Dive Brief:

• NV Energy subsidiary Sierra Pacific Power Co. plans to continue operating the 522 MW North Valmy coal-fired plant through 2025, despite concluding the early retirement of one unit would be a cheaper option.
• Last year, Idaho Power indicated it wants to shutter the units in 2019 and 2025 respectively, a decade sooner than originally planned, saying it would not benefit consumers past 2025. But the Idaho utility will need to make that decision along with co-owner NV Energy. 
• According to the Sierra Club, if NV Energy were to close Unit 1 in 2019 and replace it with renewable energy, customers could see $30 million in benefit.

Dive Insight:

Idaho Power and NV Energy subsidiary Sierra Pacific Power will need to reach some agreement on how and when to close Valmy. There are several scenarios that complicate matters, but in essence, Idaho Power wants to close Unit 1 in 2019 and Unit 2 in 2025. Sierra Pacific wants to continue operating both through 2025.

Sierra Pacific Power recently filed a Life Span Analysis Process (LSAP) for the plant, fulfilling a request from Nevada regulators. The utility concluded closing down one unit early and replacing it with 330 MW of solar is the lowest cost option. Sierra Club said its analysis found that operating both of Valmy’s coal units through 2025 would cost utility customers $30 million more.

But while customers might save money, the utility said there are risks. Cases where Unit 1 is retired early "have the largest open positions among the cases studied ... and therefore the greatest exposure to market price fluctuations and potential for energy shortages," the utility told regulators. Sierra Pacific noted that small delays in constructing solar farms could boost the cost. 

Officials from Sierra Club, however, said the decision shows the utility's commitment to coal.

Elspeth DiMarzio, a Sierra Club campaign representative in Nevada, said in a statement, "this should be an easy decision. It is hard to take NV Energy's rhetoric about clean energy seriously when they remain committed to an expensive old coal plant."

North Valmy is the last utility-owned coal plant in Nevada. NV Energy closed down the Reid Gardner plant closed in March of last year.