Underground air energy storage may be possible solution to high energy costs

July 5th, 2008 - 3:01 pm ICT by ANI  

Washington, July 5 (ANI): Scientists have suggested that a possible solution to high energy costs could lie underground in the form of compressed air energy storage (CAES).

Sandia National Laboratories researchers Georgianne Peek and Steve Bauer have put this idea forward.

Until recently energy has been relatively inexpensive. But now prices are rising dramatically, and we need solutions, said Peek. CAES and other storage technologies are not the only answer to our energy needs, but they can be an important part of the solution, he said.

CAES facilities function like big batteries.

Electric motors drive compressors that compress air into an underground geologic formation during off-peak electric use times like evenings and weekends.

Then, when electricity is needed most during high-demand times, the precompressed air is used in modified combustion turbines to generate electricity.

Natural gas or other fossil fuels are still required to run the turbines, but the process is more efficient. This method uses up to 50 percent less natural gas than standard electricity production.

While the concept of compressed air energy storage is more than 30 years old, only two such plants exist a 17-year-old facility in McIntosh, Alabama, located about 40 miles north of Mobile, and a 30-year-old plant in Germany, both in caverns in salt domes.

A third is being developed near Des Moines, Iowa, in an aquifer.

Sandia is currently managing DOE (Dept. of Energy) money to support the design of the Iowa facility, called the Iowa Stored Energy Park (ISEP).

ISEP will be a nominal 268 megawatt/13,400 megawatts per hour CAES plant with about 50 hours of storage. It will utilize the abundant wind generation already in Iowa to charge the plant.

When ISEP is up and running, it could account for 20 percent of the energy used in a year at a typical municipal Iowa utility and could save cities and their utilities as much as 5 million dollars each year in purchased energy.

This summer, multiple core samples from the potential Iowa aquifer CAES site will be taken and sent to Sandia for analysis by a team led by Steve Bauer. The analysis will include collection and assessment of the geologic, hydrologic, and rock physics data in the geomechanics laboratory.

The data will provide necessary fundamental information used for the design and performance of the underground air storage vessel.

Storage enables delivery of the off-peak energy that has been saved in storage to be delivered when it is needed most or has the highest value. Thus, more renewable energy can be delivered than might be possible without storage, said Peek. (ANI)

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