The Royal Slope Energy Center is a large-scale renewable energy facility being developed in Grant County, Washington. Spearheaded by Clearway Energy Group, the project features a 260 MW solar farm paired with a 260 MW (4-hour) battery energy storage system. It recently secured a 20-year Power Purchase Agreement (PPA) with the Grant County Public Utility District to support regional grid reliability and clean energy targets. Situated near the Vantage Substation, the facility is expected to create over 325 construction jobs and begin commercial operations by late 2027, generating enough electricity to power approximately 87,000 homes.
California-based Clearway Energy Group has signed a 20-year power purchase agreement (PPA) and a 20-year energy storage contract with the Public Utility District No. 2 (Grant PUD) of Grant County, Washington. The agreement, announced on November 4, 2025, covers power generated from the Royal Slope Energy Center, a 260-MW solar and 260-MW battery storage facility located in central Washington. The project is expected to reach commercial operation by the end of 2027.
Strengthening Washington’s Clean Energy Portfolio
Royal Slope is part of Clearway’s expanding Washington portfolio, which already includes the 160-MW Rattlesnake Flat Wind Farm in Adams County and the 137-MW Tuolumne Wind Farm in Klickitat County—a region seeing continued renewable activity as the Washington Governor approves the 160MW Carriger Solar Farm in Klickitat County. Interestingly in Grant County in the same state a moratorium exists on the development of solar projects that has hampered development in the county and may have contributed to slowing projects like the Black Rock solar project that has not yet been constructed 3 years after receiving approvals.
According to Valerie Wooley, Senior Vice President of Origination at Clearway Energy, the partnership aligns with the state’s clean energy goals and growing electricity demand:
“This partnership with Grant PUD reflects our shared vision to bring reliability and near-term power supply to regions experiencing significant load growth from data centers and industrial demand. Royal Slope is a long-term investment in Washington’s energy independence and economic vitality.”
Supporting Grant PUD’s Energy and Reliability Goals
Grant PUD’s 2024 Integrated Resource Plan (IRP) identified urgent energy and capacity needs to ensure reliable service while meeting Washington State’s carbon reduction goals.
The Royal Slope agreements will help Grant PUD meet its near-term solar and storage targets by 2028 and advance progress toward power-acquisition needs through 2030.
Economic and Community Benefits
Once operational, the Royal Slope Energy Center will produce enough clean electricity to power approximately 87,000 homes.
The project will connect via the Vantage Substation, leveraging existing Bonneville Power Administration (BPA) transmission infrastructure.
During construction, more than 325 union laborers are expected to be employed. The project is projected to generate $130 million in state and local tax revenue, supporting education, emergency services, and local infrastructure.
Project Factsheet: Royal Slope Energy Center
Location: Grant County, Washington
Developer: Clearway Energy Group
Technology: 260 MW Solar + 260 MW Battery Storage
Offtaker: Public Utility District No. 2 of Grant County (Grant PUD)
Contract Term: 20-year PPA + 20-year storage agreement
Expected COD: End of 2027
Homes Powered: ~87,000
Economic Impact: $130 million in state and local taxes
Jobs Created: 325+ union construction jobs
Transmission: Vantage Substation (BPA network)
Related Projects: Rattlesnake Flat Wind Farm (160 MW), Tuolumne Wind Farm (137 MW)
