Saving the Wind

April 1, 2010 | 2 Comments

Integrated Compressed Air Renewable Energy Systems (ICARES) research in development since early in 2006 is a technology centered on a simple premise – using giant wind turbines to compress and pump air into huge undersea Energy Bags™ anchored to the seabed – or geological formations where deep water is not available. The high-pressure air would be expanded in special turbo-generator sets to provide electricity as required – not just when the wind is blowing.  Designed to parameters fitting the local wind turbine atmospheric conditions, it’s a very good idea.

Energy Bag Lab Prototypes in Testing. Click image for more info.

Professor Seamus Garvey at the University of Nottingham, UK, is leading a new spin-off company, Nimrod Energy Ltd., aiming to prove that far from being just a pipe dream, the compressed air form of wind energy could be in widespread use within 15 years and at a fraction of the cost of its nearest competitor.

The undersea bags or geological formation stored high pressure air would be expanded into special turbo-generator sets to provide electricity as required – not just when the wind is blowing. The technology could become vast floating offshore ‘energy farms’ created off the coastline around the UK and many other places around the world.

Over the past year, Professor Garvey’s research has proven that by taking offshore wind turbines to a scale never before imagined – a 230 meter diameter model is the baby of the family – and considering some radical redesigns, the total amount of structural material per kW of rated power can be slashed, effectively cutting costs by a factor of four or more. He believes it is possible to store energy at costs well below £10,000/MWh – less than 20 per cent of pumped hydro energy (returning water back behind a dam), the cheapest competing technology.  The technology offers a full power energy saving to metered energy release system, something that levels the intermittent nature of wind.

The testing of scale-model prototype Energy Bags ™ has already commenced. A research project funded with €310,000 from the EON International Research Initiative has already funded the development of analysis and design tools for the energy bags and will provide further prototype testing in seawater leading to an energy storage product that will be ready for use in energy systems by May 2011.

Professor Garvey observes, “This is a classic case of a little foresight leading to technology becoming available exactly when the demand appears. The signals have been out there for years that offshore wind turbines need to grow much larger and that energy storage is going to become the key to integrating large amounts of renewable energy into the UK and world electrical power systems.”

And he astutely points out, “Moreover, the fact that wind turbine diameters were growing exponentially up to 2005 and then stopped fairly abruptly is a strong indication that conventional designs have come to the natural limit of size and that a major rethink is needed. While wind power contributes only a few percent of total UK electricity, we don’t really need to be able to store energy coming from the wind. By 2020, that will have changed profoundly for the UK – so much so that if we do not implement such storage in large measure, we will have to stop putting up wind turbines.”

The same issues apply in the U.S. as well, the intermittent wind supply has no cache or buffer to up rate its value to be either base load supply or as peak supply or to inventory the energy on hand.  Wind energy is currently available “when the wind blows,” hardly a way to extract the best rate of return or drive to a lowest cost for consumers.

Professor Garvey points out, “The UK has abundant offshore renewable energy resource – enough to supply all of our energy several times over. We also have a strong internal energy market – worth well over £60 billion per year. We have an economy desperately in need of rebooting its manufacturing base and an engineering capability, which is the finest in the world. Without an initiative like this, the UK will send vast amounts of money (several times £10 billion) abroad even before 2020 to buy offshore wind turbines and much manufacturing activity will go abroad with that. Worst of all, we will pay substantially higher prices for that equipment than we really need to and the UK energy consumer is going to feel that with sharp rises in unit energy costs over the next 10 years.”  The same basis is true for most developed national economies.

Justifiably enthused Professor Garvey said, “I believe that the ethical/green investment market is effectively waiting for precisely this company to appear. We have already demonstrated that the energy storage system can work. We have not yet built a 230 meter diameter turbine, but we know what it looks like. A neat mechanical engineering concept called ‘structural capacity’ shows directly and quantitatively why these new machines will be far more cost effective.”

At the end of this quote Professor Garvey gets to the major point, “I foresee that at least 25 per cent of offshore wind power in the UK will use this integrated compressed air approach by 2025. Although I expect that the direct-generating wind turbines will catch up with us on cost per unit power output, the role for systems that put energy directly into store is clear. If you have 1MW of integrated compressed air system (including the large energy stores) for every 3MW of conventional generation, then the whole set of offshore wind equipment starts to look like a very versatile power generating system which can adjust its output to match demand – notwithstanding what the wind is doing.”

Another point not discussed in the press release is the air being compressed to an under sea bag would have a linear compression and release pressure as determined by the depth in the water.  That is a major opportunity in capacity, reduced investment and operating expenses.  A store of compressed air is as readily available as opening a valve making the energy available from base load to peak or any point in between.


2 Comments so far

  1. Javier Moh on October 25, 2010 1:27 PM

    Very useful info. Thank you, I absolutely enjoy reading your post.

  2. wind energy on November 28, 2010 6:06 PM

    For sure, you need to keep working !

Name (required)

Email (required)


Speak your mind