Exergetic analysis and dynamic simulation of a solar-wind power plant with electricity storage and hydrogen generation

The ambitious vision of off-grid renewable energy autonomy of remote regions has yet to come to fruition. The development of comprehensive energy production systems would be needed to achieve such a goal. This study consists of the simulation and exergetic evaluation of a novel hybrid power plant for stand-alone operation aiming to provide electricity autonomy of a Mediterranean island. The considered power plant is simulated dynamically over an annual cycle and accounts for both energy input fluctuations and electricity surplus. The plant combines a photovoltaic array with wind turbines for energy input, coupled with electricity storage and a hydrogen generation facility to stabilize the power output of the plant. Unlike other similar studies, the energy system presented here relies on real-case weather and demand data of a relatively large remote community and is optimized to ensure continuous operation - even under extreme conditions. It is seen that this stand-alone hybrid power plant constitutes a robust and secure alternative to the current conventional energy situation; the combined renewable technologies succeed in complementing each other and offer stable performance throughout the year without the requirement of additional support by fossil fuels. The mean annual exergetic efficiency of the plant is found to be 17.9%, producing approximately 25,000 MWh of electricity per year, along with a secondary product (hydrogen) produced in the electrolyzer of the plant. Although this additional product is associated with additional investment cost, it offers the possibility to stabilize the power plant's performance and can be used as an additional source of financial income for the community.