Long-term power-to-gas potential for recovering excess energy from renewables: Italian case

Nowadays, electric grids experience issues due to renewable energy sources (RES) production variability. In perspective, RES share will continuously increase and potentially exceed the electric peak load, leading to a condition in which the utilization factor of RES plants is low due to production-demand mismatch. Electric energy storage (EES) has currently few options for large peak shaving (GWh scale); an alternative is production of hydrogen by water electrolysis (power-to-gas, P2G) for natural gas substitution (thermal purposes), as industrial feedstock or for mobility. In this work, an assessment of P2G potential in Italy is performed, considering long-term scenarios in which large share of RES leads to excess electricity. Historical time series from electrical transmission operator are rescaled in order to consider the evolution of load and installed RES capacity; hourly-based estimates of excess/lack of electric energy are calculated. This approach was already applied to Germany in other works [1] and results can be therefore compared.