Tesla’s new solar energy storage facility on the Hawaiian island of Kauai does what most solar power plants cannot: it stores energy from the sun during peak times for use when the grid (and its customers) needs it most. The facility is unique, with 52 MWh of storage capacity and 13 MWh of generation via its field of panels.

We spoke to Tesla CTO and co-founder JB Straubel, who oversees the company’s commercial energy concerns as part of his expanded role now that Tesla owns SolarCity, the solar power company it acquired late last year. Straubel explains that this Kauai plant is a proof point for Tesla: The company has now demonstrated that it can provide this kind of solution at a scale where it’s useful to utilities around the world, not just on sun-drenched islands in the Pacific.