Forecasting the integration of offshore renewables into the onshore energy system up to 2050

To meet the green transition targets, a significant increase in renewable energy in the electricity sector will be necessary in many countries, including Ireland – the case study for this work. Using the open source software H2RES, this research explores the roadmap to achieve 100% clean electricity for Ireland by 2050 through hourly-resolution energy system modelling under two scenarios: offshore wind alone (W) and offshore wind combined with solar (WS), representing different pathways for the integration of offshore renewables. On the demand side, hourly electricity power is predicted based on the available data while considering the role of demand-side units. On the supply side, the model accounts for unit commitments, along with energy storage and interconnections. All capacities are based on the current installed capacities, extended on the basis of short- and long-term projections. Subject to the constraints of electricity curtailment and CO₂ emissions, offshore renewable penetration levels are projected with the contribution of battery storage. All results come from cost optimisation while ensuring that energy balances are satisfied. By 2050, Scenario W projects 15.92 GW of offshore wind and 143.5 GWh of battery capacity. In contrast, Scenario WS, incorporating 12.79 GW of offshore solar capacity, reduces the offshore wind requirement to 12.11 GW and battery capacity to 76.8 GWh. This study provides valuable insights into the pathways for implementing offshore renewable energies in Ireland, offering guidance for global marine energy developments and advancing the UN's sustainable development goals for affordable and clean energy and climate action.