Under the hood, Facebook — the sixth most visited website, according to Alexa — is basically a bunch of data centers. Those data centers use up loads of energy, consuming up to 50 times the energy of a typical commercial office building of the same size, the US Department of Energy says. In fact, they account for more than 95% of the energy that Facebook consumes. Urvi Parekh’s job is to make sure the energy they use is clean.