Interested folks should check out the Allam cycle [1] and NET Power [2], which has successfully built and operated a carbon-dioxide turbine test facility and is now building a full-scale plant in Texas.
NET Power's approach has some significant differences from the DoE's. In their cyclical approach, natural gas and pure oxygen (obtained from an on-premises air separator) are combusted to form high-pressure CO2 and water. This mixture goes through a turboexpander, which generates electricity and lowers the pressure of the CO2-water mixture. After passing through a heat exchanger, the water is separated out as byproduct, and some amount of CO2 is also pumped out as byproduct. The remaining CO2 passes through the heat exchanger, brought back to high-pressure, and returns to the start of the cycle.
It's a quite incredible all-byproduct, no-emission energy generation process.
This doesn't seem to me that it's "no-emission" it reads more that it the co2 is captured at the source. As a lay person I would assume "no-emission" means no co2, but maybe I'm wrong here?
Not quite. According to the EPA [1], "Emissions is the term used to describe the gases and particles which are put into the air or emitted by various sources." That includes anything, not only CO2. For example, while CO2 is a common emission from fuel-based power plants, these plants (in particular, coal) may also emit other molecules such as mercury, which is more dangerous to human health than CO2. These all fall under the umbrella of emissions.
Even a hydrogen-fueled car has an emission of water, or a "waste product" [2]. And that's the key to understanding it: waste product, which is really what the term emission means.
What I talked about has virtually no waste product and therefore no emissions, though perhaps "no emissions" is too optimistic. The NET Power website says "NET Power’s patented technology captures over 97% of CO2 emissions from power generation", so it's darn good but not "no emission".
NET Power's approach has some significant differences from the DoE's. In their cyclical approach, natural gas and pure oxygen (obtained from an on-premises air separator) are combusted to form high-pressure CO2 and water. This mixture goes through a turboexpander, which generates electricity and lowers the pressure of the CO2-water mixture. After passing through a heat exchanger, the water is separated out as byproduct, and some amount of CO2 is also pumped out as byproduct. The remaining CO2 passes through the heat exchanger, brought back to high-pressure, and returns to the start of the cycle.
It's a quite incredible all-byproduct, no-emission energy generation process.
[1] https://en.wikipedia.org/wiki/Allam_power_cycle
[2] https://netpower.com/technology/