Zero-Emission Natural Gas Plant Fires Up

zero emission power plant.jpg

 

NET Power designed a plant the produces low-cost electricity from natural gas that generates a near-zero atmospheric emissions with a full CO2 capture.  It is called a supercritical carbon dioxide (sCO2) plant.  According to WIRED, turbine generators that utilize supercritical  CO2 (extremely hot and compressed CO2) could generate more power with smaller turbines than the steam turbines most plants currently use.



More than two thirds of all the electricity in the US is generated using steam generators operating on what engineers call the Rankine cycle. You start with water, pressurized using a pump. Then apply heat—by burning coal, letting radioactive material decay, or focusing sunlight reflected off thousands of mirrors onto a single point. This boils the water, creating steam. Add more heat. And still more heat. You want that steam as hot as possible before sending it through the turbine: More heat means more energy means more electricity. The turbine blades spin, and the generator attached to them creates electricity. Then steam goes through a condenser, becomes water, and returns to the pump. The cycle begins anew.
— Wired

The supercritical CO2 option skips the liquid phase.  It stays (mostly) gas throughout the process, making it more efficient.  The CO2 gets semi-liquid, allowing it to push through a turbine 10x faster than a standard steam turbine.    



 

NET Power is using the Allam Cycle, which burns natural gas with oxygen, and uses high-pressure sCO2 as a fluid in a semi-closed loop to run the combustion turbine.  The byproducts are liquid water, CO2, argon, and nitrogen, which can all be sold as commodities.

Is the supercritical CO2 molecule the future of power?