The role of hydrogen storage and electric vehicles in grid-isolated hybrid energy system with high penetration of renewable

A techno-economic optimization for an isolated grid with a high share of renewables (75%) is presented, with the goal of providing an energy-balanced system at low-cost and reducing stresses on the distribution network. The model, developed with TRNSYS software, involves a wide variety of renewable generators and storage systems. Special attention is given to the possible synergy between electric vehicles, including their use as grid storage, and hydrogen as an energy carrier. Two locations with different climatic conditions (cold continental and southern Europe) were considered to study the influence of resource availability on the resulting energy mix. The main impact of electric vehicles is due to the emergency charging, which increases peak demand by 50%. Nonprogrammable renewables have the lowest cost, but require expensive storage to balance the grid. In continental climate (Northern Italy), hydro can provide near-base load generation, minimizing the need for storage and achieving a minimum LCOE of 0.1464 USD/kWh. The good solar energy at a low latitude location (Southern Italy) allows the CSP system to be exploited where the integrated thermal storage reduces the demand for highcost electric storage: the best solution achieves an LCOE of 0.1890 USD/kWh, comparable to the cost of the Italian market.