Compressed air system to save wind power for future use
As the demand for clean energy from renewable resources soar, implementation of technologies to save and maximize energy usage always remains the top priority. Given the situation of fast depletion of fossil fuels and environmental concerns, SustainX, a West Lebanon-based start-up has decided to use compressed air technology of storing wind energy generated by wind mills and producing the energy at peak hours. Air compression technology is not a new conception, but SustainX has come up with bigger plans to make it commercially viable.
The wind generated by the windmills can be compressed and stored in underground caverns or depleted oil fields, which can be released later to produce power when the demand is high. This will reduce the dependency on fossil fuels.
Storing of wind energy is a problem, but the necessity of storing this energy is ever increasing with the government imposing stringent rules in maximum power harnessing from renewable resources. SustainX has been successful in demonstrating a 40-Kilowatt prototype and is presently engaged in finishing a 1Megawatt project.
The biggest advantage of compressed air technology is that it can generate power from the stored wind energy even when the wind is not blowing. The compressed air can be released to rotate the turbine blades and dispatch power according to the demand. This concept of Compressed Air Energy Storage (CAES) has been lurking in the minds of engineers for few decades, but then technical difficulties and the cost proved to be great barriers. Presently, higher energy prices have created a situation to implement compressed air technology to cater to the demand of clean energy market.
Lack of enough storage space to store the compressed air for large scale power production is a big hindrance. SustainX has overcome this problem through the use of above the ground storage systems. The conventional turbine system does not work in above the ground storage tanks and SustainX has introduced pistons. These are cost effective and with better compression ability it can store more energy. Thus, above the ground storage tanks can store more energy than the same capacity underground caverns. Moreover, the pistons can function at a wider range when the tank pressure is too low to drive the turbines.
Air compression generates a lot of heat and decompression requires heat. Much of the heat generated during compression gets wasted. The efficiency of CAES can be increased if the heat generated during compression can be stored. SustainX introduced a fine water spray in the cylinder to absorb heat generated during compression and the same hot water is used as a fuel during decompression. No wastage of energy and no extra heat requirement. The energy efficiency has shot up from 54% to 95%. SustainX uses electricity to drive the pistons in the storage cylinders. During energy release, the decompressed air drives the piston to run a generator.
SustainX is working hard on isothermal compressed air technology due to its better energy efficiency. However, underground storage caverns are being considered more economically viable than above the ground storage tanks due to limited capacity of power production by the latter.