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More Hot Air

October 31, 2014

When the EIA and AWEA calculate the cost of electricity produced by wind turbines, all the additional costs embodied in the production and transmission of electricity are ignored.

Because these costs are ignored, the LCOE (Levelized Cost of Electricity) from wind is purported to be nearly as low as the LCOE from coal and natural gas power plants.

It’s misleading to the point of being dishonest.

A good example of how costs are ignored is the proposal to build huge salt caverns in which to store compressed air that can be used to generate electricity using turbines.

The proposed storage installation will produce 60 MWh of electricity.

Once again, we are being driven to adopt an uneconomic proposal, at tax payer expense, because of a misguided fear of global warming.

The proposal to build salt caverns, compressor stations, turbine generators and a ten mile transmission line will cost $1.5 billion.

This cost should be added to the cost of generating electricity from the proposed wind farm, but it isn’t.

The wind farm alone, rated at 2,100 MW, without compressed air storage, will cost at least $4.2 billion, which is twice the cost of building natural gas combined cycle (NGCC) power plants rated 2,100 MW.

In addition, the NGCC power plants with a capacity factor of 85%, can produce 2.5 times as much electricity as the 2,100 MW wind farm that might, in Wyoming, have a capacity factor of 34%. The average capacity factor for land based wind farms is less than 30%.

The proposed system to produce electricity from wind, convert it to compressed air, then regenerate electricity from the compressed air, also wastes energy.

First, there will be an energy loss attributed to the compressors. At best, this will be a 10% loss for the compressor, but the compressor must be driven by an electric motor or gas turbine. If electricity is used, it will reduce the available electricity from the wind farm. If natural gas is used, it will consume energy and emit CO2.

Then there will be an energy loss when the compressed air is used in the turbine generators to generate electricity for transmission on the grid. Information on the type of turbine to be used is not available, so the amount of the loss can’t be established with certainty.

Only two compressed air energy storage (CAES) installations have been built thus far, one in Germany, the other in Alabama. The McIntosh CAES facility in Alabama, that went online in 1991, also incurs an energy loss when compressing the air. The compressed air is used as the air supply for natural gas peaking turbines, improving their efficiency, but still resulting in an overall energy loss.

Huntorf, Germany, CAES plant. Photo from DOE.

Huntorf, Germany, CAES plant. Photo from DOE.

The Huntorf CAES plant in Germany became operational in 1978, and essentially operates in the same manner as the McIntosh facility.

The sole reason for CAES is to compensate for wind energy being unreliable, because wind is intermittent.

Wind turbines either have to be backed up by gas turbines that can instantly replace the loss of electricity when the wind stops blowing, or have a method for storing the electricity produced by wind farms when it isn’t needed.

Batteries, pumped storage, fly wheels and CAES are different methods for storing energy that can be used to produce electricity, when its actually needed.

All storage is expensive and would increases the LCOE of electricity from wind if the costs were added to the cost of building the wind farms.

Wind energy advocates are intent on developing and building storage facilities, because it’s generally recognized that wind, combined with solar, can’t provide more than around 20% of the electricity on the grid.

Because of this, storage is becoming a big business with government subsidies. There is also an industry group, the Energy Storage Association, based in Washington, DC, that lobbies lawmakers and other groups in support of energy storage.

California, for example, is mandating that 33% of its electricity come from unreliable renewables by 2020, and has mandated that 1,300 MW of energy storage be built before then.

You’ll note that it is defined as MW rather than MWh, which makes the issue unclear as to how much storage is actually needed to allow the grid to function reliably when more than 20% of the electricity comes from wind and solar.

No matter what the requirement, storage is very expensive. None would be required if it weren’t that the government has mandated that wind and solar must be added to the grid.

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4 Comments leave one →
  1. October 31, 2014 9:39 am

    Thanks, Donn, for another informative column. I’ve plugged it into my “Electricity Storage” page:

    • October 31, 2014 9:44 am

      Great, thanks.
      I read your “Electricity Storage” page and it’s excellent.

  2. Bryan Leyland permalink
    October 31, 2014 9:29 pm

    Dear Donn,

    A very good article indeed. Well done.

    Regards, Bryan Leyland Phone 021 978 996


    • November 1, 2014 8:59 am

      Many thanks. Good to hear from you.

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