As more of our lives move online, power-hungry data centers are multiplying. Already, the servers that run weather models, fuel financial markets, and store Facebook statuses soak up about 1% of the world’s electricity. By the end of the decade, they could use as much as 20%.
A big chunk of that power—about 40%—goes toward keeping the machines cool. Operators spend billions of dollars (and billions of gallons of water) each year on cooling systems that shed heat from the computers into the atmosphere.
There’s a better use for that all wasted heat: heating homes and businesses that would otherwise burn gobs of fossil fuels. For the past decade, researchers have called on cities to close the loop and recycle waste heat from server farms to cut costs and carbon emissions.
Some towns listened. In 2010, Helsinki installed a massive data center in a disused bomb shelter and piped enough hot water into the city’s district heating system to warm 1,000 apartments. That year, Parisian computer servers began heating a nearby arboretum. The Winnipeg Sun began using heat from a downstairs data center to warm its offices in 2011.
So far the idea has been slow to catch on, as falling fuel prices and logistical barriers have crimped the economic incentive to reuse waste heat. But renewed corporate commitments to sustainability and imaginative efforts to bring servers directly into the buildings that need to be heated could hasten adoption.