Compressed-air storage coming to wind power

A New Jersey company said on Tuesday it will invest $20 million over three years to develop an underground compressed-air storage system for wind turbines and other power sources, a sign of growing confidence in the technology.

Energy Storage and Power is a joint ventured formed by energy developer PSEG Global and Michael Nakhamkin, who designed the only compressed air-storage facility in the U.S.

With Compressed Air Energy Storage (CAES), air is pumped into underground formations, such as depleted natural gas wells or salt caverns, using a natural gas-powered machine. The pressured air is released later to drive a turbine to make electricity.

A diagram of a compressed air storage facility. Click on the image to see a photo gallery of different grid energy storage technologies.

(Credit: CAES Development Company)

The system allows for several hours or even days of stored energy, which allows power producers to deliver electricity during peak hours when the demand for electricity--and price--is highest.

The two CAES plants in operation right now--one in McIntosh, Ala., and the other in Huntorf, Germany--use several hours of storage to generate electricity during the middle of the day.

Energy Storage and Power said that it intends to develop equipment for storing renewable power resources at a large scale. Utilities are already using more wind and solar, but energy storage means that they can be used more broadly since electricity can be "dispatched" as needed.

"We have learned a lot since building the McIntosh plant in Alabama, and I believe the time is right technically, environmentally, and economically for a large-scale deployment of Energy Storage and Power's CAES technology," Nakhamkin said in a statement.

It's not the only commercial company pursuing compressed-air storage of wind energy.

General Compression is designing a wind turbine that has a compressor built into the nacelle, the housing at the top of a wind turbine tower. The company hopes to test a machine with utilities in the next few years.

With the growing use of renewable energy on the power grid and a push toward energy efficiency, energy storage is getting serious attention from investors and utilities.

Lithium-ion battery company A123 is working with utility AES on grid-tied energy storage devices. These 1- or 2-megawatt devices can be used to stabilize the grid's frequency and store enough power for less than an hour.

One advantage of CAES technology is that it can be used for longer periods. The Iowa Stored Energy Park plans to use a natural gas compressor in conjunction with a wind farm that it expects to go online in 2011.

Updated at 12:51 p.m. PT with corrected reference to peak demand time.

[hongliuli]

why no one is thinking of utilizing gravity (using array of heavy objects) to store power? I have a plan (with animation demonstration), but do not know who should I send the idea to.

[k2dave]

They have thought of it. There has been many plans to pump water uphill to store it, then release it at other times to get back the power. Moving liquid is easier then a solid, and water is plentiful in some places.

[myrddin_1975]

"The system allows for several hours or even days of stored energy, which allows power producers to make electricity during off-peak hours when the demand for electricity--and price--is highest. "

I think you have the last part of that statement reversed. By definition, off-peak means that demand is less, and generally the price is less during off-peak as well. Yes?

[mlamonica]

Yes, you have it right. It was mixed. The idea is to store electricity (made at night) and release the stored air to make electricity during the day. thanks for spotting.

[open-mind]

One of the linked pictures describes a planned battery storage system with "a plan to buy 25 megawatts of storage". This makes no sense. Watts measure energy flow rate, not an amount of energy. It's like saying that "you plan to drive 25MPH of distance."

Should that be 25 megawatt-hours of storage?

[mlamonica]

In that case, iIt's 25 megawatts worth of capacity. See the press release from AEP in 2007: http://www.aep.com/newsroom/newsreleases/?id=1397

A battery could only discharge for a certain amount of time, though. So a one megawatt battery that can feed electricity for an hour can store one megawatt-hour. Here's another article on grid storage story with megawatts and kilowatt--hour measurements: http://news.cnet.com/8301-11128_3-9968539-54.html?tag=mncol

[gggg sssss]

I have a plan for a perpetual motion machine. But I can't reveal it to anyone. If Al Gore sees it he will steal it and call it his own. What to do?

[ssuccarl]

For more information about compressed air energy storage and its applicability to wind, see this recent report from princeton university: http://www.princeton.edu/~ssuccar/caesReport.html