The supercritical carbon dioxide (sCO2) power cycle operates in a manner similar to other turbine cycles, but it uses CO2 as the working fluid in the turbomachinery. The cycle is operated above the critical point of CO2 so that it does not change phases, but rather undergoes drastic density changes over small ranges of temperature and pressure. Supercritical CO2-based power cycles have shown the potential for increased heat-to-electricity conversion efficiencies, high power density, and simplicity of operation compared to existing steam-based power cycles. The sCO2 power cycle utilizes small turbomachinery, is fuel- and/or heat-source neutral, and efficient.
The Supercritical Carbon Dioxide Technology program goal is to develop highly efficient and lower cost indirectly-heated power cycles that surpass the performance of advanced ultra-supercritical steam and provide the technology base for directly-heated power cycles using more advanced fossil energy conversion systems based on sCO2 cycles. The direct-fired cycle can facilitate carbon capture by producing a high purity stream of carbon dioxide that is ready for use/reuse or storage. For a more detailed description of these cycles, see sCO2 Power Cycles for Fossil Energy.
The Fossil Energy (FE) Base Program work to develop sCO2 cycle components is funded by individual FE programs and is coordinated with the Supercritical Transformational Electric Power (STEP) program focused on the design, build, and operation of a 10 MWe pilot plant test facility.