Professor Seamus Garvey is a Professor at Nottingham University’s School of Engineering and he has been championing the concept of electricity storage by using compressed air. Storing electricity is hard to do in an environmentally acceptable way.
Electricity demand and supply is intermittent. Electricity generated from renewable sources is also intermittent. We can store electricity in large batteries (they do this in Japan) or we can use mechanical means of storing it. The most well known of the mechanical means is to build a dam and pump water into it when electricity is over supplied and let the water out through turbines when electricity is needed.
Some scientists are looking at storing surplus electricity in electric car batteries, others are experimenting with flywheels, which might be another option, but Professor Garvey suggests that we can use compressed air as an electrical energy store and he has got backing from Eon to see if there is any commercial viability in his thinking.
The principles that the concept he espouses uses are very similar to those used in energy storage in dams. In time of over supply the surplus the surplus electricity would be used to compress air which would be stored. When we need the electricity the compressed air would pass through a turbine generating current which would be fed into the grid.
Professor Garvey proposes that the compressed air would be kept in vast undersea flexible storage bags, which would be anchored to the sea bed.
In the United States in Alabama and in Germany energy has been stored for many years using compressed air. In Alabama the storage is in underground salt mine caverns. In Iowa there is a project to use compressed air storage in under aquifers, 200 feet underground.
I suspect that there will be a number of matters which would have to be overcome if we are to see large scale storage through compressed air. The first is that when the air is decompressed it will cool; if it goes below freezing the ice may form on the turbine blades, which will hinder their efficient working.
The second issue is that compressing the air will use energy itself, so that the air compressed will probably provide “only” about 40% of the energy that it used before it was compressed. In my view this is no big deal because the energy would have been wasted anyway.
The third issue is the safety and viability of the storage sites, whether these are in underground mines, or underwater bags. Compressed air is tremendously powerful and needs careful handling.
If the technology can be developed into a commercially viable way of storing energy then there are tremendous benefits for the renewable industry. Of all the existing renewable ways of storing energy, only the heat technologies, and in particular solar thermal, can efficiently store the energy that they generate for use subsequently.
Wind energy is exciting and there has been a lot of investment in it but as the Renewable Energy Foundation points out, (http://www.ref.org.uk/Files/cd.euro.ceo.01.07.pdf ) there is not a great deal of reliable public data. It seems that on shore wind generation operates in the UK at around 20% of a turbines stated theoretical output, with the figure rising to 40% of off shore turbines. These are heavily subsidised by taxpayers’ money. We have yet to find out how much of that 20% or 40% is actually useful in grid terms.
Some American sources indicate that for every 1000 mW of wind power you need to have 900mW of fossil fuel back up, to cover the intermittency issue.
Professor Garvey wants to solve a very important problem – that of storing electricity. It has not yet been solved on a commercial scale. If he can solve it then although it will not see an end to fossil fuel generation it will mean that energy can be managed more efficiently, which will make renewables even more compelling and make the fossil fuel generating stations more efficient, bringing them closer to the efficiency of heat by solar thermal panels. The carbon dioxide savings would be immense.
Filed under: carbon emissions, climate change, electricity, energy, energy statistics, power, solar, solar energy, solar panels, wind turbines | Tagged: efficiency of renewables, freezing turbines, intermittent, Nottingham University, Renewable Energy Foundation, Seamus Garvey, surplus electrical storage
Hey guys… my professor gave me a task to find out a small generator which fuels on compressed air and generates electricity as the output… i searched all the internet but could not find anything….. if any of you guys know about this please let me know…. he gave me a hint saying one of this kind generator he found was in houston, texas, USA
Hey, can any one help me out.
i am planning to impliment a solar panel system for my house. For after sun hours i am thinking to compress air during day time by adding solar cells & then use a turbine that will run on this air.
even if the 40% is maintained, this is a great idea. The idea of having a natural battery is just fantastic. As for the 40% issue, if the system is being energized by renewable resources this is negligible to me. If these systems could become mainstream, the efficiency could be boosted by looking into improving the original harnessing of energy.
Ok, you have a designed solar system for your home to produce so much electricty. Why can’t you increase that production, by an amount to store air pressure for the use need after the sun goes down. You could build storage vessels into the walls, the attic, the basement, a tank in the back yard. Maybe build a small room. After the solar system is paid for (and now there are more incentives) the production is virtualy free, and your carbon footprint is much less. Then we can worry about a small business, then a big business, the grid etc, etc. Let’s start one house at a time.
Why isn’t there a federal grant in every land grant college in America for this.
I know of none; storing electricty is hard enough under normal conditions without having to capture the vey high current in lightening!
Robert
Lightningchild,
to store lighting has been a dream of mine for a long time. Is there any good info out there on this?