Compressed air energy storage

by Milan on March 12, 2010

in Carbon capture and storage, Climate change, Power plants, Renewables

Carbon dioxide isn’t the only thing that might get injected underground in response to climate change. Wired is reporting on how storing compressed air could help utilities deal with the irregular output from renewable generation options, such as wind farms. When energy supply exceeds demand, these facilities would pump air into underground structures like salt domes. When the grid demands more power than renewable sources can supply, the high-pressure air can be released to regenerate electricity.

A facility in Alabama has been storing 19 million cubic feet of air at 1,100 pounds per square inch since 1991:

The plant’s output is 110 megawatts at full capacity, which is fairly typical of power plants now coming on line. It can run for 26 hours from a fully charged cavern and supply the demands of 11,000 homes, the institute says. Typically, however, it would run 10 hours a day or less, when demand is high. Another advantage, Mr. Meyer said, is that it can increase and decrease its power level quickly.

The facility can recover 870 watts from every 1,000 it stores – a higher proportion than is possible with either pumped hydroelectric storage or batteries. It also cost only $550 per kilowatt of capacity, compared with about $1,000 per kilowatt for pumped hydro. Despite those advantages, the Alabama facility remains the only one of its kind in the United States. A similar facility in Huntorf, Germany has been operating since 1978.

While air is an easier thing to store underground than CO2 (which forms acid in contact with water, and is riskier if suddenly released), it is conceivable that innovations in compressed air storage could be applied to carbon capture and storage operations, and vice versa.

Technologies and facilities like these will help to even out the peaks and troughs associated with renewable generation. Along with compressed air and pumped hydroelectric storage, promising energy storage options include pumped and multi-lagoon tidal facilities, as well as fleets of electric vehicles that can be charged when energy is ample and tapped as an energy reserve at times of maximum demand. Linking widely-separated generating sites using technologies like high voltage direct current (HVDC) transmission could also be an important way of dealing with fluctuations in output. When the sun isn’t shining in California or New Mexico, the wind may well be blowing in the Dakotas or along the Pacific Coast.

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Milan March 12, 2010 at 5:11 pm

All this goes to show, it can be smart to bury wind, too!

. March 12, 2010 at 5:15 pm

In the last four months, four projects have gotten new funding. In December, the rights to a long-awaited project in Norton, Ohio, were purchased by First Energy, a large utility in the area. The Norton project could store 2.7 gigawatts of power in an abandoned limestone mine.

In California, PG&E received a $24.9 million grant from the Energy Department to build a 300-megawatt plant in Kern County. New York State Electric and Gas received $29 million for a similar facility in the town of Reading, New York, using an existing salt cavern there. The Iowa Stored Energy Project received a $3.2 million forgivable loan from the state and will finish drilling its first research well in the next month. The plan is to attempt to store energy in porous sandstone, just like the 1.7 trillion cubic feet of natural gas that lie beneath the surface of the United States.”

. May 3, 2010 at 12:52 pm

“As well as aeroplanes, streamlined trains and slippery racing cars, anything from wind tunnels to jackhammers is stuff to be savoured. A special place in the pantheon of compressible air is reserved for the modern dentist’s drill. Those old enough to have suffered the drilling nightmares caused by that articulated contraption from dentistry’s dark ages, with its painful whirling of wire-belt drives, will know precisely why. Even closer to his heart, though, are those pneumatic hand tools that make DIY a pleasure instead of a chore.

For much of his adult life, your correspondent has wanted an air compressor for use at home. Unfortunately, he could neither afford one, nor could he find a place to house such a large, noisy, smelly, diesel-powered machine. Over the past couple of years, though, he’s noticed that air compressors have become ever cheaper and more powerful, thanks largely to the industrious Chinese. Better still, being electrically powered instead of relying on an internal-combustion engine, they can be used indoors.

You can now buy a perfectly adequate three-horsepower compressor that runs off a 120-volt household electricity supply for less than $180 (anything beefier needs a special 240-volt supply, like a washing machine). A half-inch impact wrench capable of loosening the rustiest of wheel nuts can be had for $80. A nailing gun for timber framing costs about the same; a paint gun around half as much. Air tools for cutting and nibbling thin sheets of metal are $20 or so.”

. September 1, 2010 at 5:39 pm

California Legislature passes energy storage bill

The California Legislature has passed the nation’s first energy storage bill, which could result in the state’s utilities being required to bank a portion of the electricity they generate.

Assembly Bill 2514 (AB 2514) now heads to the desk of Gov. Arnold Schwarzenegger (R), who has made climate change and green technology his political legacy as his final term winds down.

Energy storage is considered crucial for the mass deployment of wind farms, solar power plants, and other sources of intermittent renewable energy, as well to build out the smart grid.

PG&E, for instance, plans to build an experimental facility that would tap electricity generated during peak wind farm production to pump compressed air into an underground reservoir. When demand jumps, the reservoir would release the air to run electricity-generating turbines which are capable of producing 300 megawatts of power.

And last week, PG&E proposed building a “pumped hydro” storage system. As its name implies, the system would pump water from one reservoir to another reservoir at a higher elevation during times of peak renewable energy production. Water in the upper reservoir would then be sent back downhill to power a turbine when electricity demand begins to spike.

. December 15, 2011 at 9:20 pm

The DoE is also exploring another grid technology: superconducting magnetic energy storage (SMES). Because current flows unobstructed through a superconductor, once it is fed into one, it will continue flowing for a while without the need to expend energy to nudge it along. SMES systems could one day offer an alternative to lead-acid batteries as a way to store electricity and manage loads across smart grids. But existing SMES prototypes can only store energy for a few minutes at a time. ABB, a Swiss-Swedish conglomerate, has received $4.2m from the DoE to lead an effort to extend this to an hour.

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