More than a hundred years after the discovery of electricity by the great scientist Thomas Edison who illuminated the world, our lives have become heavily dependent on electricity generated by fossil fuels through our use of heating and cooling as well as the operation of many other electronics and devices.

What we see is that the use of this energy continues to increase, and this over time will become a dilemma and a place to focus on, since it is unsustainable energy. Here we have a number of questions, including where to meet this need?

So researchers have begun to produce other alternative means of generating electricity, for example, relying on renewable energy, where they created renewable energy networks that generate electricity by taking advantage of the power of nature (solar energy and wind), but because of climate change makes these innovations sometimes useless where the sun does not shine Always and the wind does not always blow.

Because of all this, all researchers shed their ideas to devise a way or another way to overcome this problem, where they turned to the technique of energy storage and reached several ways, including energy storage in the form of compressed air, where they started researching how they can benefit from this technology and can And will meet future energy needs.

The process of storing compressed air energy
Compressed air
The intermittent problem of renewable energy sources is one of the main problems that sometimes make it unreliable, and finding cheap and effective energy storage tools is one that will make renewable energy sources replace any other energy source.

There are currently energy storage devices such as batteries, for example, that store energy in the form of electricity, but according to current data, energy storage in the form of compressed air will be more effective when long-term storage is needed, ie seasonal storage, and this will change much in the reality of renewable energy technologies.

The concept of energy storage in the form of compressed air is the process of collecting air from the atmosphere by electric compressors and storing it with an appropriate mechanism in the form of compressed air (may be huge metal cylinders), and when energy is needed to take advantage of the stored air pressure to power generators.

For example, wind turbines will produce electricity or energy when the wind blows but may not be needed, so it is necessary to have tools in place to store this energy and ensure that it is not lost and used on demand, including the conversion of electricity energy into high-pressure air that will be used. Later to produce electricity.

In short, the transfer of energy outside peak times for periods when renewable energy networks need to be fed to function.

Where compressed air is stored
Compressed air can be stored in metal cylinders or underground water caves, which are a good way to store large amounts of compressed air that will replace unsafe drinking groundwater, as some of these caves store natural gas.

According to some researchers at the University of Edinburgh and Strathclyde, an important step in the process of storing energy in the form of compressed air is to identify the layers (saline aquifers) in which energy will be stored, so you should look for suitable geographical areas such as a rock or salt mine, and in Those layers will replace compressed air with some non-potable water, and this method is ideal for storing energy and is affordable.

The first compressed air storage plant in Germany was E.ON-kraftwerk’s 290MW to compensate for the shortage of electricity resources at peak times, ie as a backup power source, where two saline groundwater caves are filled within 8 hours and when needed, air is released and heated to power 320MW generating turbines. Electricity for two hours.

To increase the effectiveness of this method, focus should be placed on the retention and use of heat associated with pressure when heating the air.

During the search for underground rock caves close to the coast of the UK, researchers found that at least 77 to 96 terawatt hours of electricity can be stored in aquifers, this amount is sufficient to meet the maximum need for energy and increases.

Technical problems
Maintain high pressure
One of the most important issues to overcome for the success of this technique revolves around the pressure ratio when the compressed air comes out of the cave, where the pressure ratio is high if it is full and low if it is almost empty. There are two ways to maintain a fixed-size cave when compressed air is stored in it:

Allow pressure to change normally when air is released, which means that the turbine will generate less energy over time.
Controlling the flow of air coming out of the cave, which is released more at the end to meet the low pressure, ensuring that the electricity generated will be constant.
The second option is usually applied, where there is a constant amount of air driving the turbine.

 It is not a technology that works alone
It is a technique consisting of several other sub-techniques including compressors and heat exchangers, air storage design and thermal storage design. All of this requires careful engineering to get the right results.

 Not the ideal solution for short-term storage
Wind and solar power are still unavailable at all times and renewable energy networks store it for short periods.

But with the use of compressed air technology energy will be stored but this will be accompanied by high costs, and therefore is economical in the case of energy storage over long periods.

Temperature control
Heat is one of the factors that affect storage and conversion to electricity. To get the best return, a heat source should be provided when generating electricity to increase pressure and generate more electricity.

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