Controversial compressed air underwater cave energy project 

Posted: October 11, 2015 by oldbrew in Energy, innovation, wind

Offshore wind farm [image credit: Wikipedia]

Offshore wind farm [image credit: Wikipedia]

Is this part of the future for wind power, or just another doomed idea?

The search for new ways to produce energy are often complicated and controversial – and in Northern Ireland, a project to compress air into caverns under the seabed is no different.

It will be used, along with gas, to run turbines when the wind does not blow.

However some are worried that the process could be damaging to the natural habitat, as a short BBC video reports.

Well, it’s different if nothing else.

  1. A C Osborn says:

    Adding any kind of “storage” just adds extra cost.
    Go ahead Ireland make yourself even less competitive.

  2. oldbrew says:

    Wind project ends in court – 26 million euro row.

    ‘Bedrock damaged beyond possible remedial works’–nid2512.html

  3. michael hart says:

    Whatever it is, it’s not the future of wind power. How many wind farms have a convenient underwater cave nearby? Extra underwater engineering spending is required for what is probably a one-off project.

    It is ever thus with the most grandiose green schemes, R&D and manufacturing costs of building and engineering are treated as zero. By the same rationale we could build houses, hospitals, schools, and castles in the air for every man woman and child in the country, for no cost.

  4. Curious George says:

    Damages to the environment aside, how efficient an energy storage is it?

  5. A C Osborn says:

    michael hart says: ” By the same rationale we could build houses, hospitals, schools, and castles in the air for every man woman and child in the country, for no cost.”

    When it is not your money you are spending it is the equivalent of “Free” to them.

    Nothing is too expensive for the green boondoggle as long as it it the tax payer paying.

  6. oldbrew says:

    C George: up to 75% is claimed.

    ‘The overall efficiency of this system can be as much as 75%. Although 25%+ of the wind-generated electricity is lost, the remaining 75% is used at peak times thus reducing the number of conventional power stations needed to meet demand.’

    That’s the theory anyway. There are a few examples of compressed air storage with ‘normal’ power plants [link below].

    ‘The Future for CAES and Wind Power’

    ‘As more wind farms are constructed, and our dependence on the electricity they generate increases, energy storage is going to become more and more important. In North Dakota, the windiest state of the USA, Sirius Exploration plan to create eight 16m (diameter) x 160m caverns (by potash mining) which will be able to power a 100MW turbine when filled with compressed air. A similar project is being developed in Ireland by Gaelectric with a cavern large enough for at least a 136MW turbine.’

  7. oldbrew says:

    Car maker Peugeot blames government policies for ‘killing’ its compressed air hybrid tech.

    “Governments are fixing very ambitious targets in terms of CO2 – good news for the planet. That is their role and I strongly support that,” he [Peugeot CEO Maxime Picat] said. “Sometimes, too often in my personal opinion, they tell you what target to reach and what technology you have to push forward, which is nonsense.”

    Picat claims “Hybrid Air is a very efficient technology.”

    Air weighs a lot less than batteries obviously – even with the tech that holds in the air itself. And it’s free 🙂

  8. Steve Richards says:

    I have always been under the impression that compressed air operations are very inefficient and costly. Its ideal for a few engineering applications where its utility overcomes the lack of efficiency, but not many of those exist.

    This idea, could be good if we had no other option, no fossil fuel or nuclear, and we needed to a way to store energy for a few days. But all other alternatives are currently much better.

  9. Brett Keane says:

    Storage tends to lose the adiabatic ‘heat of compression’ energy. Bulk underground might minimise this, where available. A venturi check-valve, make and use as you go seemed most efficient when I was looking at it a few years ago. This utilises that heat-energy. Might be what Peugeot is using…

  10. stewgreen says:

    I came across it on July 19th and got the impression Gaelectric [toned down –mod]; making grandiose promises of £300m project to get €6.47m subsidy.
    I’d seen it in the EU subsidy list (€150m for energy infrastructure projects) and mentioned it on BH.
    – They’d had a project at one place in Larne, got a grant but then seemed to have ditched that location “We are now actively searching for sites in the Islandmagee area” (May 21st)
    I wonder if the site in the video is this oneidentified on August 19th ..That news story details the ocean concerns.

    – Wow BBC NI has dared run previous reports challenging green dogma ..In March : Cost of renewable energy subsidy on NI electricity bills ‘could treble’

    The critical guy in the video was from Marine Conservation Northern Ireland

  11. PeterF says:

    „Compressed Air Storage“ is one the storage technologies which had been considered here in Germany as savior of the (in)famous Energiewende. Since 2010 a consortium of industry and academia, lead by RWE (one of the big German electricity providers) and including General Electric was working on a feasibility study called „ADELE“ for adiabatic compressed air storage ( This has been halted in Sept 2014 for reasons of „not being economical“.

    There are obvious fundamental problems with this technology. When you compress air, the air gets hot, and you loose this heat to the environment (diabatic process). When you let the air expand through a turbine, you must heat the air e.g. with natural gas, or you freeze the turbine. Only two such facilities exist: one is in the German city Huntorf (, the other in McIntosh in the US (

    In order to generate 1 kWh of electricity you need natural gas in the amount of 1.6kWh (Huntorf) and 1.17kWh (McIntosh). A modern combined cycle plant would consume 1.67kWh of gas, i.e. over the life of a plant the compressed air likely has a negative energy balance over the CCP.

    In the adiabatic process you save the compression heat and store it in huge tanks filled basically with stones, and use it later to heat the expanding air (see pictures in above linked presentation).

    To store 10 days worth of electricity (for Germany), you ‘d need 17000 of those ADELE units, or 8 of them for every city of Germany. And they would cost 2000 billion € (Germany’s fiscal budget is 300 billion€).

    I am sure, for every offshore wind farm you will find not only the underwater cave, but also the place for the heat storage tanks :-/

  12. hunter says:

    There is no way that this is a positive energy balance. Wind > Electricity > Compressor > Storage > Plumbing > Turbine > Generator is far too many stages with far too many losses to make any sort of economic or engineering sense.
    Whoever is selling this should be investigated for fraud. Whoever is paying for it should fired for irresponsible lack of basic due diligence.