A $1 billion solar project near Las Vegas may help light up the Strip and other parts of Nevada, California and Arizona as early as 2020.

The proposed Gemini solar project would be one of the largest in the western U.S., located on almost 44,000 acres of federal land about 25 miles (40 kilometers) northeast of downtown Las Vegas, according to a statement Monday from developer Quinbrook Infrastructure Partners. The company is planning to install 690 megawatts of solar and as much as 200 megawatts of batteries.

A key element of the project is the batteries. Solar-storage projects are capable of delivering power when the sun has set. That’s become especially important across the western U.S. With battery costs falling, electricity buyers in California are increasingly seeking solar coupled with batteries as well.

“In California, I’d sincerely doubt you’d build a solar project without a battery,” Jeff Hunter, senior managing director of Quinbrook, said in an interview.

Quinbrook, with U.S. headquarters in Houston, said an environmental review is expected to be completed next year, with construction slated to begin in the third quarter of 2019. Arevia Power will oversee final development and construction, and the final cost will be dictated by the size of the project’s battery component, Hunter said.

Quinbrook has begun seeking contracts to sell output from the project, which consist of two phases. Power could begin flowing from the plant as soon as 2020.

Gemini is among a spate of large U.S. solar projects proposed recently, in part to capture governmental incentives before they’re scheduled to wane, said Hugh Bromley, a New York-based analyst at Bloomberg NEF.