Offshore wind: A valuable ingredient in the UK’s future energy mix

In successive reports, including our recent advice on the Fifth Carbon Budget, the Committee has highlighted the potential for offshore wind in the UK. Our 2011 Renewable Energy Review suggested that upwards of 400 TWh of electricity per year (more than the total of current UK electricity consumption) could be generated in UK waters, particularly if floating offshore turbines are developed.

Although offshore wind currently costs almost twice as much as a new build gas plant, a detailed assessment produced for the CCC by BVG Associates for our 2015 Progress Report to Parliament suggests that offshore wind costs could fall to a point where it is cost competitive with new build gas plants in the UK provided they face the full cost of their carbon emissions.

Ongoing innovation in offshore wind relies upon a visible future market of sufficient size across Europe, within which the UK is the largest player. That visibility can be provided by an extension of the existing policy framework and further clarity about the incentives for low-carbon investment in the 2020s. We recommended that the Government extends funding under the Levy Control Framework to at least 2025 and continues to offer low-carbon contracts via auction. Within this, offshore wind should be supported until it is cost competitive with a new build unabated gas plant by setting out an intention to contract 1-2 GW per year, provided costs fall, and with a view to removing subsidy in the 2020s.

After completing our study on the cost reduction opportunities for offshore wind, the CCC power analysts took a trip to see an offshore wind farm in action. The English North Sea coast, with its gently sloping shores, boasts some of the world’s best offshore wind sites. Towering above the sea, some five miles east of Brightlingsea in Essex stand 50 turbines rotating against the westerly winds. This is where DONG Energy’s Gunfleet Sands offshore wind farm – a 172 MW site which opened in 2010 – can be found. DONG, a Danish energy company, is currently the largest investor in the UK offshore wind sector.

The trip provided an opportunity to observe the latest technological innovation in wind-generated power in action. The 17,5km2 site features 3.6 MW turbines and two of the latest 6 MW turbines – installed on a demonstration basis – standing at around 172 metres tall, with blades measuring 60 metres across. Collectively, they provide an annual electricity output equivalent to the consumption of 200,000 British homes. Although we visited on a relatively calm day, the wind farm was producing around one third of its maximum capacity (55 MW) and produced, on average, an impressive 49% of its total power rating in 2014 – well above the 42% average for UK offshore wind.

Once installed, these turbines can work continuously for up to 25 years with regular maintenance. A team of 10 DONG Energy technicians are on hand 12 hours a day, five days a week, to ensure the turbines are available as much as is technically feasible. In all, the team carries out maintenance approximately 80% of the year, only failing to make it out to sea in periods of extreme weather.

The vast potential of offshore wind is immediately apparent. Gunfleet itself covers a huge area, and looks across the sea towards the much larger London Array project turbines dotted across the horizon. At 630 MW, London Array is currently the largest offshore wind farm in the world. In total, offshore wind generated 13 TWh in 2014, or 4% of the UK’s total electricity generation.

Since our trip, the Committee has published its advice on the fifth carbon budget, recommending a reduction in emissions of 57% on 1990 levels by 2030 as the next step towards a low-carbon economy in the UK. If suitably supported, offshore wind can make a significant contribution to meeting that objective, as set out in our latest scenarios for the power sector.

Consistent with these scenarios and in line with the advice in our progress report, the Secretary of State for Energy and Climate Change, Amber Rudd, recently announced the Government’s intention to continue supporting offshore wind into the 2020s, providing costs continue to fall. If that approach proves successful then offshore wind could play a key part in the UK’s low-carbon future.

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