The fuel cells take methane -- in this case, produced by animal waste -- and convert that to electricity. Apple's installation will be built by California's Bloom Energy, and it will be the largest such fuel cell installation built outside of the utility industry, the News & Record reports. The first of Apple's fuel cells could be online as early as June, and Apple expects to have the whole facility up and running by the end of November. Apple isn't saying publicly what it will cost -- that part was filed under seal. Apple's trying to turn around its reputation as a dirty energy user with the Maiden facility, which powers its iCloud. Right next to the biogas plant, Apple's building a massive 20-megawatt solar array.