Integrated approach offshore could save billions


An integrated approach to offshore wind could save consumers £6bn and substantially reduce the amount of cables that have to be laid, National Grid ESO has found.

The report, published in late September, falls under both the government’s wider offshore transmission network review which was launched this summer and National Grid’s own Offshore Coordination project. The latter, ESO explained, is setting out to deliver a number of reports on the strategy for connecting offshore windfarms to Britain.

In July, the government announced a review into the existing offshore transmission regime and that Ofgem would examine the idea of an offshore ring main (ORM). In light of Vattenfall’s plans for the Boreas and Norfolk Vanguard offshore windfarms, as well as Orsted’s plans for Hornsea Three, it is hoped that something like an ORM would mean that separate cable corridors and onshore substations would not have to be dug across the countryside to link each new windfarm to the grid. The idea of an ORM has the backing of Mid Norfolk MP, George Freeman, who supported a petition launched in August 2019 as plans took shape and sought to lobby government to carry out a review of options for delivery of offshore wind infrastructure.

A review was eventually announced by government this summer, with National Grid publishing the first findings from its analysis in late September.

Savings of an integrated approach offshore – rather than handing each offshore windfarm a new connection onshore each time – were found to be greatest, up to 30%, where high levels of offshore wind need to be connected to parts of the onshore network already nearing operational limits, or where windfarms are located far from shore. For the east of England, this would see savings of £2.3bn.

There are potentially significant environmental and social benefits too, with the research finding that the number of onshore and offshore assets, cables and onshore landing points could be cut by 50%. The majority of technologies required for an integrated design are available now or will by 2030, it said, though added that high voltage direct current (HVDC) circuit breakers could help to realise the full benefits of an integrated solution. The report suggested a targeted innovation strategy could help to progress these assets to commercial use, allowing the UK to become a world leader in offshore grids.

The report was released alongside a consultation which is seeking to examine whether a more integrated approach to the connection of offshore renewable power and interconnectors would be more beneficial – for consumers, coastal communities and the environment – than the current approach.

The deadline for submissions is 28 October 2020. Once that date passes, the ESO will review the evidence, before submitting final reports to BEIS as part of the wider offshore transmission network review.