On September 8, Google announced that the company used 2.2 million megawatt hours of electricity and emitted 1.46 million metric tons of carbon dioxide in 2010. More than 1.2 million tons of that CO2 come from Google’s data centers, even though the company’s data centers use less than half the industry average. Google claims a “net zero” carbon footprint due to its purchase and generation of renewable energy, and the purchase of carbon footprint offsets. Fully a quarter of Google's energy came from renewable sources in 2010, which the company will increase to 35% by 2020.