiring shareholder approval (as provided in Section 19) shall become
effective when adopted by the
<PAGE>
 
Board of Directors, but no option granted after the date of such amendment shall
become exercisable (to the extent that such amendment to the Plan was required
to enable the Company to grant such option to a particular person) unless and
until such amendment shall have been approved by the Company's shareholders. If
such shareholder approval is not obtained within twelve months of the Board's
adoption of such amendment, any options granted on or after the date of such
amendment shall terminate to the extent that such amendment was required to
enable the Company to grant such option to a particular optionee. Subject to
this limitation, options may be granted under the Plan at any time after the
effective date and before the date fixed for termination of the Plan.

     (b)  Termination.  Unless sooner terminated in accordance with Section 16,
          -----------
the Plan shall terminate upon the close of business on the day next preceding
the tenth anniversary of the date of its adoption by the Board of Directors.
Options outstanding on such date shall continue to have force and effect in
accordance with the provisions of the instruments evidencing such options.

23.  Provision for Foreign Participants.
     ----------------------------------

     The Board of Directors may, without amending the Plan, modify awards or
options granted to participants who are foreign nationals or employed outside
the United States to recognize differences in laws, rules, regulations or
customs of such foreign jurisdictions with respect to tax, securities, currency,
employee benefit or other matters.

                                       Adopted by the Board of Directors on
                                       April 29, 1996.



                                       Approved by Stockholders on 
                                       _____________, 1996.