Hydrogen systems for large-scale photovoltaic plants: Simulation with forecast and real production data

• A model of a hydrogen storage system coupled to a 1.6 MWp PV plant is proposed.
• Real PV data and forecast data over a period of 14 days are used.
• Real data from electrolyzer and fuel cell manufacturers are used.
• The system injects a flat power curve in the grid to smooth unevenness of PV.
• Round-trip storage system efficiency is close to 40%.

The unevenness of solar photovoltaic energy output poses a number of issues that reduce its capability to be considered a reliable substitute for fossil fuels. For instance, solar photovoltaic plants convert and inject energy in the grid during the daytime, but fail to do so during bad weather conditions or at night. Variable weather conditions also render a reliable energy injection planning impossible, causing the photovoltaic power plant output to be most often unpredictable. Furthermore, all the energy converted and immediately injected in the grid poses the risk of creating imbalances in the electric energy distribution lines. A nation-wide energy system characterized by a large penetration of photovoltaic and wind energy sources can therefore be extremely difficult to manage and cannot be considered dependable. The core issue is how to improve the reliability of electricity production from such renewable energy sources.One way to tackle such unpredictability is to add an energy storage system. Many storage technologies are already available, although none of them has stood out to be the one and only answer to the problem. Different specific conditions require different storage technologies, and this is why that a combination of different solutions, rather than a single one, can be the right approach to storing energy.In this paper, a hydrogen energy storage system has been designed and simulated using real-life data taken from a PV plant of 1616.8 kWp successfully operating in central Italy. The aim is to understand the main operating conditions and the financial feasibility for infrastructure institutional investors to deploy hydrogen storage technology. The results show that such system is capable of guaranteeing a reliable energy injection in the grid, making the photovoltaic power plant as dependable as traditional fossil-fuel power plants.The advantages of such substitution are numerous: sizable decreases in green-house or toxic gases and pollutants, healthier environment, total energy independence from foreign energy fuel imports, local job creations, just to name a few.