This story was reproduced here as part of the Climate Desk collaboration.

On Tuesday, Apple CEO Tim Cook announced a massive new investment by the company in solar energy: an $850 million installation that will cover 1,300 acres in Monterey County, Calif. Apple is partnering with First Solar — the nation’s biggest utility-scale installer — on the project, which will produce enough power to supply 60,000 California homes, Cook said.

According to a press release from First Solar, Apple will receive 130 megawatts from the project under a 25-year deal, which the release describes as the largest such agreement ever.

Cook called it Apple’s “biggest, boldest and most ambitious” energy project to date, designed to offset the electricity needs of Apple’s new campus, the futuristic circular building designed by Norman Foster, and all of Apple’s California retail stores. “We know at Apple that climate change is real,” he said.

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Cook made the announcement during a Goldman Sachs technology conference, and First Solar’s stocks shot up Tuesday afternoon on the news:

Apple has already made huge commitments to solar. The Guardian reported last year that the company planned to use solar power to manufacture its new “sapphire” screens for the iPhone 6 at a factory in Arizona. Last year, Climate Desk joined the Guardian during a press visit to the biggest solar field then in Apple’s portfolio. The Maiden, N.C., facility has 55,000 solar panels that track the sun across a nearly 100-acre field, offsetting the electricity sucked up by Apple’s data center across the road:

Apple’s new investment continues the startling growth of solar in America, which my colleague Tim McDonnell has reported on previously: By 2016, solar is projected to be as cheap or cheaper than electricity from the conventional grid in every state except three. Over the past decade, the amount of solar power produced in the United States has grown 139,000 percent.

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In another portion of Cook’s appearance, the CEO boasted about the ways Apple’s new iWatch could help improve health by reminding you when you’ve become too sedentary:

Creepy, or cool?