APPLICATIONS OF TECHNOLOGY:

• Energy storage for intermittent renewable energy sources (wind, solar)
• Carbon sequestration

ADVANTAGES:

• Provides greater energy storage capacity than air alone
• Improves economic viability of renewable energy applications
• Provides value for depleted oil and natural gas reservoirs
• Potentially makes renewable energy projects carbon-neutral or net sinks

ABSTRACT:

Compressed Air Energy Storage (CAES) can make intermittent renewable energy options, such as wind and solar energy, more cost-effective by using excess energy generated during peak supply periods to compress air that is then injected into underground storage reservoirs. When needed, the compressed air can be fed into a gas turbine to replace between one-quarter and one-half of the natural gas needed to run the turbine.

CAES requires a cushion gas that compresses to store energy when air is injected into the reservoir and then expands to force out the compressed air during withdrawal. Air is typically used as a cushion gas, but a gas with greater compressibility yields more energy storage per unit volume.

Curtis M. Oldenburg of Berkeley Lab has developed a method of using CO2 as a cushion gas for CAES applications. CO2 offers far greater compressibility than air when it transitions from gaseous to supercritical form. Mixing between the CO2 cushion gas and the injected air is minimal because of CO2’s greater density and the significant viscosity difference between CO2 and air.

This invention can also be used for carbon sequestration whereby CO2 is injected into brine-filled formations, depleted oil or natural gas reservoirs, deep mines, or solution-mined cavities. As such, it offers the potential for obtaining carbon credits from cap-and-trade programs while providing functionality.

STATUS:

• Published Patent Application PCT/US2009/039281 available at www.wipo.int. Available for licensing or collaborative research.

To learn more about licensing a technology from LBNL see http://www.lbl.gov/Tech-Transfer/licensing/index.html.

FOR MORE INFORMATION:

Curtis M. Oldenburg, Carbon Dioxide as Cushion Gas for Natural Gas Storage, Energy and Fuels, 17, 240-246, (2003).

REFERENCE NUMBER: IB-2570

SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:

• Optical Sedimentation Recorder (OSR) for Tracking the Ocean’s Carbon Flux, IB-2196
• Tough +: Modeling Fluid and Heat Flow in Porous and Fractured Ground, CR-1275 and CR-2396
• Accurate Identification, Imaging and Monitoring of Fluid-Saturated Underground Reservoirs, IB-1663