Renewable Microgrids with PEMFC, Electrolyzers, Heat Pumps, Hydrogen and Heat Storages in Scenario-based Day-ahead Electrical Market

Microgrids enable the integration of renewable energy sources; however, managing electricity from intermittent wind and solar power remains a significant challenge. This study investigates two storage strategies for managing surplus renewable electricity in an IEEE 84-Bus microgrid with wind turbines and photovoltaic units. The first option involves producing hydrogen via electrolyzers, which is stored for later electricity generation through fuel cells. The second option involves converting surplus electricity into heat using heat pumps, which is then stored in thermal energy storage systems to efficiently meet the microgrid's thermal load requirements. A scenariobased day-ahead scheduling model is proposed to optimize the microgrid's electrical and thermal load management while considering uncertainties in market prices, wind speeds, and solar irradiance. The resulting large-scale optimization challenge is effectively tackled using the self-adaptive charge system search algorithm. The results indicate that, for the optimal utilization of excess renewable electricity, heat generation via heat pumps is more cost-effective than hydrogen production, primarily due to the inefficiencies in hydrogen conversion and the ability of heat pumps to produce several units of heat for each unit of electricity consumed. Moreover, heat pumps prove to be more economical than natural gas combustion in boilers for meeting the thermal demands across a wide range of gas prices. These findings highlight the economic benefits of integrating heat pumps and thermal energy storage systems into renewable energy microgrids.