Tesla CEO Elon Musk’s battery-making dreams are finally coming true with the start of operations at the company’s Gigafactory in Reno, NV.

Though the factory is only a third complete at the moment, it’s already churning out solar-based battery cells on a mass scale, as of today, the company announced. The batteries will be used in Tesla’s Powerwall system for homes (see photo above), its Powerpack business system, and eventually, batteries for its promised Model 3 vehicles.

Tesla claims that its Gigafactory will double world’s production capacity for lithium-ion batteries and employ 6,500 full-time workers in the Reno area.

This isn’t just about Tesla getting its own battery factory up and running, Bloombergnotes, but about proving to investors and customers that it can actually meet a deadline — after missing so many in the past — to introduce its first mass-produced car.

In order to get 500,000 Model 3 vehicles sold by 2018, Tesla has to make its own batteries because there aren’t enough of them made elsewhere to supply its own demand. It’s also much cheaper to make your own products at home.

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