Science & Technology: Supercritical Carbon Dioxide Turbine Could Generate 33 MW

Desk-Size Turbine Could Power a Town (MIT Technology Review)

Doug Hofer, a GE engineer in charge of the project,
shows off a model of the turbine.

GE Global Research is testing a desk-size turbine that could power a small town of about 10,000 homes. The unit is driven by “supercritical carbon dioxide,” which is in a state that at very high pressure and up to 700 °C exists as neither a liquid nor a gas. After the carbon dioxide passes through the turbine, it's cooled and then repressurized before returning for another pass.

The unit’s compact size and ability to turn on and off rapidly could make it useful in grid storage. It’s about one-tenth the size of a steam turbine of comparable output, and has the potential to be 50 percent efficient at turning heat into electricity. Steam-based systems are typically in the mid-40 percent range; the improvement is achieved because of the better heat-transfer properties and reduced need for compression in a system that uses supercritical carbon dioxide compared to one that uses steam. The GE prototype is 10 megawatts, but the company hopes to scale it to 33 megawatts.

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