This update highlights what we consider to be the most interesting and topical events from 1 July – 22 August 2025 within the Nationally Significant Infrastructure Projects ("NSIP") world, together with our opinions on key issues that matter to our clients.
1. Mona Offshore Wind Farm and Byers Gill Solar Farm DCOs granted
Summary
Between 1 July – 22 August 2025, Development Consent Orders ("DCOs") were granted for the Mona Offshore Wind Farm and the Byers Gill Solar Farm projects.
Key facts
On 4 July 2025, the Secretary of State ("SoS") for Energy Security and Net Zero granted development consent for the Mona Offshore Wind Farm, a 1500 MW wind farm to be situated in the Irish Sea off the northern coast of Wales. The project page is here, the decision letter is here and the made Order here.
On 23 July 2025, the SoS for Energy Security and Net Zero granted development consent for the Byers Gill Solar Farm, a 180 MW solar farm with battery storage to be located near Stockton and Darlington in the North-East. The project page is here, the decision letter is here and the made Order here.
Further analysis
Mona Offshore Wind Farm
The Mona decision was made by the SoS 12 days ahead of the statutory deadline (a welcome change from the many recent delayed decisions!) following the Examining Authority ("ExA") recommending approval.
The primary issue of note for offshore wind developers in the decision is the SoS' strong criticism of the developer for not providing a wake assessment (i.e. assessing the effects of reduced wind speed and turbulence downstream of Mona's turbines) on several Orsted wind farms in the vicinity. Wake effects are expected to be an increasingly common issue for offshore wind farms going forwards given the number of projects now established and still coming forwards in the Irish Sea and North Sea. National Policy Statement ("NPS") EN-3 requires a proposed offshore wind farm to carry out an assessment of said effects where the project is "close to existing operational offshore infrastructure" or "has the potential to affect activities for which a licence has been issued by government".
The Mona developer had argued that Orsted's wind farms were not "close" to the proposed development (being 30 km away) and that the policy reference to "licence" does not encompass a consent to operate a wind farm. The SoS rejected these arguments, describing them as "unhelpful and overly legalistic", and concluded that a project is "unarguably "close" enough to be relevant if it is accepted that there is a direct physical impact on that project" and that the semantic argument over the word "licence" was "misguided". The SoS relied upon an indicative report on wake effects submitted into the examination by Orsted and imposed a new requirement requiring a wake effects plan or evidence that alternative provision for wake effects had been agreed with Orsted to be submitted for approval by the SoS prior to construction of any wind turbines. Clearly incentivised by this requirement, the Mona developer and Orsted concluded a wake mitigation agreement on 14 August 2025 to manage the interaction between their projects, the details of which have not been made public.
The Mona DCO is also the latest to respond to the SoS' statutory duty in respect of protected landscapes under section 85 of the Countryside and Rights of Way Act 2000 and section 11A of the National Parks and Access to the Countryside Act 1949. Here, the developer pre-empted concerns with the duties by committing to provide a fund totalling £2.4 million over 35 years for projects to enhance the Anglesey National Landscape and Eryri National Park (Requirement 30, by reference to the developer's Landscape Enhancement Scheme Principles). Interestingly, both of the protected landscapes in question are located in Wales and, therefore, the duty remains to "have regard to" rather than the enhanced duty in England to "seek to further" the relevant purposes. Therefore, the funding provision secured through the Mona DCO is not necessarily indicative of what an acceptable approach would be under the enhanced test.
Byers Gill Solar Farm
The Byers Gill decision was made by the SoS on its due date (that's two-for-two on time!). The ExA recommended approval and the decision was taken by Parliamentary Under Secretary of State, Miatta Fahnbulleh MP, presumably to avoid any issues arising from the project site being near to Ed Miliband's constituency of Doncaster North. The decision is the third to be decided under the updated 2024 National Policy Statements ("NPSs").
The decision is largely in line with the recent flurry of solar DCOs being granted by the SoS. As has come to be expected, landscape and visual effects were afforded "great negative weight" by the ExA and SoS and effects on historic environment were afforded "moderate negative weight". The SoS also uprated the negative weight to be afforded to land use from the ExA's "little negative" to "moderate negative" to reflect the moderate adverse cumulative effects with other developments and the lack of mitigation available. Ultimately, however, these negative impacts were "significantly outweighed" by the benefits of the proposed development and the substantial positive weight attributed to its "contribution to the national supply of renewable energy and the urgent need for low-carbon infrastructure".
The SoS amended the DCO to require the developer to secure a minimum of 80% biodiversity net gain ("BNG") in habitats units and a minimum of 100% in hedgerow units, following the recent trend (seen in other decisions such as the Cottam, Heckington Fen and West Burton solar farm DCOs) to secure percentages higher than the statutory 10% (which in any event currently only applies to non-NSIP applications). The developer had proposed that the requirement only include the 10% figure but the SoS noted that NPS EN-1 paragraph 5.4.44 requires the SoS to consider securing BNG measures that are offered by an applicant. The developer can perhaps take some comfort that the SoS was generous enough to round down the percentages by 8% from the 88% and 108% claimed in the developer's application documents "to afford some leeway to account for extenuating circumstances or amendments to the applicable BNG metric"!
2. EIA guidance published for assessing effects of downstream scope 3 emissions for offshore oil and gas projects – clarification or confusion?
Summary
On 1 June 2025, the Department for Energy Security and Net Zero published supplementary EIA guidance for the assessment of effects of downstream scope 3 emissions. The guidance is principally intended to provide clarificatory guidance to offshore oil and gas developers seeking development and production consents in light of the Supreme Court judgment in the appeal case R (on the application of Finch on behalf of the Weald Action Group) v Surrey County Council and others ("the Finch case").
The published guidance is published here.
Key facts
- A consultation on an earlier version of draft guidance was previously carried out in October 2024 (we have a comparison copy available in case any reader is interested), which we previously commented upon in our edition of this newsletter at the time (Section 1 here).
- The guidance is supplementary to the Offshore Petroleum Regulator for Environment and Decommissioning's (OPRED) existing EIA guidance (here), which is not proposed to change in light of the Finch judgment.
- The guidance is specifically targeted at the offshore oil and gas sector and does not cover/contemplate development from other sectors.
- The guidance is presented as intending to be helpful, rather than prescriptive, and expressly notes it is not "a definitive statement of the law or to constitute legal advice" and recognises it is for developers and their competent experts to determine how to appropriately assess the effects of a project on the environment and that "alternative approaches may be possible or even preferable, either now or as approaches and scientific understanding develop over time".
Further analysis
Our previous commentary noted the draft was a helpful starting point, but suggested changes/additional clarification would be welcomed in certain areas to avoid being potentially self-defeating in its attempt to bring clarity and guidance to those producing environmental statements in this area. In particular, we highlighted concerns around the language/approach proposed in terms of the setting of the baseline environment, the appropriate contextualisation of the scope 3 emissions to assist with determining the significance of the effect and what is required by way of cumulative assessment. There's been a number of changes in the published guidance in respect of each of these areas; however, not all in a necessarily helpful direction (from a developer/practitioner's perspective) in our opinion.
For the determination of the baseline – the previous text has been removed in its entirety and instead its stated that "when determining the baseline scenario for scope 3 emissions, the location of the emissions is not relevant and a global baseline scenario of GHGs must be considered in the ES", with a reasonable future estimate of the global GHGs affecting climate also to be outlined to address the future baseline scenario. Reference is made to particular sources of environmental information and scientific knowledge to inform that global GHG baseline.
In terms of contextualisation of the project's scope 3 emissions – the guidance notes OPRED's current view is that "characterising scope 3 emissions from a project solely in numeric terms against global GHG emissions would not on its own provide a meaningful expression of the global effect of those scope 3 emissions, because of the obvious difference in scale between individual projects and global emissions levels. Therefore, OPRED considers that an assessment of scope 3 emissions in relation to the current state of climate and global emissions-reduction pathways (IPCC, 2023) is more likely to support a reasoned conclusion on significance."
Finally in terms of the cumulative assessment – it is stated that the "ES must consider the cumulative effects of the proposed project with other existing and planned future projects, in a global context. If global reduction pathways are used to contextualise magnitude of emissions as above, this approach should be inherently cumulative, as these pathways take into account a wide range of existing and planned projects and other activities. Alternatively, or in addition, developers may choose to use information from global oil and gas datasets and inventories."
It is appreciated that this is still a developing area of EIA practice in view of the interpretation of the Supreme Court's judgment; however, it seems, frankly, absurd that the output of clarificatory guidance intended to assist developers requires individual projects to consider in their ES the potential effects of a project's scope 3 emissions at a national and global level, alone and in combination with other global projects (both existing and planned), set against the current state of climate and global emissions-reduction pathways. It is difficult to see a scenario in which that could ever provide genuinely useful environmental information to inform a decision on a project's potential impacts.
We suspect further updates will be required once EIA practitioners have debated and/or the courts have further considered.
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