Exhibit 10.36.5

AGREEMENT TO PURCHASE CONTRACT PAYMENTS

THIS AGREEMENT TO PURCHASE CONTRACT PAYMENTS (this "Agreement'), dated as of May
5 2006 is executed and delivered by NORTHEAST UTILITIES, a Massachusetts
business trust (the "Guarantor"), AMERESCO, INC., a Delaware corporation
("Ameresco"), and General Electric Capital Corporation, a Delaware corporation
("GECC"). Capitalized terms used in this Agreement shall have the same meaning
assigned to them in the Guaranty (defined below) unless otherwise indicated. The
Guarantor, Ameresco and GECC shall each be referred to as a "Party" and
collectively as the "Parties".

RECITALS

WHEREAS, in accordance with the federal energy savings performance contracts
(each, an "ESPC"), identified on Schedule 1 attached hereto, the United States
of America through various agencies and departments (each, an "Ordering
Agency"), issued to Select Energy Services, Inc. (the "Seller") certain task
orders (as amended, modified, supplemented, renewed or extended from time to
time in accordance therewith, together with all exhibits, schedules, annexes and
other attachments thereto, collectively, the "Task Orders") identified on
Schedule 1, which provide for, among other things, the Seller to implement
energy conservation projects ("ECM Projects") at each Ordering Agency's site;

WHEREAS, each Ordering Agency is required under the relevant Task Order to make
periodic installment payments in the amounts and on the dates set forth therein
(collectively, together with interest owed by the relevant Ordering Agency under
the Prompt Payment Act, as. amended, 31 U.S.C. §§ 3901-3907, and payments owed
by the relevant Ordering Agency upon termination, buydown or buyout of the Task
Order, the "Contract Payments");

WHEREAS, in conjunction with that certain Master Purchase Agreement (as amended,
modified, supplemented, renewed or extended from time to time in accordance
therewith, together with all exhibits, schedules, annexes and other attachments
thereto), between Hannie Mae LLC (together with its successors and assigns, the
"Buyer') and the Seller, the Seller executed and delivered certain assignment
schedules pursuant to the Master Purchase Agreement assigning the Contract
Payments to the Buyer (each such schedule, as amended, modified, supplemented,
renewed or extended from time to time in accordance therewith, together with all
exhibits, schedules, annexes and other attachments thereto, shall be referred to
as an "Assignment Schedule ") attached hereto as Schedule 2, which sold,
assigned, transferred and conveyed to the Buyer all of the Seller's right, title
and interest in and to the Contract Payments;

WHEREAS, in support of each Assignment Schedule, the Guarantor executed a
Guaranty in favor of the Buyer (each a "Guaranty") whereby the Guarantor agreed
to guarantee the obligations of the Seller;

WHEREAS, each Guaranty provides that, should Guarantor elect not to renew or
extend the Guaranty, the Buyer may require the Guarantor to purchase the
remaining Contract Payments from the Buyer;

WHEREAS, Ameresco and NU Enterprises, Inc., a Connecticut corporation and wholly
owned subsidiary of Guarantor, executed a Stock Purchase Agreement, dated
February 3, 2006, whereby Ameresco agreed to purchase the capital stock of the
Seller. Under the terms of the Stock Purchase Agreement, the financing of the
Contract Payments must be refinanced so as to release the Guarantor from each
Guaranty; and

WHEREAS, if Guarantor is required to purchase the Contract Payments from Buyer,
the Guarantor desires to sell such Contract Payments to the Seller, GECC desires
to purchase the Contract Payments from the Seller, and Ameresco desires to cause
Seller to purchase from the Guarantor and to sell to GECC the Contract Payments.

NOW, THEREFORE, for other good and valuable consideration, the receipt and
adequacy of which are hereby acknowledged, the Parties agree as follows:

1.

Purchase of Contract Payments.  Subject to the terms hereof, GECC agrees to
purchase the Contract Payments from the Seller. The purchase price for the
remaining Contract Payments shall be determined as set forth in Section 2 below.
GECC shall be obligated to purchase the applicable Contract Payments related to
each Task Order on the dates set forth on Schedule 3 hereto (each a "Purchase
Date").  The purchase shall be effected by wire transfer to an account to be
provided by Seller prior to the Purchase Date. The contract documents effecting
the transfer of the Contract Payments to GECC shall be in the form of the Master
Purchase Agreement between the Seller and GECC dated on or about May , 2006 (the
"MPA "). The Guarantor, Ameresco, the Seller and GECC shall work together in
good faith to execute all other reasonable agreements necessary to effect the
transfer of the Contract Payments (i.e., governmental consents,
indemnifications, opinions of counsel, etc.).

2.

Purchase Price.  GECC agrees, as consideration for such purchase, to pay to the
Seller an amount equal to the net present value of the Contract Payments
discounted to the applicable Payment Date at an interest rate equal to the sum
of 56 basis points (0.56%) plus the average life swap rate index (collectively,
the "Discount Rate"), (as referenced in the Bloomberg Index) as of the close of
business two (2) days prior to the Purchase Date (the "Purchase Price").

3.

Conditions to Purchase.  GECC's obligation to purchase the Contract Payments is
subject to the satisfactory fulfillment of the following conditions and final
approval of its investment committee:

(a)

The Seller shall not become insolvent, make an assignment for the benefit of its
creditors or be subject to relief granted by the United States Bankruptcy Court
or. commit or permit to occur or continue any act, condition or proceeding which
constitutes an act of bankruptcy under any applicable federal or state law or
have a material adverse

change in its financial or operating condition as determined by GECC in its
reasonable discretion;

(b)

Seller shall not be in default of its obligations under any Task Order;

(c)

Receipt by GECC of each ESPC and Task Order and all other documents related to
each Task Order, in form and substance satisfactory to GECC;

(d)

Completion of due diligence by GECC regarding the ESPCs and Task Orders,
including, but not limited to:

i)

Evidence that the Contract Payments are being made promptly;

ii)

Evidence or representations and warranties that the Task Orders are valid,
binding and enforceable against the Seller and the relevant Ordering Agency;

iii)

The performance of the ECM Projects is equal to or better than projected;

iv)

The Contract Payments under each Task Order are sufficient to cover GECC's
investment (otherwise GECC must receive sufficient indemnification for any
shortfall);

v)

None of the locations where the ECM's are installed is on the BRAC list; and

vi)

Maintenance and verification of the ECM Projects is being performed and is
meeting or exceeding expectations; and

(e)

Receipt by GECC of all other documents required to be delivered to f GECC
pursuant to the MPA, between the Seller and GECC, in form and substance
satisfactory to GECC.

The Federal Finance unit of GECC agrees to submit and pursue final approval of
its investment committee to purchase the applicable Contract Payments as set
forth herein, so long as what has been represented to GECC by the Guarantor and
Ameresco with respect to the ESPCs and Task Orders is satisfactorily confirmed
by GECC as a result of its due diligence

4.

Representations.

(a)

The Guarantor represents and warrants that (a) the Guarantor is a Massachusetts
business trust duly organized, validly existing and in good standing under the
laws of its jurisdiction of organization and has the power to enter into and
perform its obligations under this Agreement, and (b) this Agreement has been
duly authorized by the Guarantor, has been duly executed and delivered by the
Guarantor and constitutes the legal, valid and binding obligation of the
Guarantor enforceable against the Guarantor in accordance with its terms, except
as such enforceability may be subject to the effect of general principles of
equity or limited by or subject to any bankruptcy, insolvency,

reorganization, moratorium, or other similar laws affecting the enforcement of
creditors' rights generally.

(b)

Ameresco represents and warrants that (a) Ameresco is a corporation duly
organized, validly existing and in good standing under the laws of its
jurisdiction of organization and has the power to enter into and perform its
obligations under this Agreement, and (b) this Agreement has been duly
authorized by , has been duly executed and delivered by the Ameresco and
constitutes the legal, valid and binding obligation of the Ameresco enforceable
against Ameresco in accordance with its terms, except as such enforceability may
be subject to the effect of general principles of equity or limited by or
subject to any bankruptcy, insolvency, reorganization, moratorium, or other
similar laws affecting the enforcement of creditors' rights generally.

(c)

The Seller represents and warrants that (a) the Seller is a corporation duly
organized, validly existing and in good standing under the laws of its
jurisdiction of organization and has the power to enter into and perform its
obligations under this Agreement, and (b) this Agreement has been duly
authorized by the Seller, has been duly executed and delivered by the Seller and
constitutes the legal, valid and binding obligation of the Seller enforceable
against the Seller in accordance with its terms, except as such enforceability
may be subject to the effect of general principles of equity or limited by or
subject to any bankruptcy, insolvency, reorganization, moratorium, or other
similar laws affecting the enforcement of creditors' rights generally.

(d)

GECC represents and warrants that (a) GECC is a corporation duly organized,
validly existing and in good standing under the laws of its jurisdiction of
organization and has the power to enter into and perform its obligations under
this Agreement, and (b) this Agreement has been duly authorized by GECC, has
been duly executed and delivered by GECC and constitutes the legal, valid and
binding obligation of GECC enforceable against GECC in accordance with its
terms, except as such enforceability may be subject to the effect of general
principles of equity or limited by or subject to any bankruptcy, insolvency,
reorganization, moratorium, or other similar laws affecting the enforcement of
creditors' rights generally.

5.

No Waivers,.

No failure or delay by any Party to this Agreement in exercising any right,
power or privilege under this Agreement shall operate as a waiver thereof nor
shall any single or partial exercise thereof preclude any other or further
exercise thereof or the exercise of any other right, power or privilege. The
rights and remedies herein provided are cumulative and not exclusive of any
rights or remedies provided by law or in any other document, instrument or
agreement executed in connection with this Agreement.

6.

Severability.

 If any provision of this Agreement is held to be illegal, invalid or
unenforceable under present or future laws effective during the term thereof,
such provision shall be fully severable, this Agreement shall be construed and
enforced as if such illegal, invalid of unenforceable provision had never
comprised a part thereof, and the remaining provisions thereof

shall remain in full force and effect and shall not be affected by the illegal,
invalid or unenforceable provision or by its severance therefrom.

7.

Modification in Writing.

No modification, consent, amendment, or waiver of any provision of this
Agreement, and no consent to any departure by the Parties therefrom, shall be
effective unless the same shall be in writing and signed by an officer of the
Buyer, and then shall be effective only in the specific instance and for the
specific purpose for which given.

8.

Successors and Assigns.

All covenants and agreements contained in this Agreement shall be binding on the
Parties and their successor and assigns and. shall inure to the benefit of the
Buyer and its successors and assigns. Neither Party shall have the right to
assign this Agreement without the express written consent of the other Party.

9.

Governing Law.

The laws of the State of New York applicable to contracts shall govern the
validity, interpretation, and performance of this Agreement. Any action to
enforce or interpret this Agreement shall be commenced or maintained only in,
and each party consents to the jurisdiction of, a New York court of competent
jurisdiction in New York, New York or a federal court of competent jurisdiction
in New York, New York, and each party waives any venue, convenient forum,
removal, jurisdiction or other rights to the contrary.

10.

Expenses.

Each Party agrees to pay, and save the other Party harmless against liability
for the payment of all, all fees and expenses of the other Party, including,
without limitation, attorneys' fees and disbursements, incurred in connection
with enforcing any rights under this Agreement, including, without limitation,
costs and expenses incurred in any bankruptcy case.

11.

Notices.

All notices, requests, demands and other communications to either Party shall be
in writing 'and shall be given to such Party at its address or telecopier number
set forth below or such other address or telecopier number as such Party may
hereafter specify. Each such notice, request or other communication shall be
effective (a) if given by registered or certified mail, postage prepaid, return
receipt requested, as of the date of delivery shown on the return receipt, or
(b) if given by any other means, including by hand, overnight courier or
facsimile transmission, when delivered to the address or telecopier number
specified below.

If to the Guarantor:

 

Northeast Utilities

 

107 Selden Street

 

Berlin, CT 06070

 

Telecopier: (860) 665-2807

 

Attn: John J. Roman

If to Ameresco:

 

Ameresco, Inc.

 

111 Speen Street, Suite 410

 

Framingham, MA 01701

 

Telecopier: (508) 661-2200

 

Attn: General Counsel

If to the Seller:

 

Select Energy Services, Inc.

 

111 Speen Street, Suite 410

 

Framingham, MA 01701

 

Telecopier: (508) 661-2200

 

Attn: General Counsel

If to GECC

 

General Electric Capital Corporation

 

2000 Corporate Ridge, Suite 1095

 

McLean, VA 22102

 

Telecopier: (703) 749-3527

 

Attn: Federal Finance Risk and Operations Manager

12.

Complete Agreement.

This Agreement constitutes the entire agreement between the Parties and
supersedes and nullifies all prior negotiations, proposals or stipulations.
There are no prior or contemporaneous agreements or presentations not included
or provided for herein. No agent or representative of either party has authority
to make, nor is either party relying upon, any representation not expressly
contained herein.

13.

No Trustee Liability.

  No Trustee or shareholder of Guarantor shall be held to any liability
whatsoever for any obligation under this Agreement, and such Agreement shall not
be enforceable against any such Trustee in their or his or her individual
capacities or capacity. This Agreement shall be enforceable against the Trustees
of Guarantor only as such, and every person, firm, association, trust or
corporation having any claim or demand arising under this Agreement and relating
to Guarantor, its shareholders or Trustee shall look solely to the trust estate
of Guarantor for the payment or satisfaction thereof.

[Remainder of Page Intentionally Left Blank]

IN WITNESS WHEREOF,-the undersigned have executed this Agreement as of the date
first above written.

GENERAL ELECTRIC CAPITAL CORPORATION

AMERESCO, INC.

  

By:

/s/ Robert Whartenby

By:

/s/ Andrew B. Spence

           Name:  Robert Whartenly

           Name:  Andrew B. Spence

           Title: Risk & Operations Manager

           Title: VP/CFO

NORTHEAST UTILITIES

By:

/s/ David R. McHale

Name:

 David R. McHale

Title:

 Senior VP & CFO