Technology

Storage of solar and wind energy, with the use of compressed air

Electricity produced from fossil fuels is becoming an increasingly unsustainable solution, so it is a one-way turn to renewable energy – mainly from the sun and the wind.

Renewable electricity generation is already less expensive per unit than equivalent minerals that are considered polluting to the atmosphere and harmful to the environment but the fact that the sun is not always shining and the wind does not always blow is an obstacle to energy sector.

Energy storage gives the opportunity to overcome this pressing issue. If storage was available at sufficiently low cost and high efficiency, the renewable energy source would immediately displace all other forms of production.

Storing solar and wind power using compressed air is really a very simple process, that is, all that is required is to collect air from the atmosphere, then compress it with electric compressors and then save the energy in the form of compressed air to a chamber. Afterwards, when you need this energy, you will let the air out, which will pass through a machine where it will take the energy out of the air and transfer it to the electric generator to be delivered immediately for use.

Compressed air energy storage (CAES) may include the storage of air in steel tanks or in much less expensive natural underground storage underground. In some cases, high air pressure can be stored in deep underground caves, either in rocks with hard rock or in large deposits of salt. These salt caves are often used to store natural gas.

Compressed air for the storage of renewable energy could well be used on a large scale because the cost is objectively much cheaper than the other methodologies, however for a strange reason it remains strongly underestimated by policy makers, funding bodies and the the energy industry itself. This has undermined the development of this technology and means that much more expensive and less effective solutions are likely to be adopted. At present, the three main problems hamper compressed air:

Compressed air energy storage lasts a lifetime

In most CAES systems, costs are concentrated on things that have a long life span. For example, a cave that works as a salt store can reasonably work well for at least 100 years, while high-power compressors and air-conveyors can typically operate for 50 or more years.

In short, it must be recognized by the responsible bodies that with such a long lifetime of these infrastructures, there is a strong incentive for all parties concerned to use this type of energy storage on a large scale. So if compressed air plants are treated as national infrastructure projects and funded by governments, then you understand that there will be a completely different approach to the energy we use.

In the past, two large compressed air units have been built decades ago, one in Huntorf, Germany and the other in McIntosh, Alabama. Both are still working very well. Many refer to these two factories to usually draw negative conclusions about how effective Compressed Air Energy Storage is and how much it may cost

But this is misleading and pointless.

Both plants were designed with very different priorities than those currently in place. It is imperative to rethink the storage of compressed air energy and to evaluate it properly in the light of what can be achieved by using modern methods and knowledge.