'Wind theft': global power giants quietly battle over six offshore projects

Orsted, TotalEnergies and RWE are among the leading offshore wind developers quietly fighting legal battles over wind wakes concerning more than 20GW of projects, raising awkward and thorny issues that could dampen sector growth.

As more huge offshore wind arrays crowd into the North Sea and neighbouring waters, developers are increasingly concerned that – even for projects separated by tens of kilometres – things are getting a little too cosy.

They are specifically concerned about wind wakes, stretches of lower-intensity wind that turbines leave trailing behind them. Research has shown that these wakes can stretch over vast distances, as far as 100km offshore.

Developers fear that newcomer projects will ‘steal’ wind from their existing wind farms – ‘wind theft,’ as it is sometimes known – reducing power generation and, in turn, revenues.

Owners of incumbent wind farms are now raising objections against new developments in planning proceedings. If these newcomers are going to take some of ‘their’ wind, incumbents are clear: they want mitigation, money or both.

A UK examining authority last year ruled that RWE’s up to 1.1GW Awel y Môr offshore wind farm could go ahead but only on the condition it first assesses how much wind it will take from an existing neighbour and provide mitigation.

This was a groundbreaking decision that is now central in other ongoing disputes over wind wakes that have blown up in planning proceedings for six prospective new wind farms off the coast of England & Wales.

Dogger Bank South (RWE and Masdar vs SSE, Equinor, Vårgrønn and Orsted)

RWE has already felt the sharp end of the UK planning system on wind wakes and is now embroiled in another dispute concerning the 3GW Dogger Bank South project it is developing with Emirati renewables giant Masdar.

SSE, the lead development partner for Dogger Bank A, B and C, a trio of projects totalling 3.6GW that it owns with Norway’s Equinor and Vårgrønn, has raised objections in planning procedures over the newcomer’s potential wake effects on its projects.

SSE argues that RWE has acknowledged its project could cause wake losses at Dogger Bank A and must now carry out a full assessment, including for Dogger Bank B and C, as in the Awel y Môr case.

RWE counters that the wake losses would be “negligible when compared to the wind resource available.” What developers see as “negligible” will no doubt be of intense further debate.

The German utility also argues that it should not have to carry out an assessment because its project complies with the 7.5km buffer zone between projects stipulated by the seabed landlord for England & Wales, The Crown Estate.

It also noted a study The Crown Estate commissioned on wake effects from Frazer-Nash Consultancy, which found that they level off after 10km and for separations “much larger than 20km” become “vanishingly small.”

Frazer-Nash relied on a TurbOPark wind wake model developed by Orsted for its study. Orsted’s own research using its model has found that wake effects can cause an almost 30% drop in resource at the front row of turbines at a wind farm even when projects are 20km apart.

This may be why Orsted has also intervened in the Dogger Bank South process on behalf of its Hornsea 3 and Hornsea 4 wind farms, with 5.5GW combined capacity, which are planned up to 45km away.

It argues there is “significant potential” for Dogger Bank South to “interfere with wind speed or wind direction and thus cause a reduction in energy output” at its projects.

RWE is itself a leader in wind wake research. Its offshore wind chief Sven Utermöhlen said last year the developer’s own wake models “predict that large clusters of offshore wind farms could have far-reaching wind-shadowing effects, over a distance of up to 200km or more,” although those findings were preliminary and research remains ongoing.

Outer Dowsing (Corio and TotalEnergies vs Orsted)

Orsted has also raised concerns over wake losses impacting its four Hornsea projects – totalling around 8GW – in the planning procedure for the Outer Dowsing wind farm, which TotalEnergies and Corio Generation are developing.

Orsted again argues that “given the proximity” of the 1.5GW Outer Dowsing project to its existing and planned Hornsea sites, which range between around 20-40km away from the proposed newcomer, there is “significant potential” for it to impact power production.

Orsted said it noted TotalEnergies and Corio’s position that Outer Dowsing complies with The Crown Estate’s 7.5km spacing requirement, but that “does not negate” the need to “engage on this issue and consider any evidence presented”.

The examining authority asked TotalEnergies and Corio to conduct a wake assessment for the project or explain why they shouldn’t have to. In response, they argue that the relevant regulations do not require them to assess an effect that is “not likely to be significant.”

Referring to the Frazer-Nash study, they argue an effect that is “‘vanishingly small’ or even simply ‘small’ cannot reasonably be said to be significant.”

Mitigating against wake effects impacting many different projects would in any case be near impossible, they argue. Adjusting the position of turbines at Outer Dowsing might after all lessen wake effects on one neighbour while increasing it on another.

This is further complicated by the fact that Orsted’s 580MW Race Bank wind farm, 23.5km away, has also raised concerns over wakes; as has the 270MW Lincs offshore wind farm, which is 46km away and counts Corio owner Macquarie, Orsted and Octopus Renewables as major shareholders.

The unspoken mitigation measure is of course monetary compensation, with some developers having already entered wake loss agreements to help resolve disputes or avoid them entirely.

Morgan, Mona and Morecambe (EnBW, BP, Cobra and Flotation Energy vs Orsted)

This is a three-in-one bust-up currently taking place in the Irish Sea concerning proposed projects called Morgan, Mona and Morecambe.

German developer EnBW and oil major BP are developing Morgan and Mona, each boasting 1.5GW of capacity, while Spain’s Cobra and Scotland’s Flotation Energy are partnering on the 480MW Morecambe project.

All three have attracted attention from Orsted, the owner of six incumbent wind farms: its 90MW Barrow and Burbo Bank projects; a 258MW Burbo extension; and its trio of Walney wind farms together boasting 1.1GW of capacity.

In a submission in the Morgan proceeding last month, Orsted said that its own preliminary modelling indicates Morgan will result in an up to 3.5% loss of annual energy production at its projects. The cumulative effects from all three new projects are it says up to 5.3%.

The examining authority has recently asked Orsted to submit further evidence to back up its claims, with an “explanation of the modelling used and a summarised justification for the quoted figures.” It also asked for clarification on whether this estimate was for loss at front row turbines only.

At a 26 November hearing, a Morgan representative argued that while every company has its own wake assessment model and the developers “could very easily spend the rest of this examination arguing about both the appropriateness and limitations of any modelling tools… that would be a complete and utter waste of everybody's time.”

Alluding to the other pending disputes, they said there could potentially be a situation where each examining authority comes to different conclusions on whether newcomer projects have to carry out wake modelling.

“Our position is there is no policy requirement for this. And if there was, it has to be driven by the Secretary of State,” in this case UK energy secretary Ed Miliband.

They also argued that while Orsted had agreed to provide confidential information from its operational wind farms under a non-disclosure agreement to support its modelling estimates, this would be “simply wrong” and calls into question whether Orsted is “actually interested in an open and transparent approach to assessment.”

Five Estuaries (RWE and others vs Iberdrola)

In waters off England’s southeastern coast, RWE is developing the Five Estuaries offshore wind farm. It owns a 33.3% stake in the project with other minority shareholders including a Macquarie-led consortium (25%), Irish state-owned utility ESB and Japan’s Sumitomo Corporation (both 21%).

The 1.1GW project has not escaped the attention of Iberdrola subsidiary ScottishPower, which owns the East Anglia One, Two and Three projects.

East Anglia Two is located just over 5km northeast of the application boundary and Iberdrola said last month that the newcomer project will inevitably cause wake losses. “Given the proximity, it is likely that the losses will be material.”

“It is notable that the Applicant has not sought in the application material to acknowledge this effect,” said Iberdrola.

More creatively, Iberdrola argues these effects must be accounted for under English Habitats Regulations. These require assessment of how much harm infrastructure projects will cause habitats and for this to be weighed against their benefits – in this case green power produced.

Iberdrola argues – as does Orsted, which is relying on the same law firm, Shepherd and Wedderburn, in separate proceedings – that this assessment must not only consider the additional power Five Estuaries will generate but the loss of power it will cause through wake effects at neighbouring sites.

As in other cases, Iberdrola is arguing that the newcomer project is “best placed” to address and quantify these concerns by carrying out a wake impact assessment.

RWE argues that its compliance with the 5km buffer area which The Crown Estate required at that time is a basis for not justifying carrying out an assessment. Iberdrola counters that “a landlord’s relationship with a tenant could never be the basis for an argument that an assessment should not be undertaken.”

Iberdrola cites a submission from The Crown Estate in which it acknowledges that wind wakes travel further than 7.5km (or indeed 5km, in this case) and says its commissioning of the Frazer-Nash study was not intended to stop developers from using “other studies and evidence” for specific projects.

The Crown Estate has found itself in a particularly awkward position as seabed landlord, not wanting to upset any of its tenants while also having an imperative to try and encourage as much offshore development as possible.

It declined to comment for this article, saying it wouldn’t do so on issues relating to live consenting processes. Given wind wakes will almost certainly be a permanent fixture in these processes going forward, it appears unlikely it will say anything on the topic any time soon.