<PAGE>
                                                                   Exhibit 10.66

                      TEST REPORTING, ENGINEERING SERVICES
                                       AND
                            FIELD SERVICES AGREEMENT
                                      AMONG
                ECO FUEL CELLS, LLC, ENERGY CO-OPPORTUNITY, INC.
                                       AND
                                  H POWER CORP.

This Test Reporting, Engineering Services and Field Services Agreement
("Agreement") is entered into this 10 day of April, 2002 (the "Effective Date"),
among H Power Corp., 1373 Broad Street, Clifton, NJ 07013; H Power Enterprises
of Canada, Inc. (together "H Power"); and ECO Fuel Cells, LLC ("EFC") and Energy
Co-Opportunity, Inc. ("ECO") both of 2201 Cooperative Way, Herndon, VA 20171.
These parties are referred to herein singularly as "Party" and collectively as
"Parties." Defined terms used, but not otherwise defined herein, shall have the
respective meanings set forth in the Second Amended and Restated Fuel Cell
Product Operating Agreement, dated April 10, 2002 among the Parties (the
"Operating Agreement").


                                    RECITALS

WHEREAS: The Parties have entered into the Operating Agreement to, among other
things, further encourage the marketing of H Power's Fuel Cell Products, to
provide the Parties with additional marketing and distribution opportunities,
and to explore other products and services offered by H Power including new fuel
cell products and applications; and

WHEREAS: EFC's expertise in distributed generation equipment and installation is
transferable to the ongoing installation and maintenance of H Power's Fuel Cell
Products; and

WHEREAS: H Power desires to secure EFC's expertise in support, installation,
maintenance and other areas to help establish its customer service systems for
Fuel Cell Products; and

WHEREAS: The Parties have been engaged in a Fuel Cell testing program ("Testing
Program") under which H Power's Alpha and Beta Fuel Cell Power Systems have been
tested by EFC and its Cooperative Members in field operating conditions since
2000; and this Testing Program has developed valuable experience and data that
can be used to improve the design and the performance of Fuel Cell Power
Systems; and

WHEREAS: H Power wishes to have EFC collect, review and evaluate data concerning
the Testing Program and prepare a "Report" as defined herein, that will assist H
Power in its future Fuel Cell development plans and operations; and

WHEREAS: EFC has specific expertise in the ongoing Testing Program and also with
distributed generation equipment and installation that makes it exceptionally
qualified to evaluate such field results and to prepare a Report on the Testing
Program as described in this Agreement;

NOW, THEREFORE, in consideration of the promises herein and other valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, the
Parties hereby agree as follows:

      1.    TEST REPORTING AND ENGINEERING SERVICES.

            a.    IMPROVEMENTS IN DESIGN AND PERFORMANCE. EFC will review,
                  evaluate and prepare a written report for H Power summarizing
                  the test results and information

----------
Certain portions of this exhibit have been omitted pursuant to a request for
confidential treatment. The omitted materials have been filed separately with
the Securities and Exchange Commission.

                                  Page 1 of 10

<PAGE>

                  on the Testing Program and identify areas of improvement for
                  both the design, performance, and similar issues involving the
                  Fuel Cell Power Systems Testing Program (the "Report"). EFC
                  will submit a proposed outline of the Report to H Power by May
                  15, 2002.

            b.    SITE AND INSTALLATION EVALUATION. EFC will evaluate the site
                  preparation and other installation costs and the installation
                  requirements of the Testing Program to determine what savings
                  and improvements could be made to simplify installation of
                  future Fuel Cell Power Systems.

            c.    PLACEMENT SCHEDULE FOR UNIT PLACEMENT. EFC will develop the
                  placement schedule for the RCU 4500 Units being tested by
                  Cooperative Members. This will help to match the current phase
                  of the Testing Program with the best candidates and site
                  locations for Unit placement. Unit placement recommendations
                  will be based primarily on the Fuel Cells Products'
                  specifications and installation and service economics.

            d.    PLACEMENT ISSUES. EFC will collect and evaluate environmental,
                  climatic and other related data that were observed and noted
                  in the Testing Program to develop better criteria for future
                  Fuel Cell Power System installations throughout the United
                  States.

            e.    CUSTOMER INPUT. EFC will secure customer recommendations and
                  input on the program, design issues, improvements or
                  suggestions and include them in the Report sections, as
                  appropriate, to further the design and development of Fuel
                  Cell Power Systems.

            f.    GRID COMPATIBILITY. EFC will evaluate the performance data
                  from the Testing Program to date to identify potential grid
                  interconnection and power quality issues.

            g.    HEAT EXCHANGE. EFC will assist in developing residential heat
                  exchange applications for domestic water and space heating for
                  both the retrofit and new construction applications.

            h.    SHIPPING AND DELIVERY. EFC shall work with H Power to evaluate
                  the information from the Testing Program to determine the most
                  efficient and effective shipping and delivery methods for Fuel
                  Cell Power Systems.

            i.    SERVICING REQUIREMENTS. EFC will evaluate and classify the
                  different skill levels of utility personnel to determine the
                  installation and service abilities of Cooperatives relevant to
                  the Testing Program.

            j.    ASSUMED OBLIGATIONS. EFC shall assume all obligations and
                  liabilities of H Power (including, but not limited to, those
                  set forth in Attachment 3 thereto) with respect to the Fuel
                  Cell Testing Agreements that have been entered into as of the
                  Effective Date between ECO or EFC and ECO's Licensed Members,
                  and H Power shall have no further obligations thereunder. In
                  addition, except with



                                  Page 2 of 10

<PAGE>

                  respect to Grandfathered Distribution Agreements, EFC shall
                  assume all obligations and liabilities of H Power with respect
                  to the Distribution Agreements and H Power shall have no
                  further obligations thereunder.

            2.    FIELD SERVICES SUPPORT TO H POWER.

                  a.    SERVICE AND INSTALLATION SUPPORT FOR FUEL CELL PRODUCTS.
                        EFC will work with H Power to set up the field service
                        and support infrastructure to service H Power's Fuel
                        Cell Products. EFC's support will be in conjunction with
                        the support activities provided by H Power's personnel,
                        and will include such activities as consulting with
                        purchasers about product performance, installation
                        requirements, maintenance and service concerns. H Power
                        will be responsible for all warranties that it may
                        provide from time to time, including its standard
                        warranty provisions for commercial products and for
                        warranty service for test units as stipulated in the
                        Operating Agreement. EFC shall assist H Power in
                        identifying those tasks necessary for setting up a field
                        service infrastructure for H Power and those Fuel Cell
                        activities internal to EFC. Specific tasks to be
                        performed by EFC shall include:

                        i.    Establish a service organization for the
                              installation, maintenance and service of H Power's
                              Fuel Cell Products within the United States. As a
                              part of this proposal, EFC shall conduct a study
                              to identify potential service and quality metrics
                              as based upon customer expectations of the service
                              network;

                        ii.   Assist in the development of budgets detailing the
                              anticipated costs of the potential repair and
                              maintenance of H Power's Fuel Cell Products
                              deployed in the field;

                        iii.  Develop and assist in managing an installation
                              system for all Fuel Cell Products within the
                              United States;

                        iv.   Develop a service data base to assist in
                              statistical analysis that interfaces with H
                              Power's sales and marketing data base to support
                              forward purchasing and the support of spare parts'
                              purchases;

                        v.    Develop the processes required to continually
                              reduce the cost of service and installation;

                        vi.   Obtain and/or assist in obtaining the required
                              permits and licenses for the installation of H
                              Power's Fuel Cell Products in Cooperative
                              Territory; and

                        vii.  Implement an electronic data acquisition and
                              monitoring system, to enable the continuous
                              monitoring of the performance of H Power's Fuel
                              Cell Products deployed in the field.

                  b.    LIMITATIONS. IN NO EVENT SHALL THE PARTIES (INCLUDING
                        THEIR OFFICERS, DIRECTORS, EMPLOYEES, AGENTS AND
                        ATTORNEYS) BE LIABLE FOR ANY INDIRECT, SPECIAL,
                        INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING BUT NOT
                        LIMITED TO LOST PROFITS) IN THE PERFORMANCE OF THEIR
                        DUTIES UNDER THIS AGREEMENT, EVEN IF THEY HAVE NOTICE OF
                        THE POSSIBILTY OF SUCH DAMAGES, EXCEPT FOR (I)



                                  Page 3 of 10

<PAGE>

                        ANY PRODUCT LIABILITY, (II) ANY INFRINGEMENT OF
                        INTELLECTUAL PROPERTY RIGHTS, AND (III) OTHER DAMAGES
                        CAUSED BY NEGLIGENCE OR WILLFUL MISCONDUCT OF THE
                        PARTIES OR THEIR EMPLOYEE(S). HOWEVER, NOTHING HEREIN IS
                        TO LIMIT OR CHANGE THE PROVISIONS OF THE EFC-H POWER
                        OPERATING AGREEMENT (AS AMENDED FROM TIME TO TIME).

                  c.    SERVICE, MAINTENANCE, AND FACILITY REQUIREMENTS. EFC
                        will assist H Power in developing a service and
                        maintenance resource allocation system with a goal to
                        maximize customer service at the lowest reasonable cost.

                  d.    CREATION OF AND SUPPORT FOR H POWER'S SERVICE AND
                        SUPPORT DEPARTMENT. EFC shall propose and arrange for
                        the development and implementation of a new H Power
                        Service and Support Department, and shall have a right
                        of first refusal to manage this Department for H Power
                        under terms to be agreed to by the Parties; provided
                        that EFC's proposal is found satisfactory by H Power.
                        EFC will, in cooperation with H Power:

                        i.    Develop position descriptions, hiring criteria,
                              and a performance evaluation process for service
                              and support employees;

                        ii.   Work with H Power's engineering and other staff to
                              develop servicing and maintenance requirements for
                              Fuel Cell Products compatible with the product
                              design;

                        iii.  Assist H Power in determining H Power's
                              requirements for the hiring of an after market
                              service and support manager; and field service
                              engineers, if appropriate.

                  e.    CREATION OF AND SUPPORT FOR H POWER'S DOMESTIC SERVICE
                        NETWORK. EFC shall assist in the creation of H Power's
                        domestic service network, and shall have the right of
                        first refusal to manage this network, under terms to be
                        agreed to by the Parties, including the following
                        duties:

                        i.    Identify those Cooperative members deemed suitable
                              to be appointed as a field service office to
                              support field service and installation hereinafter
                              (the "Satellite Offices");

                        ii.   Determine the suitable geographical locations
                              within the United States to maintain field service
                              office(s);

                        iii.  Perform a field study to determine the use of HVAC
                              suppliers, renewable energy systems integrators,
                              or mechanical and electrical contractors to
                              support the field service and installation
                              function; and

                        iv.   Assist H Power in maintaining a minimum inventory
                              of spare parts in the Satellite Offices to support
                              field services repairs.

                  f.    TRAINING AND DOCUMENTATION. EFC shall assist H Power in
                        H Power's on-going process of documentation development
                        and training development for H Power's Fuel Cell
                        Products, including:



                                  Page 4 of 10

<PAGE>

                        i.    Develop manuals for Fuel Cell Products with the
                              assistance of H Power engineers, including
                              installation, operation and service and
                              maintenance; and

                        ii.   Assist in the training of field service personnel
                              at H Power's Monroe facility in the installation
                              and operation and repair of H Power's Fuel Cell
                              Products.

                  g.    PROCESS RELATED ISSUES

                        i.    Reporting

                                    EFC shall assist H Power in creating and
                                    implementing a service reporting and
                                    analysis system for all Fuel Cell Products
                                    that includes performance issues, the number
                                    and nature of field service calls, and other
                                    items.

                        ii.   Continual Product Improvement

                                    EFC shall work with ECO's Engineering
                                    Committee and others as appropriate to
                                    establish a system that captures performance
                                    information from Fuel Cell Product users to
                                    assist H Power in achieving its goal of
                                    continued product improvement.

            3.    PROJECT MANAGER. EFC's Project Manager for this Agreement
                  shall be Brian Wierenga. The Project Manager shall, in
                  addition to the other duties prescribed in this Agreement,
                  develop a travel budget for this Agreement, working closely
                  with H Power. During the term of this Agreement, Mr. Wierenga
                  shall integrate the H Power activities described herein into
                  his EFC workload, and shall be responsible for establishing
                  work priorities, schedules, and completion of work requests.
                  Mr. Wierenga shall inform both EFC and H Power when potential
                  or real conflicts of activities or scheduling exist, and the
                  Parties shall mutually resolve such conflicts for Mr.
                  Wierenga. During the term of this Agreement, H Power shall not
                  solicit any EFC staff for employment.

                  H Power and EFC shall agree to prepare travel (including
                  transportation, lodging, meals, and entertainment) and other
                  budgets from time to time to carry out the purposes of this
                  Agreement. In addition to the payments made under Attachment A
                  of this Agreement, any travel to be performed at H Power's
                  request that exceeds $3,000 per month shall be paid for by H
                  Power, except as may otherwise be agreed to in writing by the
                  Parties. EFC shall provide satisfactory documentation for such
                  expenses in such detail as H Power may reasonably request.

            4.    PAYMENT FOR TEST REPORTING, ENGINEERING AND FIELD SERVICES.

                  Subject to Sections 5, 6 and 7 hereof, in exchange for the
                  above services, H Power will pay EFC up to $2.2 million per
                  the Schedule in Attachment A of this Agreement. EFC may bill H
                  Power monthly or quarterly for its services. Payment of
                  invoices will be due and payable 15 days after receipt by H
                  Power.

            5.    AFFIRMATIVE AND NEGATIVE COVENANTS.



                                  Page 5 of 10

<PAGE>

                  Notwithstanding anything contained in this Agreement to the
                  contrary, this Agreement is subject to certain binding
                  Affirmative and Negative Covenants ("Covenants") contained in
                  a "Memorandum of Agreement," entered into by the Parties on
                  the date of this Agreement.

            6.    NO MATERIAL ADVERSE CHANGE. Notwithstanding anything contained
                  in this Agreement to the contrary, H Power shall have no
                  obligation to make payments to EFC during the Term hereof, if
                  there has been a "Material Adverse Change." For the purposes
                  of this Agreement, a Material Adverse Change shall only be
                  defined as a material violation of Sections 2, 3, 4, or 5 of
                  the Memorandum of Agreement.

            7.    FAILURE TO COMPLY. Notwithstanding anything contained in this
                  Agreement to the contrary, upon ECO's and/or EFC's breach of
                  any of the Affirmative or Negative Covenants set forth in the
                  Memorandum of Agreement, H Power shall have the unilateral
                  right to suspend payment of any monies due to EFC hereunder
                  (including those set forth on Attachment A hereto) until such
                  time that ECO and/or EFC cures such breach to H Power's
                  satisfaction.

            8.    TERM.

                  This Agreement shall terminate upon: i) the completion of
                  EFC's and ECO's duties referred to herein; or ii) the written
                  agreement of the Parties.

            9.    DISPUTES.

                  The Parties agree that any and all controversies or claims
                  arising out of or relating to this Agreement, or any alleged
                  breach hereof, shall be resolved by binding arbitration as
                  prescribed herein, upon 30 days' written notice to the other
                  Party. In that event, each Party will select one (1)
                  arbitrator, and those two (2) will select a third. The
                  arbitrators shall conduct the arbitration under the then
                  current rules of the American Arbitration Association ("AAA"),
                  unless otherwise provided herein. The arbitrator(s) will be
                  selected in accordance with AAA procedures from a list of
                  qualified arbitrators maintained by AAA. The arbitration will
                  be conducted in Washington, D.C. and all expedited procedures
                  prescribed under AAA rules will apply. Unless the Parties
                  otherwise agree, the proceedings will be completed within
                  forty-five (45) days of the Parties' receipt of notice of
                  arbitration. Each Party will bear its own costs and attorney's
                  fees and disbursements; and shall share equally the costs of
                  the arbitrators.

            10.   MUTUAL COOPERATION.

                  The Parties agree to take such other actions and execute such
                  other documents as shall be necessary to carry out the
                  provisions of this Agreement.

            11.   INTEGRATION.



                                  Page 6 of 10

<PAGE>

                  With the exception of the Operating Agreement and the
                  Memorandum of Agreement, this Agreement (including any
                  Schedules and Exhibits attached hereto) constitutes the entire
                  agreement among the Parties with respect to the subject matter
                  hereof and supercedes all prior and contemporaneous agreements
                  and undertakings, written or oral, of any nature whatsoever of
                  the Parties hereto with respect to the subject matter hereof.

            12.   NOTICES. All notices, and other communications hereunder shall
                  be in writing and shall be deemed to have been duly given when
                  delivered in person, by telecopy (with confirmation of
                  transmission), by express or overnight mail delivered by a
                  nationally recognized air courier (delivery charges prepaid),
                  or by registered or certified mail (postage prepaid, return
                  receipt requested) to the Parties at their respective
                  addresses set forth in the preamble of this Agreement or to
                  such other address as the Party to whom notice is given may
                  have previously furnished to the other Parties in writing in
                  the manner set forth above. Any notice or communication
                  delivered in person shall be deemed effective on delivery. Any
                  notice or communication sent by telecopy or by air courier
                  shall be deemed effective on the first business day at the
                  place at which such notice or communication is received
                  following the day on which such notice or communication was
                  sent. Any notice or communication sent by registered or
                  certified mail shall be deemed effective on the fifth business
                  day at the place from which such notice or communication was
                  mailed following the day on which such notice or communication
                  was mailed.

            13.   PARTY'S RELATIONSHIP. Neither Party by this Agreement makes
                  the other Party its legal representative or agent. Neither
                  Party shall assign this Agreement to any other third party,
                  without the other Party's prior written permission, except
                  that ECO and ECO Fuel Cells may assign it to a Cooperative
                  Member.

            14.   NO RIGHTS IN THIRD PARTIES. Nothing contained in this
                  Agreement shall be construed as giving rise to any rights to
                  enforce its provisions to any person or entity not a Party to
                  this Agreement under any legal theory.

            15.   COUNTERPARTS. This Agreement may be executed in any number of
                  counterparts, each of which shall be deemed to be an original
                  as against any Party whose signature appears thereon, and all
                  of which shall together constitute one and the same
                  instrument. This Agreement shall become binding when one or
                  more counterparts hereof, individually or taken together,
                  shall bear the signatures of all the Parties hereon as
                  signatories.

            16.   SEVERABILITY. If any provision of this Agreement for any
                  reason shall be held to be illegal, invalid or unenforceable,
                  such illegality shall not affect any other provision of this
                  Agreement, but this Agreement shall be construed as if such
                  illegal, invalid or unenforceable provision had never been
                  included herein.



                                  Page 7 of 10

<PAGE>

IN WITNESS WHEREOF the undersigned Parties hereby execute this Agreement.

         H POWER CORP.                       H POWER ENTERPRISES OF CANADA, INC.

         /s/ William L. Zang                 /s/ H. Frank Gibbard
         -------------------------------     -----------------------------------



                                  Page 8 of 10

<PAGE>


     ECO FUEL CELLS, LLC                  ENERGY CO-OPPORTUNITY INC.

     /s/ William C. Cetti                 /s/ William C. Cetti
     ----------------------------------   ------------------------------------
     William C. Cetti, President & CEO    William C. Cetti, President and CEO



                                  Page 9 of 10

<PAGE>


                                  ATTACHMENT A

        TEST REPORTING, ENGINEERING SERVICES AND FIELD SERVICES AGREEMENT
                                      AMONG
                 ECO FUEL CELLS, LLC, ENERGY CO-OPPORTUNITY INC.
                                       AND
                                  H POWER CORP.

                            H POWER'S PAYMENTS TO EFC



         Subject to the terms and conditions set forth in the Agreement, H Power
         shall make the following payments to EFC:


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------
                                APRIL 2002     QTR 2-2002     QTR 3-2002     QTR 4-2002     SUBTOTAL
=====================================================================================================
<S>                             <C>               <C>            <C>            <C>          <C>
Field Services                      [*]            [*]            [*]            [*]          [*]
-----------------------------------------------------------------------------------------------------
Test Program Evaluation/Report      [*]            [*]            [*]            [*]          [*]
=====================================================================================================
                        TOTAL       [*]            [*]            [*]            [*]          [*]
-----------------------------------------------------------------------------------------------------

<CAPTION>
----------------------------------------------------------------------------------------------------------
                                  QTR 1-2003     QTR 2-2003     QTR 3-2003     QTR 4-2003       TOTALS
==========================================================================================================
<S>                                  <C>            <C>            <C>            <C>            <C>
Field Services                        [*]            [*]            [*]            [*]            [*]
----------------------------------------------------------------------------------------------------------
Test Program Evaluation/Report        [*]            [*]            [*]            [*]            [*]
==========================================================================================================
                        TOTAL         [*]            [*]            [*]            [*]         $2,200,000
----------------------------------------------------------------------------------------------------------
</TABLE>


---
* Confidential

                                  Page 10 of 10