The U.S. Department of Energy hopes to create a more efficient turbine that uses CO2 to make electricity
A simpler, smaller, cleaner machine
The term "supercritical" describes the state of carbon dioxide above its critical temperature and pressure, 31 degrees Celsius and 73 atmospheres. Under these conditions, carbon dioxide has a density similar to its liquid state and fills containers the way it would as a gas.
Supercritical turbines would also be an attractive upgrade from steam systems aboard ships and submarines, producing the same power while occupying less space. Because they use carbon dioxide instead of water as their process fluid, these turbines would also work well in drought-stricken areas.
In addition, a supercritical turbine could fit into a directly heated cycle, where a fuel like natural gas burns in the presence of pure oxygen inside the turbine, creating only water and carbon dioxide as waste.