System for storing energy by means of compressed air

Abstract

A plant for storing energy by means of compressed air, in which: a storage volume accommodates air at elevated pressure pH; for energy storage, ambient air is compressed and introduced into the storage volume; for removal from storage, compressed air is extracted from the storage volume and discharged into the environment, performing work; at least one low-pressure turbomachine for alternate compression and expansion respectively compresses ambient air to a medium pressure pM and expands said ambient air from said pressure; at least one high-pressure machine for alternate compression and expansion respectively compresses air from the medium pressure pM to the store pressure pH and expands said air from the latter pressure; and said low-pressure turbomachine and high-pressure machine are connected in series in terms of flow and are mechanically coupled to in each case one, or to one common, electric machine that operates selectively as a motor and generator.

Description

Technical field [0001] The invention relates to a facility for storing energy by means of compressed air. Background technique [0002] Fossil energy should (because of carbon dioxide) be replaced by renewable energy. The difficulty in power supply lies in the fact that the supply of renewable energy, such as the use of wind energy through windmills and the use of solar energy through photovoltaic technology, fluctuates sharply, and the demand for electrical energy can only be used as widely as possible when the electricity generated by renewable energy can be stored. Regenerative energy meets demand. Known methods for this are: batteries-apparently too expensive at the moment; pumped storage power plants-for this purpose, large height differences are required and these large height differences do not exist, for example, in the lowlands of northern Germany. In addition, People often protest because of "destroying the scenery"; or compressed air energy storage facilities (usuall...

AI Technical Summary

Problems solved by technology

[0010] In the mentioned DE 10 2007 042 837 A1, a high-pressure compressor specially designed for alternating pressure and also such a steam turbine alleviates the problem, another solution is the speed regulation of the turbine, so as to be compatible with the speed adjustable in pumped storage power plants The approach in the pump-turbine similarly approximates the congruence of the velocity triangle and thus keeps the efficiency loss low, but has the disadvantage of the cost of expensive power electronics in the megawatt scale and can only provide with difficulty the support for the so-called short circuit current demand

[0011] In a turbine-only solution it is difficult to achieve high pressures for proper utilization of the storage volume, especially when the facility is less than 50 MW

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