In 2017 data centers in the U.S. alone used more than 90 billion kilowatt-hours of electricity, equal to the output of 34 power plants of 500 megawatts (MW) each. If all those plants were coal-fired, they’d have pumped out over 100 million tons of carbon dioxide - more than 2% of the CO2 produced by the entire U.S. economy in 2018. As demand for data centers picks up, so do the pressures – environmental, financial and regulatory – to develop them in a sustainable way.