STANDBY PAYMENT AGREEMENT


              AGREEMENT dated as of June 11, 2001 (this "Agreement") by and
among U.S. Energy Systems, Inc., a Delaware corporation ("USE"), USE Canada
Acquisition Corp. ("USE Canada," and together with USE, the "USE Parties"), and
AJG Financial Services, Inc., a Delaware corporation ("AJG").


                              W I T N E S S E T H:

              WHEREAS, USE Canada and Trigen-Canada Company LLC ("Trigen") are
party to that certain stock purchase agreement (the "Stock Purchase Agreement")
dated as of June [ ], 2001 providing for the purchase by USE Canada of all of
the issued and outstanding shares of Trigen Energy Canada Company ("USE OpCo")
as contemplated therein;

              WHEREAS, USE owns 100% of the issued and outstanding shares of USE
Canada Holdings Corp. ("USE Holdco") which in turn owns 100% of the issued and
outstanding shares of USE Canada which in turn shall own 100% of the issued and
outstanding shares of USE OpCo after consummation of the transactions
contemplated by the Stock Purchase Agreement.

              WHEREAS, USE Canada will pay a portion of the purchase price under
the Stock Purchase Agreement by USE Canada's issuing a short-term note (the
"Note") in the initial principal amount of Twenty-Four Million Canadian Dollars
C. $24,000,000 subject to subsequent adjustment pursuant to Section 2.3 of the
Stock Purchase Agreement;

              WHEREAS, the Stock Purchase Agreement contemplates that the USE
Parties shall deliver to Trigen, at the Closing of the transactions contemplated
by the Stock Purchase Agreement (the "Closing") a guarantee of USE Canada's
obligations under the Note by AJG (the "Stock Purchase Agreement Condition");

              WHEREAS, the Closing is occurring simultaneous with the execution
of this Agreement;

              WHEREAS, the USE Parties are delivering to Trigen a guarantee (the
"Guarantee") of AJG substantially in the form of Exhibit A hereto to satisfy the
Stock Purchase Agreement Condition;

              WHEREAS, pursuant to  the Guarantee, AJG  is guaranteeing  USE
 Canada's obligations pursuant to the Note;

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              WHEREAS, it is a condition to AJG's delivering the Guarantee, that
the USE Parties enter into this Agreement.

              NOW, THEREFORE, in consideration of the benefits accruing to the
parties, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto hereby make the following representations and warranties and
hereby covenant and agree as follows:

              1. As used in this Agreement, capitalized terms not defined herein
which are defined in the Stock Purchase Agreement are used herein as therein
defined.

              2.    AJG's fee for causing the issuance of the Guarantee is
$ 150,000, of which $50,000 was paid previously by USE. USE shall pay the
balance of $ 100,000 upon AJG's issuance of the Guarantee .


                  3. (a) USE agrees to diligently pursue the procurement and
              closing of financing on commercially reasonable terms to pay off
              the Note on or before the due date of the Note (the "Due Date").
              In the event such financing will not be closed on or before the
              Due Date, USE agrees to give AJG ten business days' notice that
              AJG will become liable to perform under the Guarantee and fund the
              Note. Upon the receipt of USE's notice, AJG agrees to lend Ten
              Million Dollars ($10,000,00) to USE Canada (the "Loan") for the
              payment of the Note, such funds to be received at least five
              business days prior to the Due Date in immediately available
              funds. USE Canada agrees to pay all amounts due under the Note,
              including principal and accrued interest to Trigen on the Due Date
              using such funds provided by AJG under this Section 3(a) together
              with such other funds required to pay all amounts due under the
              Note, and to procure a satisfaction and release of AJG from Trigen
              under the Guarantee.

              (b) The Loan will have an interest rate of 9% per annum. On the
              Payment Date (defined below) USE Canada shall pay the interest
              which accrued under this Section 3(b) during the prior calendar
              year.

              (c) USE Canada will be required to make annual principal payments
              on the Loan equal to the "net after-tax cash flow" (as defined
              below) during the prior calendar year from the projects being
              operated by USE OpCo (the "Projects"), less the sum of (i)
              interest payments pursuant to Section 3(b) paid simultaneously
              with such principal payment and (ii) the Additional Fee (as
              defined below) paid to AJG simultaneously with such principal
              payment and (iii) principal and interest payments due on any third

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              party debt. Net after-tax cash flow means the net revenues from
              the Projects less royalties and all reasonable, necessary and
              normal expenses of the Projects, including, without limitation,
              operation, fuel, maintenance, repairs, capital expenditures,
              parts, labor and general overhead, reserves, services,
              professional fees and disbursements, income and property taxes,
              severance expenses and insurance such that the net after-tax cash
              flow will consist of the net cash flow from the Projects after
              taxes (including income taxes) but before debt service and
              distributions to equity investors.

              (d) USE Canada shall have the right, but not the obligation, to
              make or cause to be made additional principal payments without
              premium at any time until the Loan has been paid off in its
              entirety.

              (e) USE will pay AJG an additional fee (the "Additional Fee") each
              year equal to (i) the average outstanding balance on the Loan for
              the prior calendar year, divided by the sum of the outstanding
              balance on the Loan at the end of such calendar year and USE's
              total cumulative direct or indirect investment in USE Holdco, USE
              Canada and/or USE OpCo at the end of such calendar year,
              multiplied by (ii) the "net after-tax cash flow" (as defined
              above) from the Projects for such calendar year, (iii) less the
              sum of (A) the interest payment accrued by AJG or any assignee of
              AJG pursuant to Section 3(b) during such calendar year and (B) any
              principal and interest payments made on any third party debt
              during such calendar year. The interest payments made under such
              Section 3(b) hereof, the annual principal payments and Additional
              Fee are payable by USE on an annual basis within 3 months after
              audited financial statements are available for the Projects for
              the calendar year in question (the "Payment Date"). The annual
              principal payments and the Additional Fee are payable, at USE's
              option in cash or in shares of USE's common stock ("USE Stock")
              registered for resale under a registration statement on Form S-3;
              if the Additional Fee is paid by the delivery of shares of USE
              Stock, such shares shall be valued at a price equal to the average
              closing price for USE Stock on the primary exchange on which
              shares of USE Stock are traded for the 20 trading day period
              ending two business days prior to the payment of such Additional
              Fee.

              (f) Once the Loan has been paid off in its entirety, AJG will
              receive an annual residual fee from USE (the "Residual Fee") equaL
              to (i) 1.5% of the net after-tax cash flow from the Projects for
              each such calendar year (or fraction thereof) plus (ii) 1.5% of
              the net after-tax cash flow from the Projects for each such
              calendar year (or fraction thereof) multiplied by the number of
              years (which number shall, if it is not a whole number, be rounded
              up to the next whole number) that the Loan remained outstanding;
              provided, however, that in no event shall the Residual Fee exceed
              10% of the net after-tax cash flow from the Projects for any such
              calendar year or fraction thereof. The Residual Fee will be paid
              by USE on an annual basis within 3 months after audited financial

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              statements are available for the Projects. The Residual Fee is
              payable in cash or, if acceptable to all of the parties hereto,
              50% in cash and 50% in shares of USE Stock registered for resale
              under a registration statement on Form S-3; if the Residual Fee is
              paid by the delivery of shares of USE Stock, such shares shall be
              valued at a price equal to the average closing price for USE Stock
              on the primary exchange on which shares of USE Stock are traded
              for the 20 trading day period ending two business days prior to
              the payment of such Residual Fee.

              (g) Any payments required hereunder shall be subject to any
                  withholding required under applicable Canadian laws.

                  4.      AJG represents and warrants to the USE Parties as
                          follows:

                  (a) AJG is a corporation duly organized, validity existing and
in good standing under the laws of the State of Delaware, and has all requisite
corporate power to own, operate and lease its properties and carry on its
business as the same is now being conducted.

                  (b) AJG has all requisite corporate power and authority to
execute, deliver and perform its obligations under this Agreement, the
Guarantee, and each agreement, document or instrument contemplated hereby or
thereby to which it is a party. The execution, delivery and performance by such
party of this Agreement, the Guarantee, and each such agreement, document or
instrument to which it is a party, and the consummation of the transactions
contemplated hereby and thereby, have been authorized by all necessary action
and (i) do not require the consent, waiver, approval, license or authorization
of any person, entity, or public authority, (ii) do not violate, with or without
the giving of notice and/or the passage of time, any provision of law, and (iii)
will not conflict with or result in a breach or termination of any provision of,
or constitute a default or give rise to a right of termination or acceleration
under, any operating agreement, mortgage, deed of trust, indenture or other
agreement or instrument, or any order, judgment, decree, statute, regulation or
any other restriction of any kind or character, to which such party is a party
or by which any of its assets or properties may be bound, or result in the
creation of any lien, charge or encumbrance upon any of the assets of such
party.

                  (c) This Agreement and the Guarantee have been duly executed
and delivered by such party and constitute, and each other agreement, document,
certificate or instrument contemplated by this Agreement to which it is a party
or the Guarantee when executed and delivered shall constitute, a legal, valid
and binding obligation of such party enforceable against it in accordance with
its terms, except as enforcement may be limited by applicable bankruptcy,
insolvency, reorganization and moratorium laws or by equitable principles
relating to or limiting creditors' rights generally.

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                  The foregoing representations and warranties shall survive the
Closing for a period two (2) years.

                  5.       Each of the USE Parties hereby represents and
warrants to AJG as follows:

                  (a) USE is a corporation duly organized, validly existing and
in good standing under the laws of the State of Delaware, and has all requisite
corporate power to own, operate and lease its properties and carry on its
business as the same is now being conducted. USE Canada is a corporation duly
organized, validly existing and in good standing under the laws of Canada, and
has all requisite corporate power to own, operate and lease its properties and
carry on its business as the same is now being conducted.

                  (b) Each USE Party has all requisite corporate power and
authority to execute, deliver and perform its obligations under this Agreement,
and each agreement, document or instrument required to be delivered hereby to
which it is a party. The execution, delivery and performance by such party of
this Agreement and each such agreement, document or instrument to which it is a
party, and the consummation of the transactions contemplated hereby and thereby,
have been authorized by all necessary action and (i) do not require the consent,
waiver, approval, license or authorization of any person, entity, or public
authority, (ii) do not violate, with or without the giving of notice and/or the
passage of time, any provision of law, and (iii) will not conflict with or
result in a breach or termination of any provision of, or constitute a default
or give rise to a right of termination or acceleration under, any operating
agreement, mortgage, deed of trust, indenture or other agreement or instrument
or any order, judgment, decree, statute, regulation or any other restriction of
any kind or character, to which such party is a party or by which any of their
assets or properties may be bound, or result in the creation of any lien, charge
or encumbrance upon any of the properties or assets of such party.

                  (c) This Agreement has been duly executed and delivered by
such party and constitutes, and each other document contemplated by this
Agreement to which it is a party when executed and delivered in accordance with
the provisions hereof shall constitute, a legal, valid and binding obligation of
such party enforceable against it in accordance with its terms, except as
enforcement may be limited by applicable bankruptcy, insolvency, reorganization
and moratorium laws or by equitable principles relating to or limiting
creditors' rights generally.

                  The foregoing representations and warranties shall survive the
Closing for a period of two (2) years.

                  6. (a) AJG agrees to indemnify and hold the USE Parties, and
their respective officers, members, managers, agents, employees, attorneys, and
their respective successors and assigns harmless from, and will reimburse them
for, any and all claims, liabilities, losses, damages and expenses (including
without limitation reasonable attorneys fees) incurred by any one or more of

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them after the Closing Date to the extent that they arise from or relate to the
untruthfulness in any material respect of any representation or warranty, or the
breach of any covenant, made by either AJG in this Agreement or the Guarantee.

                  (b) Each USE Party agrees jointly and severally to indemnify
and hold AJG, and its officers, directors, shareholders, agents, employees,
attorneys, and their respective successors and assigns harmless from, and to
reimburse them for, any and all claims, liabilities, losses, damages and
expenses (including without limitation reasonable attorneys fees) incurred by
any one or more of them after the Closing Date to the extent they arise from or
relate to the untruthfulness in any material respect of any representation or
warranty, or the breach of any covenant, made by either USE Party in this
Agreement.

                  (c) Neither Indemnifying Party nor the Indemnified Party may
settle or compromise any claim for which indemnification has been sought and is
available hereunder, over the reasonable objection of the other; provided,
however, that consent to settlement or compromise shall not be unreasonably
withheld or delayed. If, however, the Indemnified Party refuses to consent to a
bona fide offer of settlement which the Indemnifying Party wishes to accept, the
Indemnified Party may continue to pursue such matter, free of any participation
by the Indemnifying Party, at the sole expense of the Indemnified Party. In such
event, the obligation of the Indemnifying Party to the Indemnified Party shall
be equal to the lesser of (i) the amount of the offer of settlement which the
Indemnified Party refused to accept plus the costs and expenses of the
Indemnified Party prior to the date the Indemnifying Party notified the
Indemnified Party of the offer of settlement, and (ii) the actual out-of-pocket
amount the Indemnified Party is obligated to pay as a result of the Indemnified
Party's continuing to pursue such matter.

                  7. If, at any time after the date hereof, any party shall
consider or be advised that any further assignments, conveyances, certificates,
filings, instruments or documents or any other things are necessary or desirable
to consummate any of the transactions contemplated by this Agreement, the other
parties shall, upon request, promptly execute and deliver all such proper
instruments and do all things reasonably necessary and proper to otherwise carry
out the purposes of this Agreement.

                  8. (a) This Agreement may be amended, modified or supplemented
only by a written instrument executed by the parties hereto. The provisions of
this Agreement may be waived only by an instrument in writing executed by the
party granting the waiver. The waiver by any party hereto of a breach of any
provision of this Agreement shall not operate or be construed as a further or
continuing waiver of such breach or as a waiver of any other or subsequent
breach.

                  (b) No failure on the part of any party to exercise, and no
delay in exercising, any right, power or remedy hereunder shall operated as a

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waiver thereof, nor shall any single or partial exercise of such right, power or
remedy by such party preclude any other or further exercise thereof or the
exercise of any other right, power or remedy. All remedies hereunder are
cumulative and are not exclusive of any other remedies provided by law.

                  9.     Each party shall  each be responsible  for all  of its
respective fees and expenses incurred in connection with this transaction.

                  10. This Agreement shall inure to the benefit of and be
binding upon the parties hereto, and their successors and permitted assigns.
Nothing in this Agreement, express or implied, is intended to confer on any
person other than the parties hereto, and their respective successors and
permitted assigns any rights, remedies, obligations or liabilities under or by
reason of this Agreement.

                  11. This Agreement shall not be assignable by the parties
without the prior written consent of the other parties, except that after the
Closing, subject to compliance with all applicable securities laws, each party
may assign its respective rights and delegate its respective obligations under
this Agreement to any third party which assumes all of the assigning party's
obligations hereunder provided, however, that such assigning party shall remain
liable for all of its obligations hereunder.

              12. This Agreement may be executed in multiple counterparts, each
of which signed acknowledgement of receipt required shall be deemed to be an
original, and all such counterparts shall constitute but one instrument.

              13. All notices, requests, demands and other communications which
are required or may be given under this Agreement shall be in writing and shall
be deemed to have been duly given or made: if by hand, immediately upon
delivery; if by telex, telecopier, or similar electronic device, immediately
upon sending, provided it is sent on a business day, but if not, then
immediately upon the beginning of the first business day after being sent; if by
Federal Express, Express Mail or any other overnight delivery service, on the
first business day after dispatch, signed acknowledgment of receipt required.
All notices, requests and demands are to be given or made to the parties at the
following addresses (or to such other address as either party may designate by
notice in accordance with the provisions of this paragraph):

If to either USE Party:

                           U.S. Energy Systems, Inc.
                           One North Lexington Avenue, 4th Floor
                          White Plains, New York 10601
                           Facsimile No.: 914-993-5190
                           Attention: President and Chief Operating Officer

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with a copy to:

                           U.S. Energy Systems, Inc.
                           One North Lexington Avenue, 4th Floor
                          White Plains, New York 10601
                           Facsimile No.: 914-993-5190
                           Attention: General Counsel


If to AJG:                 AJG Financial Services, Inc.
                           Two Pierce Place
                             Itasca, Illinois 60143
                           Facsimile No.: 630-285-4272
                           Attention:  Mark Strauch, Executive Vice President


with a copy to:
                          AJG Financial Services, Inc.
                           Two Pierce Place
                             Itasca, Illinois 60143
                             Facsimile No.: 630-285-
                           Attention:  Kerry Abbott, Assistant General Counsel

                    14. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York applied to contracts to be
performed wholly within the State of New York, without giving effect to the
principles of conflicts of law. Any judicial proceeding brought by or against
any party hereto with respect to this Agreement or any related agreement may be
brought in the Supreme Court of the State of New York located in the County of
New York or in the United States District Court for the Southern District of New
York and, by execution and delivery of this Agreement, each party accepts, for
itself or himself and in connection with its or his properties, generally and
unconditionally, the non-exclusive jurisdiction of the aforesaid courts, and
irrevocably agrees to be bound by any judgment rendered thereby in connection
with this Agreement. Each party hereto hereby waives personal service of any and
all process upon it or him and consents that all such service of process may be
made by registered mail (return receipt requested) directed to such party at the
address set forth pursuant to Section 13 hereto and service so made shall be
deemed completed five (5) days after the same shall have been so deposited in
the mails of the United States of America. Nothing herein shall affect the right
to serve process in any manner permitted by law or shall limit the right of any
party to bring proceedings against any other party in the courts of any other
jurisdiction. The parties hereto waive any objection to jurisdiction and venue
of any action instituted hereunder in any court referred to above and shall not
assert any defense based on lack of jurisdiction or venue or based upon forum
non conveniens.

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                    15. If any part of this Agreement is contrary to, prohibited
by, or deemed invalid under applicable laws or regulations, such provision shall
be inapplicable and deemed omitted to the extent so contrary, prohibited or
invalid, but the remainder hereof shall not be invalidated thereby and shall be
given effect so far as possible.

                    16.    This Agreement shall not become effective until the
Closing.

                    17. This Agreement and the exhibits hereto set forth the
entire agreement and understanding between the parties hereto with respect to
the subject matter hereof and supersede any prior negotiations, agreements,
letters of intent, understandings or arrangements between the parties hereto
with respect to the subject matter hereof.

                    18.    (a)      Unless some meaning and intent  is apparent
from the context of the Agreement, the plurals shall include the  singular and
vice versa, and masculine, feminine and neuter words shall be used
interchangeably.


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                    (b)    All references  to dollars  shall be deemed  to  be
references  to  U.S. dollars, unless another type of  dollars is  specifically
identified, and all payments  hereunder shall be made in U.S. dollars (or shares
of USE Stock).

              IN WITNESS WHEREOF, the parties hereto have executed and delivered
this Agreement as of the day and year first above written.


                                  U.S. ENERGY SYSTEMS, INC.

                                 By:  /s/Goran Mornhed
                                     ----------------------------------------
                                  Name:  Goran Mornhed
                                  Title: President and Chief Operating Officer

                                  USE CANADA ACQUISITION CORP.

                                  By: /s/Goran Mornhed
                                      ----------------------------------------
                                  Name:  Goran Mornhed
                                  Title: President and Chief Operating Officer

                                  AJG FINANCIAL SERVICES, INC.

                                  By: /s/Mark Strauch
                                       ---------------------------
                                  Name:  Mark Strauch
                                  Title: Executive Vice President

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