Google recently announced it has now purchased 3 gigawatts of renewable energy capacity for the year, thus reaching its 2017 goal to go 100% renewable.
As Vox reports, this involved closing wind-power deals for around 400 megawatts in South Dakota and Iowa, and just under 140 megawatts in Oklahoma.
Google still relies on non-renewable energy to power its operations, but it has offset its non-renewable energy usage by buying the equivalent amount of renewable energy certificates (RECs), which are issued to wind farms or solar plants for each unit of electricity they generate. Plants sell the energy in normal markets and can sell the certificates separately to companies like Google, who by purchasing RECs, increase the profitability of renewable energy, therefore encouraging more renewable energy to be built.
A Bloomberg report from last year showed Google led the country in purchasing renewable energy, with Amazon in second place.
However, it is important to note Google is also a huge consumer of electricity, as it needs to power and cool its data centers. In 2015, Google consumed about as much energy as the entire city of San Francisco.