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EXHIBIT 10.6

EXTENSION AGREEMENT
May 31, 2019
Wells Fargo Bank, National Association, as Administrative Agent under the Credit
Agreement referred to below

Wells Fargo Bank, National Association
90 S. 7th Street
MAC: N9305-156
Minneapolis, MN 55402
Attention: Greg Gredvig
Phone: (612) 667-4832
Fax No.: (612) 316-0506

Ladies and Gentlemen:

Reference is made to (i) the Third Amended and Restated Credit Agreement, dated
as of April 30, 2018 (as amended, restated, modified or otherwise supplemented
from time to time prior to the date hereof, the “Credit Agreement”), among
Sierra Pacific Power Company, a Nevada corporation (the “Borrower”), the banks
and other financial institutions party thereto as Lenders, and Wells Fargo Bank,
National Association, as Administrative Agent, and (ii) the Borrower’s
Termination Date Extension Request, dated April 15, 2019, requesting an
extension of the Termination Date to June 30, 2022 (the “Extension Request”).
Unless otherwise indicated, capitalized terms used herein and not otherwise
defined herein have the meanings given such terms in the Credit Agreement.

Solely in connection with the extension of the Termination Date to June 30, 2022
as set forth in the Extension Request, each undersigned Lender agrees, subject
to the Administrative Agent’s receipt of the documents described in Section
2.06(c) of the Credit Agreement, to extend the Termination Date applicable to
such Lender’s Commitment to June 30, 2022, such extension to be effective on May
31, 2019. The undersigned Lenders, constituting Required Lenders, hereby waive
the time period requirements set forth in Section 2.06(a) of the Credit
Agreement for each Lender to provide notice of such Lender’s decision to consent
to, or decline, the extension of the Termination Date to June 30, 2022. The
Required Lenders hereby agree that (a) this Extension Agreement shall be dated
as of the date first set forth above, (b) the deadline for each consenting
Lender to provide a signature page to this Extension Agreement is May 6, 2019,
and (c) subject to the Administrative Agent’s receipt of the documents described
in Section 2.06(c) of the Credit Agreement, the “Extension Effective Date” with
respect to the Extension Request shall be May 31, 2019.

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Furthermore, each of the undersigned Lenders that is an LC Issuing Bank as of
the date hereof agrees to continue to serve as an LC Issuing Bank in accordance
with its Fronting Commitment after giving effect to the extension of the
Termination Date as set forth herein.

This Extension Agreement shall be construed in accordance with and governed by
the law of the State of New York. This Extension Agreement is a Loan Document.
Except as specifically provided above, (i) the Credit Agreement and the other
Loan Documents shall remain in full force and effect and are hereby ratified and
confirmed in all respects by the parties hereto, and (ii) the execution and
delivery of this Extension Agreement shall not operate as a waiver of any right,
power or remedy of the Administrative Agent or any Lender under the Credit
Agreement or any Loan Documents, nor constitute a waiver of any provision of the
Credit Agreement or any Loan Documents. This Extension Agreement may be signed
in any number of counterparts, each of which shall be an original, with the same
effect as if the signatures thereto and hereto were upon the same instrument.

[Signature pages follow]

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The Bank of Nova Scotia

By: /s/ David Dewar
Name: David Dewar
Title: Director

Extension Agreement – Sierra Pacific Power Company (2019)

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SUMITOMO MITSUI BANKING
CORPORATION
 
By: /s/ Katsuyuki Kubo
Name: Katsuyuki Kubo
Title: Managing Director

Extension Agreement – Sierra Pacific Power Company (2019)

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JPMORGAN CHASE BANK, N.A.

By: /s/ Juan Javellana
Name: Juan Javellana
Title: Executive Director

Extension Agreement – Sierra Pacific Power Company (2019)

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BNP Paribas

By: /s/ Denis O' Meara
Name: Denis O' Meara
Title: Managing Director

By: /s/ Ravina Advani
Name: Ravina Advani
Title: Managing Director

Extension Agreement – Sierra Pacific Power Company (2019)

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BARCLAYS BANK PLC

By: /s/ Sydney G. Dennis
Name: Sydney G. Dennis
Title: Director

Extension Agreement – Sierra Pacific Power Company (2019)

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Royal Bank of Canada

By: /s/ Frank Lambrinos
Name: Frank Lambrinos
Title: Authorized Signatory

Extension Agreement – Sierra Pacific Power Company (2019)

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CANADIAN IMPERIAL BANK OF
COMMERCE, NEW TORK BRANCH, as
Lender

By: /s/ Robert Casey
Name: Robert Casey
Title: Authorized Signatory

By: /s/ Farhad Merali
Name: Farhad Merali
Title: Authorized Signatory

Extension Agreement – Sierra Pacific Power Company (2019)

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MUFG UNION BANK, N.A.,

By: /s/ Cherese Joseph
Name: Cherese Joseph
Title: Vice President

Extension Agreement – Sierra Pacific Power Company (2019)

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CoBank, ACB

By: /s/ Ryan Spearman
Name: Ryan Spearman
Title: Vice President

Extension Agreement – Sierra Pacific Power Company (2019)

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The Bank of New York Mellon

By: /s/ Richard K. Fronapfel, Jr.
Name: Richard K. Fronapfel, Jr.
Title: Director

Extension Agreement – Sierra Pacific Power Company (2019)

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TD BANK, N.A.

By: /s/ Vijay Prasad
Name: Vijay Prasad
Title: Sr. Vice President

Extension Agreement – Sierra Pacific Power Company (2019)

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SUNTRUST BANK

By: /s/ Carmen Malizia
Name: Carmen Malizia
Title: Director

Extension Agreement – Sierra Pacific Power Company (2019)

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PNC BANK, NATIONAL ASSOCIATION,
as Lender

By: /s/ Kelly Miller
Name: Kelly Miller
Title: Vice President

Extension Agreement – Sierra Pacific Power Company (2019)

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The Northern Trust Company

By: /s/ Lisa DeCristofaro
Name: Lisa DeCristofaro
Title: SVP

Extension Agreement – Sierra Pacific Power Company (2019)

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National Australia Bank Limited

By: /s/ Eli Davis
Name: Eli Davis
Title: Director

Extension Agreement – Sierra Pacific Power Company (2019)

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KeyBank National Association

By: /s/ Benjamin C. Cooper
Name: Benjamin C. Cooper
Title: Vice President

Extension Agreement – Sierra Pacific Power Company (2019)

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MIZUHO BANK, LTD.

By: /s/ Donna DeMagistris
Name: Donna DeMagistris
Title: Authorized Signatory

Extension Agreement – Sierra Pacific Power Company (2019)

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CITIBANK, N.A.

By: /s/ Richard Rivera
Name: Richard Rivera
Title: Vice President

Extension Agreement – Sierra Pacific Power Company (2019)

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AGREED AND ACCEPTED:

SIERRA PACIFIC POWER COMPANY

By: /s/ Michael E. Cole
Name: Michael E. Cole
Title: Vice President and Chief Financial Officer

Extension Agreement – Sierra Pacific Power Company (2019)

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U.S. Bank National Association

By: /s/ Kevin Murphy
Name: Kevin Murphy
Title: Vice President

Extension Agreement – Sierra Pacific Power Company (2019)

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Bank of Montreal, Chicago Branch

By: /s/ Brian L. Banke
Name: Brian L. Banke
Title: Managing Director

Extension Agreement – Sierra Pacific Power Company (2019)

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Banco Santander, S.A., New York Branch

By: /s/ Rita Walz-Cuccioli
Name: Rita Walz-Cuccioli
Title: Executive Director

By: /s/ Terence Corcoran
Name: Terence Corcoran
Title: Executive Director

Extension Agreement – Sierra Pacific Power Company (2019)

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WELLS FARGO BANK, NATIONAL ASSOCIATION
as Administrative Agent, an LC Issuing Bank
and a Lender

By: /s/ Gregory R. Gredvig
Name: Gregory R. Gredvig
Title: Director