Hydropneumatic energy storage
Suppose I own a wind turbine (or other energy source) and I want to be self-sufficient using only ecological means : the wind is not regular and my needs are concentrated on a few periods of the day: morning, noon and evening: I therefore need an energy storage system.
Whether at the individual or national level, we have to deal with peaks in consumption.
The system I propose uses only air and water: it is the same process as hydroelectric dams, except that it is not a question of producing MW but of kW and not requiring a river or a river, but to hold on a few square meters.
It is a hydropneumatic system: energy is stored in the form of water compressed by a mass of air, at a pressure of 150 bars (or 150 atmospheres).
A pump driven by the wind turbine or an electric motor compresses water in a large tank; the pump speed can be variable. The water is stored in one or more large steel tubes with a diameter of 600 mm, the same as those used for gas pipelines.
The energy is restored by a hydraulic motor driving an electric generator, storage and retrieval being completely independent.
This system thus only uses water for the transfer, as it already exists in industry (steel industry for example).
Calculations show that the yield is in the range of 75-77%, possibly better if all parameters are fine-tuned.
It takes about 1m3 of water to provide 1 kWh
All the necessary equipment exists, it is part of the recent developments (less than 10 years) of this “water hydraulics” technology.
Your opinions and observations?