Terry Slavin reports on how falling costs, technology breakthroughs to allow wind energy to be produced far out at sea, and growing demand for green hydrogen are driving a rapid expansion in ocean-based power production

Oceans are critical in the battle against climate change, absorbing 25%-30% of annual CO2 emissions, but it is a role that is being undermined as oceans warm and become more acidic. In the future, scientists say, the greatest CO2 mitigation potential will have to be found not in the depths of the oceans, but in what lies on top: renewable energy installations like offshore wind, wave and tidal energy and floating solar arrays.

The High Level Panel for a Sustainable Ocean Economy envisages ocean-based renewable energy will account for 5.4 GtCOe (gigatons of CO2 equivalent) of the 11.8 GtCO2e mitigation potential of the oceans by 2050, delivering one fifth of the cuts necessary to help keeping global temperature rises below 1.5C.

That is almost as much as all other ocean-based climate solutions the panel cites combined. And much of the heavy lifting will come down to one technology: offshore wind.

The 1,400GW target for wind is ambitious but absolutely doable

Offshore wind today only accounts for 0.3% of power generation globally, with a total installed capacity of 29GW. But that is literally a drop in the ocean of its potential, according to the IEA, which says there is enough offshore wind resource globally to meet total global electricity demand 18 times over.

And the industry is scaling up rapidly, amid dramatic falls in cost, increases in turbine sizes, and recognition in Europe of its critical role in fostering a green hydrogen economy (see below).

BloombergNEF reported last month that offshore wind had defied the Covid-19 downturn, seeing $35bn investment in the first half of this year, up 319% on the previous year, with green lights given to 28 sea-based windfarms, including the 1.5GW Vattenfall Hollandse Zuid project off the coast of the Netherlands, the 1.1GW SSE Seagreen project in the UK, and 17 projects in China, where investors rushed to take advantage of a feed-in tariff due to expire at the end of 2021.

Estimates suggest there is enough offshore wind resource to meet total global electricity demand 18 times over.  (Credit: Vattenfall)

While current forecasts are for capacity to reach 190GW by 2030, and 350 GW by 2040, in June, the Ocean Renewable Energy Action Coalition (Oreac), a group led by offshore wind energy majors Ørsted and Equinor, announced an ambition to install 1,400 GW of offshore wind globally by 2050.

John Olav Tande, offshore wind specialist at Norway’s SINTEF, an independent research organisation, said in an interview that the 1,400GW target for wind was “ambitious but absolutely doable and would be a very important step to reach climate targets.”

He added that because the space covered by oceans is much larger than land ”it is possible to find places where there are opportunities to do really large projects with little or negligible environmental impact” if proper planning and surveys are conducted to assess impacts of birds and sea mammals.

This demonstrates that offshore wind is key to enabling the UK to become carbon neutral by 2050

The UK, which has a target of 30GW of offshore wind capacity by 2030 to help meet its climate goals, is sitting world leader, having already commissioned 6GW to date, including the 3.6GW Dogger Bank wind farm, 130 kms off the Yorkshire coast in the North Sea.

The project, a partnership between Norwegian oil major Equinor and SSE Renewables, will cover an estimated 5% of the UK’s electricity generation when it is up and running in 2023, and produce electricity for about £40 per megawatt hour.

“This success demonstrates that offshore wind is the key technology to enable the UK to become carbon neutral by 2050 in the most cost-effective way, whilst also delivering significant economic benefits across the country,” said Jim Smith, managing director of SSE Renewables, when the £9bn project was announced last September.

Surveys need to assess the impact of ocean wind on birds and sea mammals.  (Credit: Ondrej Prosicky/Shutterstock)


The UK is also the location of the world’s only commercial floating wind installation, Equinor’s 30MW Hywind Scotland, a pilot project that has been operating off the Aberdeenshire coast in 105m of water since October 2017, much deeper than the 20m to 50m at which conventional offshore wind turbines are installed.

The five turbines have been reaching 65% of their maximum capacity even in hurricane conditions, a vast improvement on the average 40-50% capacity of land-based turbines.

Tande sees floating wind turbines as critical to fulfilling the technology’s potential because they can be installed in areas with deep water, where 80% of the world’s wind resource is located.

We are seeing big developers from bottom-fixed and oil and gas majors moving into floating wind

In some geographies, like large parts of the coast in North America, Japan or Norway, floating wind will be most suitable because of the water depth, Tande said.

“I think floating wind will be a big part of 1400GW. But we need R&D to scale up in the right way, and with the right technical solutions.”

Arne Eik, leading developer of floating offshore wind at Equinor, told The Ethical Corporation that although floating wind currently costs twice as much as bottom-fixed, the latter has seen its levelised costs of producing electricity, a measure of the average cost per megawatt hour over the full lifetime of a plant, cut in half in the past few years.

Equinor’s 30MW Hywind floating turbines have been operating off the Aberdeenshire coast since 2017. (Credit: Equinor)

He expects floating wind to follow the same trajectory, and fall to €40 per megawatt hour (MWh) by 2030, with bottom-fixed as low as €30 per MWh.

“We are seeing more projects coming, and we are also seeing big developers from bottom-fixed and oil and gas majors moving into floating wind,” a development that will allow the industry to get to scale and drive down costs.

Levalised costs have already come down 40% at Equinor’s second floating wind project, the 88MW Hywind Tampen, which is due to start operations in 2022, Eik said. Located 140 km off the Norwegian coast, Tampen will supply power to the Snorre and Gullfaks offshore oil and gas fields. The project, which has NOK 2.3bn in state support, is expected to reduce CO2 emissions by the installations by more than 200,000 tonnes per year.

Offshore wind speeds tend to increase in the evenings, when solar power supplies fall but air conditioner use soars

Eik said Equinor, which this year announced targets to reduce greenhouse gas emissions from its offshore oil and gas fields and onshore plants by 40% by 2030, has ambitions to retain the early world leadership it has established in floating wind.

Once commercial, Equinor sees the technology as crucial for opening up offshore wind opportunities in South Korea, Japan, China, Taiwan and the US state of California.

According to a 2016 NREL report, California has technical wind energy resource potential of at least 100GW off its coast, which it has been unable to exploit because its deep waters are unsuited to bottom-fixed offshore wind technology. Under the Donald Trump presidency, the US has also been opposed to renewables development in federal waters, something that could change if Joe Biden wins in November.

Hywind’s floating turbines measure 253m, higher than Big Ben. (Credit: Equinor)

The California Public Utilities Commission estimates that about 7 GW of offshore wind could be part of California’s ideal zero-carbon electricity mix by 2045, the target date for the state’s electricity to be zero-carbon.

Critically, offshore wind speeds tend to increase in the evenings, when solar power supplies fall but air conditioner use soars, one reason the recent heatwaves have pushed the state’s solar-power-heavy grid to the limits and forced the imposition of blackouts to balance supply and demand.

But there are hurdles that floating wind will have to overcome for the technology to become commercial, and it is not just down to cost. One looming challenge will be opposition from the global fishing industry.

Having an early dialogue process with other stakeholder interests at sea is key for offshore wind to succeed

“We’d like co-existence [with the fisheries industry] and we’d like to see marine spatial planning be developed to decide where to have fisheries and where to have offshore wind,” Eik said. “Having an early dialogue process with other stakeholder interests at sea is key for offshore wind to succeed. I’m very hopeful that we are getting there.”

Søren Lassen, senior offshore wind analyst for Wood Mackenzie, is also upbeat about the prospects for offshore wind, particularly beyond 2030. He said Oreac’s target to have 1,400 GW of offshore wind installed globally by 2050 “is a little bit crazy, but that doesn’t mean it can’t happen”.

Both floating and fixed-bottom wind will benefit from hundreds of millions of euros in EU funding earmarked for green hydrogen in its coronavirus recovery package and Green New Deal.

Despite the Covid-19 pandemic, investment in sea-based wind farms rose 319% this year. (Credit: DJ Mattaar/Shutterstock)

And Lassen pointed to recent announcements by countries including South Korea, which aims to have 12GW of offshore wind installed by 2030, up from 100MW today, and French plans to boost its existing 2MW capacity to 12.4 GW by 2028, including 1.5GW of floating offshore wind.

“We already see policy targets [for offshore wind] from various governments of more than 200GW by 2035 and that isn’t the end. We expect more governments to set targets and for existing targets to be upgraded.”

And while the sheer size, complexity and lead time for floating wind concepts will limit investment in the near term, he believes it will be an increasingly important technology post 2025. “We are seeing more experienced players get on board and position themselves in this space” through alliances and memorandums of understanding, and some 75 different concepts for how it will develop being explored. “How it will look like I’m not sure, but I do believe it’s going to happen.”

Netherland’s wind-powered green hydrogen hub begins to take shape

(Credit: New Energy Coalition)

THE EU, which has a goal of cutting greenhouse gas emissions in half by 2030, sees a massive increase in offshore wind – from 20GW today to 450GW by 2050 – as necessary to fuel a green hydrogen economy, with electrolysers located either on land or built into wind towers at sea using renewable energy to convert seawater into zero-carbon hydrogen.

Not only could it provide zero-carbon fuel in industrial quantities for hard to decarbonise sectors like steel and long-distance trucking, green hydrogen could be converted to ammonia and used as a clean fuel for shipping.

The Netherlands is leading the way, announcing earlier this year plans to turn off the tap on natural gas production in the north of the country by 2025 and create a green hydrogen hub in its place, fuelled by offshore wind farms and using the same gas network infrastructure.

This began to take shape in July, when a consortium of Shell and Eneco secured the right to build the 759MW Hollandse Kust North project, 18.5 kilometres off the Dutch coast, which will generate 3.3 terrawatt hours (TWh) of wind per year.

By 2040 volumes could be 10MW, producing 800,000 tonnes of green hydrogen

Shell said the wind farm, which will come online in 2023, will also feature a floating solar park, and produce green hydrogen. While the hydrogen will initially be used to decarbonise production in Shell’s Pernis refinery, in future it would connect to the NortH2 green hydrogen hub in the Port of Rotterdam, projected to open in 2027.

While new partners will be required, the ambition is for new wind farms in the North Sea to feed 3-4MW of power a year into a mega-hydrogen facility in Eemshaven by 2030. By 2040 volumes could be 10MW, producing 800,000 tonnes of green hydrogen for industrial users in the Netherlands and northwest Europe, enough to avoid 7 megatons of CO2 emissions annually.

Another innovative idea is to locate floating wind installations on shipping routes, where ships would dock to fill up with clean ammonia fuel, produced in situ from hydrogen derived from seawater and nitrogen extracted from the air. This is a solution being promoted by the Zero Emission Energy Distribution at Sea (ZEEDs) initiative, led by Finnish energy company Wartsila, and including Aker Solutions, DFDS, Grieg Star, Kvaerner and Equinor.

Main picture credit: Shaun Wilkinson/Shutterstock


This article is part of our in-depth briefing, Sustainable oceans. See also:

Time is rapidly running out to save oceans

Using blockchain to bring transparency from sea to plate

Can sustainable aquaculture feed the world?

Big data employed to increase traceability in bid to to save the big blue sea

ESG investors slow to make waves in the $2.5tn ocean economy

Fashion ‘slow to act on ocean plastic pollution from microfibres’


Shell  hydrogen valley  High Level Panel for a Sustainable Ocean Economy  Wood Mackenzie  IEA  offshore wind  Hywind  Equinor  SSE Seagreen  Dogger Bank  Vattenfall  Hollandse Zuid  OREAC  ZEEDs  SSE Renewables  Orsted  Sintaf  California blackouts 

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