In Sweden's capital Stockholm, surfing the net is being turned into clean energy. How is that possible? A program there uses heat from data centers to warm homes. Pipes bring in cold water to cool things off, and then the warmed water is distributed to residences. Our reporter Xi Jia visited one of Stockholm's data centers.

Think that writing emails or online shopping can help warm a city in a cleaner way? Here in the Nordic city of Stockholm, people are getting heat from hundreds of thousands of computer servers.

The Stockholm Data Parks is a Government-backed initiative launched in cooperation with infrastructure companies. It offers space, power, networking and cooling as a service. The scheme enables data centre operators to sell their waste heat to the grid and then make a profit from that.

OSKAR PERENIUS HEAD OF DATA CENTER INSTALLATION BAHNHOF AB "The heat from the servers has returned to the heat bump, we then rise the temperature to 70 degrees for distribution into the public kit grid. On the other side of the heat bump, on the cool side we get about 79 degrees celsius in return to cool the data center."

XI JIA STOCKHOLM I am now in this information labyrinth. You can see rows of computer servers connected to each other and signal lights blinking all the time. You can feel the cool and dry air here. This is the place where the real "Cloud" is. So the next time you stream a TV show, you may be collecting heat for someone else on this planet.

Stockholm Data Parks are expecting to generate enough heat to warm 2,500 residential apartments by 2018. According to the Data Centres By Sweden, only 10 MW of energy is needed to heat 20,000 residential apartments. The typical Facebook data centre, for example, uses120 MW.

Cost turns into revenue when data centres become part of the city's ecosystem, and Stockholm has become one of the world's most popular places for big companies establishing their data centres.

ERIK RYLANDER HEAD OF OPEN DISTRICT HEATING AND STOCKHOLM DATA PARKS "The main reason is the low power price that we have in Sweden and also because there's been no tax for electricity for data centers in Sweden. Actually the tax for date centers electricity was cut by 98 percent in the beginning of 2017. Thirdly, I would say the energy you made in Sweden is very green. So it's sustainable and makes very low carbon emissions and that is also attractive to data center investors."

This kind of creation happens not only in Sweden. Countries like Finland, the US and Canada also have a similar system, but compared with Stockholm, their scales are much smaller. As an environmentally friendly, as well as a new business mode, many countries want to follow suit, but pre-conditions have to be met.

Nordic countries are leading the way in renewable energy, and they represent almost the fastest growth in the power industry. Replacing traditional ways with sustainable practices is not only environmentally responsible, but intelligent business practice. Xi Jia, CCTV, Stockholm.