Subsea superconductors: The future of offshore renewable energy transmission?

The European Union has set the ambitious target of becoming climate-neutral by 2050 and reducing greenhouse gas emissions by at least 55% before 2030, compared to 1990. Greater energy generation can be achieved by increased reliance on renewable energy, but the transmission of this energy to match supply with demand is a likely bottleneck in maximising renewable energy use. In this paper, we examine medium-voltage DC superconductors as a potential solution for low-loss, high-power transmission of offshore renewables. We look at what has been achieved to date in onshore superconducting cable deployment and what needs to be done for such superconductors to be deployed subsea, with the goals of exporting electricity from offshore wind farms and acting as grid interconnectors. The offshore oil and gas industry represents state of the art in terms of subsea pipe design. This paper explores how the experience of the offshore oil and gas industry can be applied to subsea superconductor cable design and identifies aspects of superconductor design likely to present a challenge to subsea deployment. The key areas identified as requiring research are the development of flexible pipes suitable for cryogenic usage that can withstand the dynamic loading encountered in the marine environment; robust and low-maintenance insulation systems suitable for subsea deployment; and cooling systems to enable pipelines greater than 100 km in length. Although the primary focus of this research is on superconductor cables, the information is also applicable to other subsea conduits requiring cryogenic cooling such as ‘green’ hydrogen.