Solar plants cut costs 42% by swapping steam for CO2 power cycles
Researchers found that replacing traditional steam turbines with supercritical CO2 systems in solar thermal plants slashes electricity costs dramatically—and pairing these plants with rooftop solar cuts costs another 22%. The breakthrough matters because it makes concentrated solar competitive in smaller markets and cloudier regions where it previously failed economically.
Originaltitel: Techno-economic optimization of molten salt based CSP plants through integration of supercritical CO<sub>2</sub> cycles and hybridization with PV and electric heaters
<p>The present study explores the integration of supercritical CO<sub>2</sub> (sCO<sub>2</sub>) power cycles into Concentrating Solar Power (CSP) plants using molten salt, and the hybridization of these plants with solar photovoltaic (PV) systems through electric heaters. Techno-economic evaluations determined the optimal power cycle configuration and subsystem designs for two different scales and locations and then compared them with state-of-the-art solar power plants. The results show that hybridizing PV with state-of-the-art CSP can lead up to a 22% reduction in the Levelized Cost of Electricity (LCOE) compared to standalone CSP systems. This hybridization and the use of electric heaters are particularly beneficial for small-scale installations and locations with low DNI/GHI ratios. By replacing the steam Rankine cycle with a sCO<sub>2</sub> power block, a further 42% reduction in LCOE can be achieved at small scales, even with a simple recuperated cycle. In conclusion, the hybridization with PV and the integration of sCO<sub>2</sub> power blocks provide cost benefits despite the temperature limitations imposed by the molten salt. Hybrid PV-CSP plants with sCO<sub>2</sub> power blocks prove to be a cost-effective solution for capacity factors exceeding 60%. For lower capacity factors, configurations combining PV with battery energy storage or PV with electric heaters, thermal energy storage, and sCO<sub>2</sub> power blocks are preferable options.</p>