Document:

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                                                                   EXHIBIT 10.20

                            [ENRON CORP. LETTERHEAD]

April 29, 1997

Northern Border Pipeline Company
1111 South 103rd Street
P.O. Box 3330 (Zip: 68103-0330)
Omaha, Nebraska 68124-1000

Dear Ladies and Gentlemen:

                                GUARANTY (T1060F)

As an inducement to Northern Border Pipeline Company (hereinafter "Northern
Border") to grant credit, or assume a credit risk, from time to time, in respect
to transportation of gas by Northern Border pursuant to a U.S. Shippers Service
Agreement T1060F (the "Agreement"), which Agreement is identical to or
substantially the same as the copy attached hereto, for the benefit of Enron
Capital & Trade Resources Corp. (hereinafter the "Shipper"), Enron Corp.
(hereinafter the "Guarantor"), shall pay to Northern Border promptly when due,
or upon demand thereafter the full amount of all indebtedness due to Northern
Border from Shipper, pursuant to Article 4 of the Agreement (including interest
and expenses of all collection and reasonable counsel's fees incurred by
Northern Border by reason of the default of Shipper), up to an annual aggregate
amount of U.S. $12,600,000.00 during each year that the Agreement remains in
effect.

This Guaranty by Guarantor shall remain in full force and effect during the term
of the Agreement, and any extension or renewal thereof and thereafter until
Shipper has fully performed all of its obligations under the Agreement. This
Guaranty applies to all successors and/or assigns of Shipper; provided, however,
that in the event Shipper is released pursuant to the Agreement and Northern
Border's FERC Gas Tariff by Northern Border from its obligations under the
Agreement, the Guarantor shall have the right to cancel this Guaranty by written
notice to Northern Border on or after the effective date of such release.

Guarantor waives notice of acceptance hereof and notice of the volumes of gas
transported by Northern Border for the benefit of Shipper, and of the amounts
and terms thereof, and of all defaults or disputes with Shipper, and of the
settlement or adjustment of such defaults

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or disputes. The Guarantor, without affecting its liability hereunder in any
respect, consents to and waives notice of all changes of terms, the withdrawal
of extension of credit or time to pay, the release of the whole or any part of
the indebtedness, the settlement or compromise of differences, the acceptance or
release of security, the acceptance of notes, or any other form of obligation
for Shipper's indebtedness, and the demand, protest and notice of protest of
such instruments or their endorsements.

The obligation of the Guarantor is a primary obligation and covers the payment
of all existing and future indebtedness obligations of Shipper to Northern
Border under the Agreement. This obligation shall be enforceable before or after
proceeding against Shipper or against any security held by Northern Border and
shall be effective regardless of the solvency or insolvency of Shipper at any
time, the extension or modification of the indebtedness of Shipper by operation
of law or the subsequent incorporation, reorganization, merger or consolidation
of Shipper or any other change in the composition, nature, personnel or location
of Shipper.

THIS GUARANTY SHALL FOR ALL PURPOSES BE DEEMED TO BE MADE IN, AND SHALL BE
GOVERNED BY, THE LAWS OF THE STATE OF TEXAS. This Guaranty shall be binding upon
Guarantor, its successors and assigns and shall inure to the benefit of Northern
Border, its successors and assigns.

Guarantor reserves to itself all rights, setoffs, counterclaims and other
defenses, if any, which Shipper is or may be entitled to arising from or out of
the Agreement and/or Northern Border's FERC Gas Tariff.

Guarantor's liability under this Guaranty shall be limited to direct, actual,
monetary damages under the Agreement; provided that, in no event will Guarantor
be subject to consequential, exemplary, equitable, loss of profits, tort or any
other damages.

The Guarantor in executing this Guaranty, represents and warrants to Northern
Border that:

                  (i) The Guarantor is a corporation duly organized and existing
         in good standing and has full power and authority to make and deliver
         this Guaranty;

                  (ii) The execution and delivery and performance of this
         Guaranty by the Guarantor has been duly authorized by all necessary
         action of its directors and shareholders and does not violate the
         provisions of any presently applicable law or its articles of
         incorporation or by-laws or constitute a default under any material
         ("material" for purposes of this representation meaning creating a
         liability of U.S. $50,000,000 or more) agreement presently binding on
         it; and

                  (iii) This Guaranty has been duly executed and delivered by
         the authorized officers of the Guarantor and constitutes its lawful,
         binding and legally enforceable obligation, except as such
         enforceability may be limited by the effect of any applicable
         bankruptcy, insolvency, reorganization, moratorium or similar laws
         affecting creditors rights generally and by general principles of
         equity.

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IN WITNESS WHEREOF, this Guaranty has been duly executed William D. Gathmann,
Vice President, Finance and Treasurer of the Guarantor this 29th day of April,
1997.

"GUARANTOR"

Enron Corp.                                   Attest:

BY:      /s/ William D. Gathmann                    /s/ Kate B. Cole
     --------------------------------      ------------------------------------
         William D. Gathmann                        Kate B. Cole
         Vice President, Finance                    Assistant Secretary
         and Treasurer

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                              GUARANTY CONFIRMATION

         This Guaranty Confirmation agreement (the "Confirmation"), dated as of
the 19th day of November, 1998, is made by Enron Corp. ("Guarantor") in favor
of Northern Border Pipeline Company (the "Company").

         WHEREAS, Guarantor and the Company entered into the Guaranty, dated
April 29, 1997, (the "Guaranty") pursuant to which Guarantor agreed to guarantee
the timely payment and performance of the obligations of Enron Capital & Trade
Resources Corp. ("ECTR"), a wholly owned subsidiary of Guarantor, under U.S.
Shippers Service Agreement (T1060F), dated August 5, 1997, as amended and
supplemented from time to time, ("Service Agreement"); and

         WHEREAS, ECTR desires to increase the Service Agreement for an
additional 2,500 Mcf/d and Guarantor desires to guarantee all amounts,
obligations and liabilities related to this additional 2,500 Mcf/d under the
Guaranty; and

         WHEREAS, it is a condition of Company in executing the Amendment to the
Service Agreement that the Guarantor execute and deliver this Confirmation; and

         WHEREAS, the execution, delivery, and performance of this Confirmation
is reasonably expected to benefit Guarantor, directly or indirectly.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Guarantor hereby agrees as
follows:

1. Guarantor hereby consents to the execution, delivery and performance of the
Amendment.

2. Guarantor hereby agrees, ratifies and confirms that the amounts, obligations
and liabilities guaranteed by the Guaranty include the amended amounts,
obligations and liabilities of the Amendment.

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3. Guarantor hereby represents and warrants that it has received, or will
receive, direct or indirect benefit from its prior execution, delivery, and
performance of the Guaranty, as hereby ratified and confirmed.

4. The Guaranty is hereby ratified and confirmed and all of the rights, powers
and privileges created by or under the Guaranty shall be and remain in full
force and effect. The execution, delivery and performance of this Confirmation
shall not, except as otherwise expressly provided in this Confirmation, operate
as a waiver of any right, power, or remedy of the Company under any of the terms
or conditions of the Guaranty.

5. This Confirmation may be executed in any number of counterparts, each of
which shall be an original, but all of which when taken together shall
constitute one instrument.

         IN WITNESS WHEREOF, Guarantor has caused this Confirmation to be
executed and delivered as of the date first above written.

ENRON CORP.

By:      /s/
     -------------------------------

By:
     -------------------------------<PAGE>
                                                                   EXHIBIT 10.22

                            [ENRON CORP. LETTERHEAD]

April 29, 1997

Northern Border Pipeline Company
1111 South 103rd Street
P.O. Box 3330 (Zip: 68103-0330)
Omaha, Nebraska 68124-1000

Dear Ladies and Gentlemen:

                                GUARANTY (T1061F)

As an inducement to Northern Border Pipeline Company (hereinafter "Northern
Border") to grant credit, or assume a credit risk, from time to time, in respect
to transportation of gas by Northern Border pursuant to a U.S. Shippers Service
Agreement T1061F (the "Agreement"), which Agreement is identical to or
substantially the same as the copy attached hereto, for the benefit of Enron
Capital & Trade Resources Corp. (hereinafter the "Shipper"), Enron Corp.
(hereinafter the "Guarantor"), shall pay to Northern Border promptly when due,
or upon demand thereafter the full amount of all indebtedness due to Northern
Border from Shipper, pursuant to Article 4 of the Agreement (including interest
and expenses of all collection and reasonable counsel's fees incurred by
Northern Border by reason of the default of Shipper), up to an annual aggregate
amount of U.S. $5,400,000.00 during each year that the Agreement remains in
effect.

This Guaranty by Guarantor shall remain in full force and effect during the term
of the Agreement, and any extension or renewal thereof and thereafter until
Shipper has fully performed all of its obligations under the Agreement. This
Guaranty applies to all successors and/or assigns of Shipper; provided, however,
that in the event Shipper is released pursuant to the Agreement and Northern
Border's FERC Gas Tariff by Northern Border from its obligations under the
Agreement, the Guarantor shall have the right to cancel this Guaranty by written
notice to Northern Border on or after the effective date of such release.

Guarantor waives notice of acceptance hereof and notice of the volumes of gas
transported by Northern Border for the benefit of Shipper, and of the amounts
and terms thereof, and of all defaults or disputes with Shipper, and of the
settlement or adjustment of such defaults or disputes. The Guarantor, without
affecting its liability hereunder in any respect, consents to and

<PAGE>

waives notice of all changes of terms, the withdrawal of extension of credit or
time to pay, the release of the whole or any part of the indebtedness, the
settlement or compromise of differences, the acceptance or release of security,
the acceptance of notes, or any other form of obligation for Shipper's
indebtedness, and the demand, protest and notice of protest of such instruments
or their endorsements.

The obligation of the Guarantor is a primary obligation and covers the payment
of all existing and future indebtedness obligations of Shipper to Northern
Border under the Agreement. This obligation shall be enforceable before or after
proceeding against Shipper or against any security held by Northern Border and
shall be effective regardless of the solvency or insolvency of Shipper at any
time, the extension or modification of the indebtedness of Shipper by operation
of law or the subsequent incorporation, reorganization, merger or consolidation
of Shipper or any other change in the composition, nature, personnel or location
of Shipper.

THIS GUARANTY SHALL FOR ALL PURPOSES BE DEEMED TO BE MADE IN, AND SHALL BE
GOVERNED BY, THE LAWS OF THE STATE OF TEXAS. This Guaranty shall be binding upon
Guarantor, its successors and assigns and shall inure to the benefit of Northern
Border, its successors and assigns.

Guarantor reserves to itself all rights, setoffs, counterclaims and other
defenses, if any, which Shipper is or may be entitled to arising from or out of
the Agreement and/or Northern Border's FERC Gas Tariff.

Guarantor's liability under this Guaranty shall be limited to direct, actual,
monetary damages under the Agreement; provided that, in no event will Guarantor
be subject to consequential, exemplary, equitable, loss of profits, tort or any
other damages.

The Guarantor in executing this Guaranty, represents and warrants to Northern
Border that:

(i)      The Guarantor is a corporation duly organized and existing in good
         standing and has full power and authority to make and deliver this
         Guaranty;

(ii)     The execution and delivery and performance of this Guaranty by the
         Guarantor has been duly authorized by all necessary action of its
         directors and shareholders and does not violate the provisions of any
         presently applicable law or its articles of incorporation or by-laws or
         constitute a default under any material ("material" for purposes of
         this representation meaning creating a liability of U.S. $50,000,000 or
         more) agreement presently binding on it; and

(iii)    This Guaranty has been duly executed and delivered by the authorized
         officers of the Guarantor and constitutes its lawful, binding and
         legally enforceable obligation, except as such enforceability may be
         limited by the effect of any applicable bankruptcy, insolvency,
         reorganization, moratorium or similar laws affecting creditors rights
         generally and by general principles of equity.

<PAGE>

IN WITNESS WHEREOF, this Guaranty has been duly executed William D. Gathmann,
Vice President, Finance and Treasurer of the Guarantor this 29th day of April,
1997.

"GUARANTOR"

Enron Corp.                                     Attest:

BY:      /s/ William D. Gathmann                        /s/Kate B. Cole
     -----------------------------------       --------------------------------
         William D. Gathmann                            Kate B. Cole
         Vice President, Finance                        Assistant Secretary
         and Treasurer

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