Investigating the value of csp in producing green hydrogen: study case hybrid pv-csp

Abstract

Having a steady supply of green H2 and heat has never been so important as industries e.g. steel and cement, are transitioning to greener production pathway. Hybridised solar photovoltaic–concentrating solar power (PV-CSP) systems are appealing to supply a nearly-continuous H2 and heat, due to the low upfront cost of PV, and cheap thermal energy storage (TES) of CSP. Few studies on the techno-economic assessment of H2 production from PV-CSP systems so far do not place great emphasis on the capacity factor (CF) of alternative system configurations, despite the major challenges of supplying H2 and heat to a continuously running industrial process. This study, which only considers supplying a cold H2, is a step toward that case and considers the use of a hybridised PV-CSP system, coupled with TES, supercritical CO2 cycle, resistive heater and alkaline electrolyser, to produce near-continuous H2. A multi-objective genetic algorithm (MOGA) optimisation to minimise LCOH2 and maximising capacity factor (CF) was conducted for PV and PV-CSP configuration. The result can be seen in Figure 1.

The lowest LCOH2 is 2.98 USD/kg for both systems at CF ~35%. The biggest difference in LCOH2 is at 0.51 USD/kg which occurs at CF ~80%. Both pareto fronts are converging at CF ~40% indicating the two optimisations converge at the same configuration where below CF 40%, CSP does not play any role. CSP starts to give benefit at CF > 40%. where PV-only system becomes expensive due to inefficiency in charging the TES.