An innovative turbine that is as small as a desk could provide enough power for an entire small town of about 10,000 homes. The turbine, which is being developed by GE Global Research, could be an excellent option for grid storage, because it is more efficient and flexible than conventional steam-based turbines.
The compact turbine uses carbon dioxide (CO2) at high pressures and temperatures, so that it exists in a fluid “supercritical” state that is between a liquid and a gas. The CO2 passes through the turbine, and is then cooled, repressurized, and sent back through the turbine again. Compared to steam turbines, the new one is more efficient because it has better heat-transfer properties and supercritical CO2 requires less compression than a steam-based turbine does.
It is a good candidate for on-demand power generation, such as during peak hours. Heat from solar energy, nuclear power, or combustion could first be stored as molten salt which could then be used right away, whenever a power boost is needed. The CO2 turbine only takes a couple of minutes to start working, whereas traditional turbines can take half an hour. It could even be a less expensive alternative to large arrays of batteries. Doug Hofer, the GE engineer in charge of the project told MIT Technology Review:
The key thing will come down to economics. At this point we think our economic story is favorable compared to batteries.