Everything you do online, from checking Facebook to sending an email to reading this article, requires the use of data center. "The cloud," as BBC points out, "is a real place." And that place takes the form of millions of massive rooms and office buildings spread across the world, which house millions of servers.
These servers don't live in a vacuum. They use up massive amounts of energy, and give off C02 emissions and wasted heat. In the U.S. alone, nearly 12 million servers are housed in 3 million data centers, and they consume enough energy each year to power all of New York City's households for two years. That's the equivalent pollution of 34 coal-fueled power plants.
A huge portion of this energy use is air conditioning, which the centers keep on full blast to cool the machines and keep them running. So even though many data centers are going solar to combat their energy, there's still excess heat that could be used in a better way. In the Swedish capital Stockholm, they're using that heat to warm people's homes.
The way it works is Fortum Värme, the local heating and cooling agency, collects used water from the data centers. The water feeds through pipes at the centers, where it is used to create the cold air to cool the servers. The waste water is heated by this cooling process, so when it runs back out of the pipes and into Fortum’s plants, it's distributed across Stockholm's household to provide heat.
The project, called Stockholm Data Parks, is expected to generate enough heat to warm 2,500 residential apartments by 2018, but the long term goal is to meet 10 percent of the entire heating need of Stockholm by 2035, and then beyond. According to Data Centres By Sweden, which is launching similar projects across the country, only 10MW of energy is needed to heat 20,000 apartments. The typical Facebook data center uses 120MW.
Sweden isn’t alone in its quest to use data center energy to heat homes. Small-scale projects are underway in Finland, where one data center’s heat has been used to warm homes in a small city for a year. There are also programs in the U.S., Canada, and France, but Sweden’s move to scale it to this size across the country is a pioneering project.