<PAGE>
                                                                   EXHIBIT 10.11
ABN - AMRO BANK

Framework Agreement for the Granting of Banking Transactions to Abengoa
-----------------------------------------------------------------------

Abengoa, S.A.
Avenida de la Buhaira, n(0)2
41018 Seville                                              Madrid, July 17, 2002

Dear Sirs

We are pleased to inform you that we have approved a Framework Agreement for the
granting of banking transactions to Abengoa S.A (hereinafter "the Company") and
the subsidiaries to be mentioned later (hereinafter "the Borrowers"), on the
terms laid down herein. This Framework Agreement is discretional in character,
so the transactions deriving therefrom will be established under the terms
agreed between the parties for each individual transaction; there is no
obligation or commitment for the parties to initiate any transaction.

LIMIT. 50 million euros or the equivalent thereof in other currencies, as
specified later. All balances taken up by each and every Borrower under each
transaction will be added together for the calculation of this sum, plus the
available balances of such credit or loan policies as may have been signed at
each moment.

VALIDITY: The Framework Agreement will remain in force until such time as either
party informs the other of its intention to cancel it, without detriment to the
validity of the contracts deriving therefrom and their guarantees.

USE, AVAILABILITY AND SUBJECTION TO THE LAW: the transactions can be made
available to the Company and/or the Borrowers by our branch and/or other
branches or subsidiaries of the bank (hereinafter jointly termed as "Lending
Branches" or, individually, "Lending Branch"). The term "sub-transaction" will
be understood to be each banking transaction made available to each individual
Borrower. The nature, terms and conditions of each type of sub-transaction that
each Lending Branch makes available to a specific Borrower shall be mutually
agreed between the Borrower and the Lending Branch in question. This condition
shall apply in all the following cases: current account credits, letters of
credit, stand-by letters of credit or any other type of guarantee or bonds,
discount operations, foreign currency exchange rate contracts, coverage
transactions or any other transactions that ABN AMRO Bank N.V. or its
subsidiaries might make available to its clients. This document entails no
commitment on our part or on the part of any of our Lending Branches to furnish
you with any sub-transaction. The furnishing of any sub-transaction by any
Lending Branch will be subject to the local availability of funds (both in local
currency and foreign currency) and also the laws, regulations and applicable
policies determined by each Lending Branch in each particular case. Furthermore,
each sub-transaction will be subject to the applicable exchange control
restrictions; it is the responsibility of the Borrower in question to obtain
such permits and/or licenses as may be necessary for these affairs.

1.   ESTABLISHMENT OF A SUB-TRANSACTION: Annex A details the initial Borrowers
     and the sub-transaction limits. Application must always be made in writing
     for the inclusion of any additional sub-transactions or any modifications
     to existing ones. Upon

<PAGE>

     receipt of the application, the Bank will confirm its acceptance in
     writing, after having obtained the corresponding approval from the Risk
     Committees of ABN AMRO, where applicable.

2.   PRICE. The price of each sub-transaction will be established by mutual
     agreement between the Borrower in question and the Lending Branch. In reply
     to your written application at the moment of designating a Borrower, the
     price structure agreed between the Borrower in question and the Lending
     Branch will be sent on to you for your approval before the sub-transaction
     goes ahead.

3.   EXCHANGE RATE FLUCTUATIONS:  The Framework Agreement and each individual
     sub-transaction can be used in one or more convertible  currencies.  If,
     due to the fluctuation of exchange rates, the sum of the debts of the
     Borrowers with the Lending  Branches exceeds the maximum limit  specified
     above  (calculated by us at any given time,  based on our cash  exchange
     rates for each  currency  concerned),  we will inform you of this
     circumstance,  and you will be obligated to adopt the measures  necessary
     to reduce the  aggregate  debt of all the Borrowers  with the Lending
     Branches in order to adjust such to the Limit  specified  herein. You
     commit  yourselves  to making this  reduction  as soon as possible and in
     any event no later than five days following receipt of our communication.

4.   DOCUMENTATION: Each Lending Branch shall decide on the documentation it
     requires for each Borrower, which shall include, without limitation,
     evidence of the Borrower's capacity to bind itself in the transaction and
     the capacity of the authorized representatives. Each Borrower shall
     facilitate to each Lending Branch concerned those financial statements that
     the latter reasonably requires. Prior to the establishing of each
     sub-transaction with a Borrower, ABN AMRO must receive the required
     guaranties, if appropriate in accordance with Annex A, in the form shown in
     Annexes B and C (with such amendments that the Bank or the Lending Branch
     may reasonably require).

5.   NOTIFICATIONS:  Any notification and communication  relating to the
     Framework Agreement must be sent to the relevant party to the address set
     forth below:

THE COMPANY:                      ABENGOA, S.A.
                                  Avda. de la Buhaira, no. 2
                                  41018 Seville
                                  Attn.: Mr. Jesus Garcia Quilez
                                  Tel: 954 93 71 11
                                  Fax: 954 93 70 15

ABN AMRO                          ABN AMRO BANK N.V.,
                                  SUCURSAL EN ESPANA,
                                  C/Ortega y Gasset, 29- 5(a)planta
                                  28006 Madrid
                                  Attn.: Emilio Gomez
                                  Tel: 91 423 69 47
                                  Fax: 91 423 69 48

<PAGE>

6.   APPLICABLE LAW: The Framework Agreement and the Company's obligations
     shall be governed by Spanish Law. Each sub-transaction shall be governed by
     the law of the jurisdiction to which the relevant Lending Branch is
     subject, unless there is express agreement between the Lending Branch and
     the Borrower concerned.

Best regards,

ABN AMRO Bank, N.V.
Sucursal en Espana


/s/ Juan Martinez Aguilar                  /s/ Ignacio Madurga Garcia-Alegre
---------------------------------          -------------------------------------
Signed: Juan Martinez Aguilar              Signed: Ignacio Madurga Garcia-Alegre
Date: July 17, 2002                        Date: July 17, 2002


Accepted, agreed:
Abengoa, S.A.

/s/ Felipe Benjumea Llorente
---------------------------------
Signed: Felipe Benjumea Llorente
Date: July 17, 2002

<PAGE>
ABN-AMRO


                                     ANNEX A
<TABLE>
<CAPTION>
                                                                                    INITIAL SUB-TRANSACTIONS

------------------------------------------------------------------------------------------------------------
BORROWERS                           LIMIT              TRANSACTIONS                   GUARANTORS
------------------------------------------------------------------------------------------------------------
<S>                                 <C>                <C>                            <C>
1. Abengoa, S.A.                    20 million (Euro)  Coverage of exchange rate      None
                                                       risks/ interest rate or
                                                       others up to 20 million (Euro)
                                                       Current Account Credit up
                                                       to 5 million (Euro)
------------------------------------------------------------------------------------------------------------
2. Instalaciones Inabensa, S.A.     15 million (Euro)  'Avals' and Bank               Each of the Borrowers
Abener Energia, Ingenieria y                           Guarantees, coverage,          contained in this
Construccion Industrial, S.A.                          letters of credit, Import      Point 2 jointly and
Abentel Telecomunicaciones, S.A.                       Financing, discount,           severally
                                                       Current Account Credit
                                                       (up to 2 million (Euro))
------------------------------------------------------------------------------------------------------------
3. S.A. de Instalaciones de         30 million (Euro)  `Avals' and Bank Guarantees,   Each of the Borrowers
Control (Sainco)                                       coverage, letters of credit,   contained in this
Sainco Trafico, S.A.                                   Import Financing, discount,    point 3 jointly and
Sainsel Sistemas Navales, S.A.                         Current Account Credit         severally
Telvent Interactiva, S.A.                              (up to 3 million (Euro))
Carrier House, S.A.
------------------------------------------------------------------------------------------------------------
</TABLE>

N.B.: The amount in the operations of coverage in order to estimate the risk of
balancing item (riesgo de contrapartida) at any given time shall be calculated
in accordance with ABN AMRO's internal procedures.

<PAGE>
                                     ANNEX B
                                     -------

                                    GUARANTEE
                                    ---------

Pursuant to the Framework Agreement for the granting of banking transactions to
Abengoa Group,  dated July 17, 2002 (the "Framework Agreement") signed by
Abengoa, S.A. and ABN AMRO BANK N.V., Sucursal en Espana (the "Bank"), the Bank
and any other branches, offices or subsidiaries of ABN AMRO BANK N.V. can at any
moment grant banking transactions in favor of Instalaciones Inabensa, S.A.,
Abener Energia, Ingenieria y Construccion Industrial, S.A. and Abentel
Telecomunicaciones , S.A. (individually designated as a "Borrower" and jointly
as the "Borrowers").

The undersigned, Instalaciones Inabensa, S.A., Abener Energia, Ingenieria y
Construccion Industrial, S.A. and Abentel Telecomunicaciones, S.A (individually
designated as a "Guarantor" and jointly as the "Guarantors"), all of them
Borrowers and Guarantors, have been described in Annex A of the Framework
Agreement or designated as such in subsequent amendments thereto.

Furthermore, and in due accordance with the provisions laid down in the
Framework Agreement, each and every one of the obligations of each Borrower with
the Bank and with any Branch, office or subsidiary of ABN AMRO BANK, N.V. (the
Bank and each Branch, Office or subsidiary, hereinafter "Lending Branch") under
said Agreement has to be jointly and severally guaranteed by each and every
Guarantor together with each Borrower.

By virtue whereof:

1. The Guarantors, expressly waiving the benefits of priority, division and
excussion, hereby guarantee jointly and severally and with each one of the
Borrowers the total and punctual payment to each Lending Branch of all
obligations of each Borrower with each Lending Branch, doing so irrevocably and
unconditionally. This applies equally to existing transactions and such as may
be formalized in the future and to all the following types of obligations:
principal, interest, commission payments, redemption of debentures or any other
sums deriving from any of the sub-transactions of the Framework Agreement,
including any transaction effected under the aegis of an ISDA contract
(hereinafter, each and every one of them to be designated as the "Obligations")
and until such time as the Obligations guaranteed have been completely paid. The
books and registers of the particular Lending Branch in each case, recording the
sum of the Obligations of each Borrower, will certify the Borrower's Obligations
guaranteed hereunder. The liability of each Guarantor under this guarantee will
be joint and several with each other and with each Borrower. It will be absolute
and unconditional regardless of any defect of authenticity, validity, legality
or enforceability of any sub-transaction, document, agreement or instrument
relating to the obligations or any assignment thereof or the occurrence of a
"Country Risk Situation" or "New Currency Situation" (as defined later) so that
each Guarantor binds itself jointly and severally to compensate each Lending
Branch for any loss, cost or expense caused as a result of the aforementioned
defect of authenticity, validity, legality or enforceability of any
sub-transaction, document, agreement or instrument relative to the obligations
or any
<PAGE>

assignment thereof. This guarantee is open-ended in term and will remain in
force and oblige the Guarantors and their successors and assignees. The
Guarantor's liability hereunder will never exceed the sum of thirty million
euros (30,000,000 euros) or the equivalent thereof in other currencies at the
exchange rate laid down by the Bank, plus accrued interest and any other
charges, including, without limitation, monetary correction, where applicable,
and all mentioned costs and expenses.

For the purposes of this document:

"Country Risk Situation" means the following: a) the adoption of any law, rule
or regulation or action, or lack of action (de jure or de facto) by any
authority in the country of any Borrower that (i) modifies the Borrower's
obligations under the sub-transaction of said Borrower, (ii), modifies the
Borrower's tenure or control over its business and assets or (iii) prevents or
restricts the conversion or movement of the agreed currency, or b) the
occurrence of grounds of force majeure or the like that directly or indirectly
prevents or restricts the payment or transfer in the agreed currency of any sum
due under the sub-transaction in question into the account designated by the
Lending Branch in question or the free availability of said payments by the
Lending Branch in question.

"New Monetary Credit Situation" means any direct or indirect increase of a
Lending Branch's risk with the Borrower in question as a result of any law,
action or requirement by any authority (de jure or de facto).

2. ENCUMBRANCE OF ASSETS. The joint and several guarantors hereby guarantee the
sound performance of this contract with all their present or future assets,
especially those existing in their name in a Lending Branch. Should any or all
of the Guarantors breach their payment obligations, the Lending Branch is hereby
irrevocably authorized to offset pending payments against any cash deposits and
all types of credit rights, bills or securities that might be deposited in the
Lending Branch, as far as they may suffice for meeting the outstanding amounts.

3. INSOLVENCY OF THE BORROWER: This Guarantee shall remain in force if at any
time the payment or performance of any or all of the obligations of any Borrower
is terminated or the amount thereof is reduced as a consequence of insolvency,
suspension of payments, bankruptcy or reorganization of the Borrower concerned.
If by action of law the payment must be repaid or returned by the Lending Branch
concerned, the Guarantee shall come into force as if such payment had not been
made.

4. EXHAUSTING OF OTHER RESOURCES: Each Guarantor unconditionally waives any
right to require that a Lending Branch (a) claim against the Borrower or any
other debtor in relation to the Obligations, (b) claim against or exhaust any
direct or indirect guarantee that exists that guarantees the Obligations or (c)
attempt any other action to which the Lending Branch may have recourse. Absence
or delay on the part of any Lending Branch in the exercise of its rights,
faculties or privileges under this agreement does not signify a waiver thereof
nor does the individual or partial exercise of any of them exclude or prevent
the exercise of the remaining rights, faculties or privileges.

5. WAIVER OF NOTIFICATIONS: For all notifications, to which Article 573 of the
Spanish Civil Procedure Law refers, the Guarantor or Guarantors indicate what
has been already


<PAGE>


established, and accept the competent jurisdiction established by clause 8 of
this agreement. The addresses indicated are deemed effective until such time as
the Lending Branch is expressly notified in writing of any change. Pursuant to
the provisions of Article 573 of the Spanish Civil Procedure Law on
notifications, it is expressly agreed that such notifications can be given by
any means, including telefax or telegram.

6. AMENDMENTS. No amendment or waiver of any provision of this Guarantee shall
be effective without the consent in writing and the signature of the Bank.

7. PAYMENT OF EXPENSES: The Guarantor agrees to pay all legal fees reasonably
incurred, and likewise other costs and expenses which the Lending Branch may
reasonably incur in the execution of this Guarantee.

8. APPLICABLE LAW AND COURTS: This Guarantee and the rights and obligations of
the Guarantor, the Bank and each Lending Branch shall be subject to Spanish law
and any question derived therefrom shall be subject to the jurisdiction of the
courts of the city of Madrid, each and every one of the Guarantors waiving any
other forum that may correspond to them.

9. SUBROGATION. The Guarantor may not request repayment of any of the loans it
holds vis-a-vis any Borrower, granted under the Framework Agreement, until all
the obligations of this Borrower vis-a-vis any Lending Branch have been
satisfied in full


Seville, October 31, 2002


THE GUARANTORS
Instalaciones Inabensa, S.A.           Abener Energia, Ingenieria y Construccion
                                       Industrial, S.A.

Abentel Telecomunicaciones, S.A.



Accepted by
ABN Amro Bank, N.V.


<PAGE>
                                     ANNEX C
                                     -------

                                    GUARANTEE
                                    ---------

Pursuant to the Framework Agreement for the granting of banking transactions to
Abengoa Group, dated July 17, 2002 (the "Framework Agreement"), as amended on
January 13, 2003 and signed by Abengoa, S.A. and ABN AMRO BANK N.V., Sucursal en
Espana (the "Bank"), the Bank and any other branches, offices or subsidiaries of
ABN AMRO BANK N.V. can at any moment grant banking transactions in favor of S.A.
Instalaciones de Control (Sainco), Sainco Trafico S.A., Telvent Interactiva,
S.A., Telvent Sistemas y Redes, S.A., Sainsel Sistemas Navales, S.A. and
Carrierhouse, S.A. (individually designated as a "Borrower" and jointly as the
"Borrowers").

The undersigned, S.A. Instalaciones de Control (Sainco), Sainco Trafico S.A.,
Telvent Interactiva, S.A., Telvent Sistemas y Redes, S.A and Carrierhouse, S.A
(individually designated as a "Guarantor" and jointly as the "Guarantors"), all
of them Borrowers and Guarantors, have been described in Annex A of the
Framework Agreement or designated as such in subsequent amendments thereto.

Furthermore, and in due accordance with the provisions laid down in the
Framework Agreement, each and every one of the obligations of each Borrower with
the Bank and with any Branch, office or subsidiary of ABN AMRO BANK, N.V. (the
Bank and each Branch, Office or subsidiary, hereinafter "Lending Branch") under
said Agreement has to be jointly and severally guaranteed by each and every
Guarantor together with each Borrower.

By virtue whereof:

1. The Guarantors, expressly waiving the benefits of priority, division and
excussion, hereby guarantee jointly and severally and with each one of the
Borrowers the total and punctual payment to each Lending Branch of all
obligations of each Borrower with each Lending Branch, doing so irrevocably and
unconditionally. This applies equally to existing transactions and such as may
be formalized in the future and to all the following types of obligations:
principal, interest, commission payments, redemption of debentures or any other
sums deriving from any of the sub-transactions of the Framework Agreement,
including any transaction effected under the aegis of an ISDA contract
(hereinafter, each and every one of them to be designated as the "Obligations")
and until such time as the Obligations guaranteed have been completely paid. The
books and registers of the particular Lending Branch in each case, recording the
sum of the Obligations of each Borrower, will certify the Borrower's Obligations
guaranteed hereunder. The liability of each Guarantor under this guarantee will
be joint and several with each other and with each Borrower. It will be absolute
and unconditional regardless of any defect of authenticity, validity, legality
or enforceability of any sub-transaction, document, agreement or instrument
relating to the obligations or any assignment thereof or the occurrence of a
"Country Risk Situation" or "New Currency Situation" (as defined later) so that
each Guarantor binds itself jointly and severally to compensate each Lending
Branch for any loss, cost or expense caused as a result of the aforementioned
defect of authenticity, validity, legality or enforceability of any
sub-transaction, document, agreement or instrument relative to the obligations
or any


<PAGE>


assignment thereof. This guarantee is open-ended in term and will remain in
force and oblige the Guarantors and their successors and assignees. The
Guarantor's liability hereunder will never exceed the sum of thirty million
euros (30,000,000 euros) or the equivalent thereof in other currencies at the
exchange rate laid down by the Bank, plus accrued interest and any other
charges, including, without limitation, monetary correction, where applicable,
and all mentioned costs and expenses.

For the purposes of this document:

"Country Risk Situation" means the following: a) the adoption of any law, rule
or regulation or action, or lack of action (de jure or de facto) by any
authority in the country of any Borrower that (i) modifies the Borrower's
obligations under the sub-transaction of said Borrower, (ii), modifies the
Borrower's tenure or control over its business and assets or (iii) prevents or
restricts the conversion or movement of the agreed currency, or b) the
occurrence of grounds of force majeure or the like that directly or indirectly
prevents or restricts the payment or transfer in the agreed currency of any sum
due under the sub-transaction in question into the account designated by the
Lending Branch in question or the free availability of said payments by the
Lending Branch in question.

"New Monetary Credit Situation" means any direct or indirect increase of a
Lending Branch's risk with the Borrower in question as a result of any law,
action or requirement by any authority (de jure or de facto).

2. ENCUMBRANCE OF ASSETS. The joint and several guarantors hereby guarantee the
sound performance of this contract with all their present or future assets,
especially those existing in their name in a Lending Branch. Should any or all
of the Guarantors breach their payment obligations, the Lending Branch is hereby
irrevocably authorized to offset pending payments against any cash deposits and
all types of credit rights, bills or securities that might be deposited in the
Lending Branch, as far as they may suffice for meeting the outstanding amounts.

3. INSOLVENCY OF THE BORROWER: This Guarantee shall remain in force if at any
time the payment or performance of any or all of the obligations of any Borrower
is terminated or the amount thereof is reduced as a consequence of insolvency,
suspension of payments, bankruptcy or reorganization of the Borrower concerned.
If by action of law the payment must be repaid or returned by the Lending Branch
concerned, the Guarantee shall come into force as if such payment had not been
made.

4. EXHAUSTING OF OTHER RESOURCES: Each Guarantor unconditionally waives any
right to require that a Lending Branch (a) claim against the Borrower or any
other debtor in relation to the Obligations, (b) claim against or exhaust any
direct or indirect guarantee that exists that guarantees the Obligations or (c)
attempt any other action to which the Lending Branch may have recourse. Absence
or delay on the part of any Lending Branch in the exercise of its rights,
faculties or privileges under this agreement does not signify a waiver thereof
nor does the individual or partial exercise of any of them exclude or prevent
the exercise of the remaining rights, faculties or privileges.

5. WAIVER OF NOTIFICATIONS: For all notifications, to which Article 573 of the
Spanish Civil Procedure Law refers, the Guarantor or Guarantors indicate what
has been already

<PAGE>

established, and accept the competent jurisdiction established by clause 8 of
this agreement. The addresses indicated are deemed effective until such time as
the Lending Branch is expressly notified in writing of any change. Pursuant to
the provisions of Article 573 of the Spanish Civil Procedure Law on
notifications, it is expressly agreed that such notifications can be given by
any means, including telefax or telegram.

6. AMENDMENTS. No amendment or waiver of any provision of this Guarantee shall
be effective without the consent in writing and the signature of the Bank.

7. PAYMENT OF EXPENSES: The Guarantor agrees to pay all legal fees reasonably
incurred, and likewise other costs and expenses which the Lending Branch may
reasonably incur in the execution of this Guarantee.

8. APPLICABLE LAW AND COURTS: This Guarantee and the rights and obligations of
the Guarantor, the Bank and each Lending Branch shall be subject to Spanish law
and any question derived therefrom shall be subject to the jurisdiction of the
courts of the city of Madrid, each and every one of the Guarantors waiving any
other forum that may correspond to them.

9. SUBROGATION. The Guarantor may not request repayment of any of the loans it
holds vis-a-vis any Borrower, granted under the Framework Agreement, until all
the obligations of this Borrower vis-a-vis any Lending Branch have been
satisfied in full



Madrid, January 13, 2003
THE GUARANTORS

S.A. Instalaciones de Control (Sainco)              Sainco Trafico, S.A.

Telvent Interactiva, S.A.                           Carrierhouse, S.A.

Telvent Sistemas y Redes, S.A.


Accepted by
ABN Amro Bank, N.V.