$250,000,000 Third Amended and Restated Credit Agreement, dated as of May 31, 2019, among Sierra Pacific Power Company, as Borrower, the Banks, Financial Institutions and Other Institutional Lenders, as Initial Lenders, Wells Fargo Bank, National Association, as Administrative Agent and the LC Issuing Banks

Wells Fargo Bank, National Association, as Administrative Agent under the Credit Agreement referred to below

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.

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.

By: /s/ David Dewar

Name: David Dewar

Title: Director

By: /s/ Katsuyuki Kubo

Name: Katsuyuki Kubo

Title: Managing Director

By: /s/ Juan Javellana

Name: Juan Javellana

Title: Executive Director

By: /s/ Denis O' Meara

Name: Denis O' Meara

Title: Managing Director

By: /s/ Ravina Advani

Name: Ravina Advani

Title: Managing Director

By: /s/ Sydney G. Dennis

Name: Sydney G. Dennis

Title: Director

By: /s/ Frank Lambrinos

Name: Frank Lambrinos

Title: Authorized Signatory

By: /s/ Robert Casey

Name: Robert Casey

Title: Authorized Signatory

By: /s/ Farhad Merali

Name: Farhad Merali

Title: Authorized Signatory

By: /s/ Cherese Joseph

Name: Cherese Joseph

Title: Vice President

By: /s/ Ryan Spearman

Name: Ryan Spearman

Title: Vice President

By: /s/ Richard K. Fronapfel, Jr.

Name: Richard K. Fronapfel, Jr.

Title: Director

By: /s/ Vijay Prasad

Name: Vijay Prasad

Title: Sr. Vice President

By: /s/ Carmen Malizia

Name: Carmen Malizia

Title: Director

as Lender

By: /s/ Kelly Miller

Name: Kelly Miller

Title: Vice President

By: /s/ Lisa DeCristofaro

Name: Lisa DeCristofaro

Title: SVP

By: /s/ Eli Davis

Name: Eli Davis

Title: Director

By: /s/ Benjamin C. Cooper

Name: Benjamin C. Cooper

Title: Vice President

By: /s/ Donna DeMagistris

Name: Donna DeMagistris

Title: Authorized Signatory

By: /s/ Richard Rivera

Name: Richard Rivera

Title: Vice President

By: /s/ Michael E. Cole

Name: Michael E. Cole

Title: Vice President and Chief Financial Officer

By: /s/ Kevin Murphy

Name: Kevin Murphy

Title: Vice President

By: /s/ Brian L. Banke

Name: Brian L. Banke

Title: Managing Director

By: /s/ Rita Walz-Cuccioli

Name: Rita Walz-Cuccioli

Title: Executive Director

By: /s/ Terence Corcoran

Name: Terence Corcoran

Title: Executive Director

By: /s/ Gregory R. Gredvig

Name: Gregory R. Gredvig

Title: Director