Green power: pressurising air underwater

I'm all for green power but the problem is with fluctuating supply, as with wind or solar. Supply rarely marches demand, so being able to cheaply and simply store power is vital. Batteries has been the usual approach when studying the problem, though pumping water uphill when there is little demand (and running it out through turbines) has its fans as well. The UK has been using this concept for decades.

Seamus Garvey, Professor of Dynamics at the University of Nottingham, has come up with a solution to the problem: when wind power isn't needed, it's stored in canvas bags under pressure in the sea.

I came across the idea in the article "Bottling the wind" by Abigail Beall in the 1 November New Scientist issue. She explains that the mechanical engineer was driving on a motorway when he thought of the idea of storing unwanted power underwater. When the power was needed, it would become available again, as simply venting it would drive a generator.

He tried to prove it was a bad idea and then realised it was a very good idea. If you want to store compressed air you need a lot of pressure, and there is no lack of that deep in the sea. Garvey was quoted as saying "It's important to take advantage of the stuff around you".

What about the patents ? As long ago as 2007 a World patent application in his name was published, with the University of Nottingham as the applicant, titled Power generation. Here are two patent drawings from the (American) patent specification.

The corresponding European patent application is still, all these years on, undergoing examination and has not therefore been granted protection. The European Register entry EP1971773 lists the various actions and by clicking on All Documents, at top left of that page, the correspondence with the European Patent Office can be read. Maybe the 10 patent documents cited against the World application were causing a problem. Meanwhile, in 2011 US8030793 was published.

At the time of writing, 16 patents since 2007 have had the Garvey specification cited against them, and are listed here. Clearly, there is interest in the topic.

There are a lot of videos about the concept or Garvey available. Garvey is now working on a commercial system with Canadian wind power company Hydro-Star Energy, LLC.