Decarbonisation pathways towards a net-zero North Sea energy system by 2050

The North Sea region, located in North-western Europe, is on the way to transform its energy system in the coming decades, with most of its surrounding countries having net-zero pledges in place. In this paper we evaluate different decarbonisation pathways towards a net-zero future by 2050 in the North Sea region, with a specific focus on the development of the offshore energy system. The proposed scenarios compare different mitigation strategies (i.e., intermediate targets versus a carbon budget), different marine spatial planning (i.e., development of multi-use of space areas in the North Sea versus single-use use of space) and different learning evolution of offshore technologies (i.e., quick reduction of offshore wind costs versus delayed reduction of offshore wind costs). Results show that distributing the carbon budget over the transition period is cost-optimal compared to defining decadal mitigation targets, providing 200 bn€ (3 %) lower system costs. Regarding the use of space, results show that a multi-use strategy provides savings of up to 100 bn€ (1.5 %), allowing the integration of over 350 GW of offshore wind and 1200 PJ of offshore hydrogen production per year. In terms of the learning rates of offshore technologies, the quick learning scenario, where fixed bottom offshore wind reaches a CAPEX of 1500 €/kW by 2050, entails 250 bn€ (3.75 %) less cumulative system costs than the baseline scenario, where the CAPEX of fixed bottom offshore wind reaches 2100 €/kW by 2050. In terms of use of space, the offshore wind deployment levels analysed in the modelled scenarios cover 5–8 % of all North Sea space, and 13–22 % of all the North Sea space not claimed by other activities.