The speech not about exercises on the exercise bike for the sake of development of electricity, not about the dance floor generating electricity, and even not about the Matrix, and about experience of the Swedish company Jernhusen operating the central station of Stockholm. Here the system of heat exchangers where the water directed to heating at first is warmed up by the air deleted by ventilating system from the building of the station is realized. In the theory everything is simple: 200 thousand people of a daily traffic of the station breathe, drag suitcases and bags, hurry, sometimes swear. At the same time they allocate considerable amount of heat which still the system of ventilation just threw out on the street. Now, before release to winter Stockholm stuffy air is passed through system of heat exchangers where water circulates. It is known that temperature of the living person higher than 36,6 degrees are rare therefore to wait for boiled water at the exit from the heat exchanger you should not warm up, however, slightly cold water it is possible for further finishing temperature to necessary in the traditional ways. After heating water is pumped over in system of heating of the nearby business center which is also belonging to Jernhusen. In interview of BBC happy representatives of the company reported about 25% of economy on heating. Of course, for different territories this decision will have different efficiency which will depend on climate and the prices of traditional energy carriers.