Solar and wind power is developing rapidly, and new stations are put into operation around the world. The increase in the volumes of energy produced by alternative sources makes the issue of accumulation and conservation of energy more urgent.
Even literally a few years ago, reservoirs were consider one of the most reliable energy storage, especially for its large volumes. Specially designed reservoirs for storing large water reserves. Subsequently, water is use to generate electricity. This method proved to be a costly material; moreover, such an energy store occupies a large area.
Groups of scientists around the world have been working on the creation of new storage facilities for the first time, but it has not yet been possible to create a capacious and not too expensive storage facility. The energy accumulated from the sun, wind, other «green» sources should be stored in large volumes, and at the same time, the storage should not take up too much space to be conveniently located near large cities.
Scientists from the UK have solved this problem with the help of liquefied air. The development of the new project involved employees of the company Highview Power Storage. The essence of their invention is that the surplus generated electricity is use to reduce the air temperature to -190 degrees Celsius. This gives an energy carrier in a concentrated form, which in scientific circles is call cryogen. Liquefied air is stored with a special tank and a pressure of one bar.
This project was call LAES (storage of energy of air in liquid form or cryogenic energy). The power storage has a number of advantages, unlike batteries and devices using water-pumping technologies.
The technology proposed by British scientists involves the use of electricity to reduce the air temperature, which subsequently liquefies. The cryogen storage tanks are isolated from each other, but they are not close tightly. If necessary, the system injects liquefied air into the cavity of the heat exchanger. There, the cryogen is heated (the temperature should correspond to the ambient conditions) at a pressure of 70 bar. Thanks to this procedure, the liquefied air again becomes gaseous. The re-gasification process triggers a turbine generating electricity. The cooled air that remains or dissipates during this process does not volatilize. He is catch by special equipment for further use in liquefying air again.
Scientists say that heating the liquefied air to ambient temperature compensates up to 50 percent of the energy costs from the procedure itself. If the cryogen temperature is increase further, the energy cost compensation index will increase to 75 percent. For heating, the utilization of excess heat energy of production can be use.
The British cryogenic power storage has passed all the necessary tests and is already putting into operation. For example, not far from Manchester, a five-megawatt cryogenic installation is operating successfully today. In addition, the storage tanks were install at a power plant generating electricity from biomass in the town of Slough.
The company Highview Power Storage proclaims that it plans to increase the capacity of its accumulating plants over time. At this stage, cryogenic energy storage facilities have a capacity of 3.5 megawatts. Representatives of the manufacturer intend to increase this figure to a level of 8 or even 10 megawatts. In addition, the company’s plans for the current year include the construction of four large air diluters, two tanks for liquid air, containing 7.7 thousand tons and playing the role of a battery, eight turbines of 25 megawatts each.
Cryogenic storage does not involve the use of toxic or rare compounds. For energy storage facilities of this kind, no special geographic conditions are required (a separate large area, as in the case of pump hydroelectric power). LAES does not require huge financial costs like other battery systems. Cryogenic installations can be integrated absolutely into any solar or wind station.