Thermoeconomic modeling of a completely autonomous, zero-emission photovoltaic system with hydrogen storage for residential applications

In this study a completely autonomous, zero-emission photovoltaic (PV)-based system is modeled for residential applications. Apart from the PV subsystem, an electrolyzer-hydrogen storage-fuel cell subsystem is integrated to the system to fully fulfill a varying load profile throughout the year. The fuel cell and electrolyzer components are based on proton exchange membrane technology. The model allows quantification of energy and power flows, such as power input from the PV subsystem, conversion of electricity to hydrogen, and re-production of electricity. The system components are sized to satisfy demand, which is varied through a case study conducted to investigate system performance at different capacities. The economic performance of the proposed system is assessed with a detailed cost model. The proposed system (base case) results in a unit cost of electricity at 0.216 EUR/kWh for a system capacity of 100 households, which is moderately higher than the current cost of electricity in Cyprus. A parametric study including those economic parameters with a high degree of uncertainty is conducted to investigate the sensitivity and future potential of the system. The results show that the unit cost of electricity for the proposed system can be reduced below the current cost, making the system competitive, if electrolyzer/fuel cell lifetime is increased, while the specific costs of the electrolyzer and the PV are reduced.