Innovative Industry Lead Project for Renewables for Subsea Power
Authors: Crossland Ian Roger , Slorach Paul , Caio Andrea , Parle Jay , McNatt Cameron 
Published: October 2022

The levels of power required to operate an offshore oil & gas field with 100% renewable energy are such that even offshore wind is unlikely to cost-effectively provide the levels of uptime needed to maintain reliable production without some form of energy storage. Providing a combination of technologies to maintain a balanced renewable energy supply system is key to reducing challenges with intermittency and to ensure consistency in supply and demand when called upon. This is true for localized assets offshore, as for large utility grids. Here we focus on the use of wave energy converters (WEC), in combination with energy storage, to deliver particular benefits when powering offshore assets in situ, especially when continuous power requirements are in the 10s-100kW range.

In 2020, a UK industry collaborative project called "Renewables for Subsea Power" (RSP) was launched and co-funded by the Net Zero Technology Centre (NZTC), formerly OGTC. RSP is a phased demonstration project involving three technology developers – Mocean Energy Limited, Verlume Limited, and Modus Limited – as well as a tier-one international services company (Baker Hughes) and a major North Sea operator (Harbour Energy, formerly Chrysaor). Given the focus on ramping up the energy transition, in 2022 another major North Sea operator (Serica Energy) and an autonomous resident vehicle supplier (Transmark Subsea AS), who replaced Modus Limited, also joined the project as part of the final phase (Phase 3) of activities.

RSP aims to develop a complete, fully-integrated system for the provision of low-carbon, remote power and communications using a WEC as the effective power source, a subsea energy storage system for power conditioning, smoothing and uninterruptable power delivery to subsea production control systems, and residential underwater vehicles for a variety of monitoring and/or maintenance activities. Throughout the three phases of RSP, project partners will design, build, and test all elements of the combined system. Phase 1 consisted in a front-end-engineering-design (FEED), which was successfully completed in 2021. Phase 2 involves the build and onshore commissioning of various subsystems and is ongoing due for completion in Q3 2022. Phase 3 will culminate in the offshore full-system deployment and trials during 2023.

Overall, RSP will demonstrate a complete, standalone, electrical and communication eco-system to provide power and communications for subsea infrastructure, moving away from the traditional transmission network approaches, such as a "Hub and Spoke", which typically rely on connecting subsea assets back to existing host facilities (e.g. platforms) using long umbilical cables. The phased approach discussed in this paper is used to highlight the key deliverables and activities, geared towards industry learning and, ultimately, adoption of a complete commercially viable solution upon Phase 3 concluding before the summer of 2023.

Figure 1 Renewables for Subsea Power (RSP) offshore equipment deployment plan