The initiative started functioning after the opening of a heat recovery plant in December 2015, funded by the Finnish energy company Mäntsälän Sähkö OY, that extracts the data centre’s servers’ excess heat output and uses it to heat the district’s water. This method is substantially cheaper than building and operating a typical gas boiler, according to the company.

The project is anticipated to reduce heating costs for Mäntsälä citizens by 5% in the coming year and, according to Mäntsälän Sähkö OY, should cut utility providers’ gas consumption in half. The company claims that the project will also slash C02 emissions by 40%, corresponding with the EU target set for emission reductions in 2030. This energy collaboration with the city, allows Yandex to cut expenditure on the data centre’s current electricity consumption by as much as a third.

Water is fed from the city’s supply system into heat exchangers at the data centre where large ventilators pump in hot air generated by the servers. This hot air heats the water to 30-45 degrees centigrade, which is then sent to the heat recovery plant which boosts the temperature to the required level of 55-60 degrees. Once the process is complete, the water is transmitted back into the city network.

“We wanted to make full use of the excess energies we produce in order to benefit the community. For us it is important to give back to the community we work among,” says Ari Kurvi, data center manager at Yandex.

So far, only the data centre’s first stage is operational, with another three yet to go live. Based on the savings already being delivered from one stage of four, the company believes that once the entire data centre is operational, the city will be able to completely stop using gas to heat water and rely entirely on the data centre's heat.