Apple is doubling down on alternative energy at its new headquarters. In a updated environmental report, the company says the site will run entirely on solar energy and biogas fuel cells.

Where is all that energy coming from? The new campus will get 16 megawatts of power from rooftop solar panels, some of which will be affixed to the top of its two on-campus parking structures.

Parking structures on Apple's new campus. The one on the right features the solar panels. Apple

In addition to solar power, the new headquarters will be powered by 4 megawatts of energy from biogas fuel cells, which turn hydrogen and oxygen into electricity. Between the onsite solar panels and the fuel cells, it should be able to generate approximately 75% of the energy it needs during peak day time hours to run its campus, according to an Apple representative. The company will get its remaining power from First Solar, a California solar farm. In 2015, Apple struck a $848 million deal with First Solar for 130 megawatts of power, Bloomberg reported.

To run entirely on alternative energy, Apple has designed its own "microgrid," so that it can continue to run its facilities when local power grids go down.

The underside of the solar panels Apple

Why is Apple hunkering down on renewable energy? Climate change, according to the environmental report. The company has a stated goal of running all of its operations on renewable energy. According to the report, 93% of the electricity Apple uses worldwide already comes from renewable sources. Its efforts to go green have earned applause from former critics like Greenpeace. Last year the environmental organization awarded the company straight As on its clean report card.

But beyond changing the world, there's a financial opportunity here for the iPhone maker. The company says that for now, its goal is to generate enough energy to run its new headquarters.

However if Apple is able to generate a surplus of electricity, the company could one day start selling excess energy back to grid operators. Alternatively, Apple might be interested in leasing its microgrid technology to other companies. But it's likely going to be a while before Apple releases its plans. The new headquarters is slated to open in 2017.