by David Talbot
a GE engineer in charge of the project,
shows off a model of the turbine.
as a strong rival to batteries
for storing power from the
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.
carbon dioxide (CO2)
passes through the turbine, it's cooled and then repressurized
before returning for another pass.
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.
Adding more hours of operation just means having a larger or hotter reservoir of the molten salt, rather than adding additional arrays of giant batteries.
While there's work ahead, he says,