Iowa project tests wind power’s weaknesses
A $400 million project in Iowa is geared toward addressing two of wind power’s drawbacks: energy storage and variability. The Iowa Stored Energy Park would use an underground aquifer near Dallas Center, Iowa, to store air produced by wind and then, during peak hours of demand, the stored air would be released, combined with a fuel and used to power two combustion turbines that would produce electricity.
The project began eight years ago by the Iowa Association of Municipal Utilities (IAMU), which represents more than 550 municipal electric, gas, water and telecommunications utilities statewide. “The wind blows night and day, but it’s not always consistent. That’s why we need to store it,” says the project’s Development Director Kent Holst.
The Iowa project is an adaptation of the same technology that is commonly used to store compressed natural gas, Holst says. There are only two other similar wind storage facilities in the world: one in McIntosh, Ala., and the other in Huntorf, Germany. Those facilities use underground salt domes to store air.
If successful, the project would generate enough electricity to power 75,000 homes at a time. The storage project seems viable to project designers because it combines “three known technologies — storage of gases in aquifers, simple-cycle gas turbines and wind energy,” says IAMU Executive Director Bob Haug. It also uses wind generators that are being built in Iowa, which is now second to Texas [in total wind generation capacity]. Storage of off-peak energy provides the possibility to make wind turbines a dispatchable resource, Haug says.
The project is funded by grants from the state and the U.S. Department of Energy, and is a joint effort with other municipal utilities from North Dakota, South Dakota and Minnesota. Holst says they are currently testing the walls of the aquifer to be sure they are strong enough to hold the air, which would be contained in a facility he described as an “upside down bowl.” “We’re drilling into the aquifer to get core samples so we can make sure the permeability, velocity and chemistry is what we need,” Holst says. Once testing and construction are complete, Holst estimates the storage project could be online in 2014 or 2015.
Read more information on the Iowa Stored Energy Park.