Offshore power and hydrogen networks for Europe's North Sea

TL;DR

The paper analyzes Europe’s North Sea as an offshore wind and hydrogen hub under a carbon-neutral 2030 scenario using the open-source PyPSA-Eur model with high spatial and temporal resolution. It endogenously optimizes offshore wind deployment and the choice between meshed offshore grids and offshore hydrogen pathways, including wake losses and floating wind. Results indicate that a meshed offshore power network combined with offshore hydrogen yields the largest cost savings (up to ~€15 bn/yr) and can raise offshore wind capacity to ~420 GW, with floating wind up to ~75 GW when offshore hydrogen is present. Hallmarks of the findings are that offshore hydrogen becomes the dominant transport mode for offshore wind energy (about two-thirds) and that inter-country HVDC transmission remains a smaller share, with results robust to variations in onshore wind potential and transmission expansion.

Abstract

The European North Sea has a vast renewable energy potential and can be a powerhouse for Europe's energy transition. However, currently there is uncertainty about how much offshore wind energy can be integrated, whether offshore grids should be meshed and to what extent offshore hydrogen should play a role. To address these questions, we use the open-source energy system optimization model PyPSA-Eur to model a European carbon-neutral sector-coupled energy system in high spatial and temporal resolution. We let the model endogenously decide how much offshore wind is deployed and which infrastructure is used to integrate the offshore wind. We find that with point-to-point connections like we have today, 310 GW offshore wind can be integrated in the North Sea. However, if we allow meshed networks and hydrogen, we find that this can be raised to 420 GW with cost savings up to 15 billion euros per year. Furthermore, we only observe significant amounts of up to 75 GW of floating wind turbines in the North Sea if we have offshore hydrogen production. Generally, the model opts for offshore wind integration through a mix of both electricity and hydrogen infrastructure. However, the bulk of the offshore energy is transported as hydrogen, which is twice as much as the amount transported as electricity. Moreover, we find that the offshore power network is mainly used for offshore wind integration, with only a small portion used for inter-country transmission.

Figures (20)

• Figure 1: Schematic illustration of the different offshore connection types. The traditional point-to-point connection connecting the wind farm directly to shore, the hybrid interconnector connecting two countries while integrating wind energy and the meshed offshore grid connecting multiple countries and wind farms.
• Figure 2: Available area for offshore wind in the North Sea for water depths above and below 60 m.
• Figure 3: Location specific cost in the North Sea for a 12 MW fixed bottom wind turbines according to cost model from Danish Energy Agency. The wind turbine has a hub height of 136 m and a rotor diameter of 214 m.
• Figure 4: Possible transmission candidates of offshore grid in the North Sea. The topology is the same for the power grid and the hydrogen gird.
• Figure 5: Cost comparison of the four scenarios with their different offshore network topologies. The first column shows the reference case. In the other columns we calculate the cost differences compared to the reference case.