As usual for a press release this is more hype than insight but it looks like they are doing three things here:<p>- Burning natgas<p>- Capturing all CO2 from the combustion process<p>- Using supercritical CO2 in the power turbines in place of (water)steam<p>Honestly it's the last part that has my attention. Most heat->(water)steam->turbine systems have a maximum 33% efficiency. NREL has been working with supercritical CO2 for quite a while because it gets well over 40%, possibly as high as 50% efficiency. In part it's because there's not a phase transfer taking place like in a normal water-steam turbine system so the cooled CO2 after the high pressure and low pressure turbines requires less energy to be re-heated. Also, at super-critical state the CO2 behaves more like a fluid than a gas and has greater "horsepower" (for lack of a better term). Either I'm behind on the supercritical CO2 news cycle or this is the first time they are making it work at near-utility scale. The goal for a long time has been to get this to work at the 600MW+ power stations (be it coal, natural gas, or any other sufficiently hot heat source) as the jump in thermal-to-electrical efficiency would be massive.