With little fanfare or discussion, Nevada regulators have approved a major energy supply plan that will result in construction of six major solar projects and conditionally retire one of the state’s two remaining coal-firing power plants by 2021.

The three members of the Public Utilities Commission voted unanimously on Friday to approve the final portion of NV Energy’s Integrated Resource Plan (IRP), the state-mandated planning document on electric supply and demand required to be filed every three years.

First filed in June, the approved IRP allows the electric utility to enter into power purchase agreements with six planned solar photovoltaic plants across the state, with a total capacity of 1,001 megawatts. Power purchase agreements are exclusive contracts between private developers and utilities to purchase regular amounts of electricity from power plants at a typically fixed price over a period of several years.

The new plants will double the state’s renewable energy capacity and solar production by 2023, substantially increasing the state’s reliance on renewable energy. The order also authorizes 100 megawatts of energy storage to be built at a handful of the plants.

In a statement, utility president Doug Cannon said the approved order was the largest “renewable energy investment” in state history, and helped the company on its goal to substantially raise renewable production.

“Earlier this year we made a promise to our customers that we would double our renewable energy by 2023 and today’s decision puts us closer to reaching that goal, as well as to our long-term commitment to serve them with 100 percent renewable energy,” Cannon said in a statement.

The approved order also calls for a conditional retirement of one of the units at the coal-firing Valmy Generating Station, which is jointly owned by NV Energy and Idaho Power. The conditional retirement date is set for the end of 2021, but is dependent on several factors including construction of the new power plants proceeding as scheduled and having enough capacity to serve customers.

Outside of a nonprofit group backed by Switch, few parties had substantial criticism or opposed the utility’s planned IRP in proceedings before the commission, and its adoption was met with plaudits by renewable advocates who welcomed news of the coal plants’ scheduled retirement.

“The early retirement schedule for the North Valmy coal plant marks a major milestone in Nevada’s transition to clean energy,” said Sierra Club for Nevada spokeswoman Elspeth DiMarzio said in a statement. “NV Energy’s shift from coal to low cost clean energy will save millions of dollars for families and businesses across Nevada while also clearing our air of more toxic coal pollution.”

Other advocates, including Western Resource Advocates attorney Robert Johnston, said approval of the order would lower carbon emissions and line the state up to meet a potentially higher Renewable Portfolio Standard if a ballot question raising it to 50 percent by 2030 is approved by voters in 2020.

“NV Energy’s IRP will develop our state’s abundant solar resources while significantly reducing the utility’s carbon emissions, which are a key driver of climate change,” he said in a statement.

In its testimony, NV Energy warned that approval of the plan and construction of the six new power plants would “negatively affect credit quality,” of the utility given the cost to construct the plants, stating that it could request higher rates in future proceedings before regulators.

The order also granted permission for NV Energy to spend up to $22.89 million on transmission upgrades and extended out scheduled retirement dates of eight natural gas into the late 2020’s and early 2030’s.