How Energy Infrastructure Projects Navigate Ecology Requirements

Ecology requirements for energy infrastructure projects are substantive and technically complex, and with the arrival of mandatory Biodiversity Net Gain (BNG) for Nationally Significant Infrastructure Projects (NSIPs) in November 2026, increasingly consequential to get right from the outset. For developers working through the Development Consent Order (DCO) process, understanding how those requirements apply at each stage is a prerequisite for a project that can be examined and consented. 

This post sets out what energy infrastructure projects are required to do ecologically, covering the Ecological Impact Assessment (EcIA) process, the protected species most commonly encountered on transmission and generation routes, and the mandatory Biodiversity Net Gain framework that applies to Nationally Significant Infrastructure Projects from November 2026. 

The EcIA process: purpose and structure 

An EcIA is the formal process by which the ecological effects of a proposed development are identified, quantified and evaluated. For energy infrastructure projects proceeding through the DCO process under the Planning Act 2008, the EcIA typically forms the biodiversity chapter of the Environmental Statement submitted to the Planning Inspectorate. 

The industry standard for EcIA methodology is the Guidelines for Ecological Impact Assessment in the UK and Ireland, published by the Chartered Institute of Ecology and Environmental Management (CIEEM). Version 1.3 (September 2024) of those guidelines is currently in effect. 

The EcIA process follows a structured sequence. The starting point is a Preliminary Ecological Appraisal (PEA), comprising a desk study; drawing on datasets from Natural England, local record centres and biological recording networks, and UKHab mapping of onsite habitats. The PEA determines which habitats and species require further targeted survey work. On large linear projects, such as new transmission lines or underground cable routes, the zone of influence extends along the full length of the proposed route plus an appropriate buffer, which can mean surveys across dozens of different land parcels and multiple local authority areas. 

Where the PEA identifies potential for important ecological features, Phase 2 surveys follow. These are species-specific, seasonally constrained, and governed by Natural England licence requirements. The outputs feed into the main body of the EcIA which is as follows: the identification and evaluation of ecological features, the assessment of the significance of impacts during construction and operation, the application of the mitigation hierarchy, and the design of a strategy to avoid, reduce, mitigate and, where residual effects remain, compensate for ecological harm. 

For NSIPs, the EcIA is submitted within the Environmental Statement alongside the DCO application to the Planning Inspectorate. It informs the Examining Authority's scrutiny of the scheme and is a material consideration in the Secretary of State's decision. 

Protected species on energy transmission routes 

The ecological challenge of energy infrastructure is partly one of scale. A single high-voltage overhead line or underground cable route may pass through tens of kilometres of mixed landscape, crossing agricultural land, woodland, watercourses, wetland and heathland. The range of protected species likely to be encountered across such a route is therefore broader than on most planning applications, and the survey programme required to characterise their presence, distribution and status is correspondingly extensive. 

The species most regularly encountered on energy transmission and generation projects include the following. 

Bats 
All UK bat species are European Protected Species (EPS) under the Habitats Regulations 2017. They are fully protected from deliberate disturbance, and their roosts are protected whether bats are present or not. On transmission routes, bats are of particular relevance where the route passes through or adjacent to woodland, hedgerow networks, mature trees, or buildings. Survey requirements range from a Preliminary Roost Assessment (PRA) to emergence and re-entry surveys, bat transects along the route, and acoustic monitoring to characterise commuting and foraging activity. Linear infrastructure has the potential to sever commuting routes or remove roost features. Mitigation typically addresses both through design modification and, where necessary, EPS Mitigation Licences issued by Natural England. 

Otters 
The otter is an EPS fully protected under the Habitats Regulations. Its holts; the breeding and resting structures used by the species, are protected at all times. Any project crossing or running alongside watercourses must survey for otter presence and activity. On projects with multiple river and stream crossings, this can mean a substantial programme of otter surveys across the full survey season. Where construction would affect bank or riparian habitat, mitigation must account for both the animal and its habitat, and a mitigation licence is required where disturbance to otters or their holts cannot be avoided. 

Great crested newts 
The great crested newt is an EPS and one of four amphibian species listed as a species of principal importance under the Natural Environment and Rural Communities (NERC) Act 2006. It is found throughout mainland Britain, though distribution is uneven. Surveys are required where the route passes within an appropriate buffer of ponds with suitable habitat, and traditional survey methodologies require multiple visits between mid-March and mid-June. Environmental DNA (eDNA) analysis is now accepted by Natural England as an alternative to conventional survey in that period, enabling more efficient detection. Where great crested newts are present, a mitigation strategy must be developed and agreed with Natural England before construction can proceed. In areas where a District Level Licensing (DLL) scheme operates, this can offer an alternative to a project-specific mitigation licence, allowing developers to meet their obligations through a conservation payment into a strategic pond-creation programme rather than a bespoke survey and mitigation package. Scheme coverage is not universal, so checking whether DLL operates along a given route should form part of early survey planning. 

Water voles 
Water voles are protected under the Wildlife and Countryside Act 1981 from intentional killing, injuring or taking. They are also listed as a principal importance species under the NERC Act. On energy infrastructure projects, water vole surveys are triggered wherever the route traverses riparian habitat such as the margins of rivers, streams, ditches and drainage channels. Populations have declined markedly in the UK, and their presence on a route can require significant mitigation planning, including translocation where habitat loss cannot be avoided. 

Breeding birds 
All wild bird species are protected under the Wildlife and Countryside Act 1981 during the active nesting season. For energy infrastructure, bird surveys typically include breeding bird transects along the route, targeted surveys for Schedule 1 species where appropriate, and, for projects involving overhead lines, assessment of flight line risk, particularly for raptors and other collision-sensitive species. Vantage point surveys may be required to characterise bird movement patterns where elevated collision risk is identified. 

Reptiles 
Common lizard, slow worm, grass snake and adder are protected from intentional killing, injuring or sale under the Wildlife and Countryside Act 1981. Sand lizard and smooth snake carry full Schedule 5 protection as species of European importance. Reptile surveys are required where the route or works area includes suitable habitat such as rough grassland, scrub edges, embankments, or brownfield land with warm, sheltered aspects. Where significant reptile populations are present, translocation may be requiredprior to vegetation clearance. 

Hazel dormice 
The dormouse is an EPS fully protected under the Habitats Regulations. It is most frequently encountered on routes passing through or alongside ancient or semi-natural woodland and mature hedgerow networks. Dormouse surveys involve the deployment of nest tubes or footprint tunnels over multiple survey seasons, and the results have implications for both route design and construction methodology. 

Badgers 
Badgers and their setts are protected under the Protection of Badgers Act 1992. Badger surveys are required as a standard component of most EcIA programmes, with particular attention paid to any active main setts within or adjacent to the works footprint. 

On longer transmission routes, it is common for an EcIA to encounter several of the species above at once. Survey design must account for seasonal constraints, since many species can only be reliably surveyed within defined windows, and the programme must be sequenced to ensure the data needed for the EcIA and any mitigation licence applications is available before consent is sought. This places significant importance on early ecology input into project programming. 

Biodiversity Net Gain for NSIPs: the position from November 2026 

Energy infrastructure projects meeting the thresholds set out in the Planning Act 2008 are NSIPs and require a DCO rather than planning permission under the Town and Country Planning Act (TCPA) 1990. Mandatory BNG has applied to TCPA developments in England since February 2024. From 2 November 2026, it will also apply to NSIPs. 

The position has now been confirmed in detail. In April 2026, the government announced that mandatory BNG would apply to all NSIP applications submitted to the Planning Inspectorate on or after 2 November 2026. In May 2026, Defra laid biodiversity gain statements before Parliament for every NSIP category. In June 2026, the final versions of those statements, along with supporting guidance on how BNG must be calculated, delivered and reported, were published. The energy sector has its own biodiversity gain statement, tied to the relevant National Policy Statements for energy infrastructure. 

The core requirement is a 10% biodiversity net gain: the biodiversity value attributable to a development must exceed the pre-development biodiversity value of the on-site habitat by at least 10%. The government has applied this requirement consistently across all NSIP types, without sector-specific exemptions. The 10% threshold matches the existing TCPA requirement. 

Several features of the NSIP BNG framework are specific to the consenting context and differ materially from how BNG operates for smaller TCPA developments. 

The BNG boundary is defined more narrowly for NSIPs. Unlike TCPA applications, where all habitats within the site boundary are included in pre-development calculations, the NSIP framework applies BNG only to habitats impacted by the development rather than to the entire order limits. This is a significant practical concession that reflects the nature of linear infrastructure, where the order limits may be substantially larger than the actual construction footprint. 

Temporary land use is treated separately. Where habitat is temporarily disturbed during construction and reinstated to the same type and condition, this is treated as non-significant and does not need to be secured. This is intended to prevent BNG obligations from being duplicated across restoration provisions that are already standard practice in infrastructure consenting. 

Off-site delivery is explicitly supported as a first-instance option. For smaller TCPA developments, the mitigation hierarchy is structured to favour on-site delivery, with off-site as a secondary route. For NSIPs, Defra has recognised that strategic off-site delivery may in some cases produce better ecological outcomes than on-site provision, and has confirmed that off-site units may be used from the outset rather than as a fallback. Statutory biodiversity credits remain available only as a last resort, where both on-site and off-site routes have been exhausted. 

NSIP applicants must submit a BNG boundary plan as part of their Outline Biodiversity Gain Plan, clearly distinguishing impacted, contributory, retained and excluded habitats. This requires early-stage mapping that integrates with the broader EcIA baseline work and must be developed alongside, not after, route selection and design. 

The mandatory requirement does not apply retrospectively. Applications submitted before 2 November 2026 are not caught by the new regime, regardless of when the DCO is granted. Given the timelines involved in DCO examination, typically a minimum of several years from pre-application engagement to decision, many projects now entering pre-application phases will be submitting after the threshold date. The effective preparation window is therefore shorter than the nominal lead time suggests. 

Implications for project programming 

The ecology requirements for energy NSIPs are not, in aggregate, a single procedural hurdle at the point of application. They are a programme-spanning discipline that shapes route selection, design, construction methodology, and the conditions secured through the DCO. 

Baseline survey work must begin early enough to capture the full seasonal windows for all relevant species. On a large project, that typically means survey programmes running over two or more field seasons before submission. The EcIA methodology, zone of influence, and survey scope should be agreed with the Planning Inspectorate's pre-application service and, where relevant, with Natural England before surveys begin. 

The BNG Outline Biodiversity Gain Plan, and the underlying habitat mapping that informs it, must be developed in parallel with the EcIA baseline rather than assembled from it retrospectively. Given the interaction between BNG calculations, mitigation licence requirements, and any off-site habitat creation strategy, ecology needs to be embedded in the project team from pre-application through to the agreement of DCO requirements. 

The Ecology Co-op works with energy infrastructure clients across the full project lifecycle, from early-stage ecological appraisal and survey programming through to EcIA preparation, pre-application stakeholder engagement with Natural England and the Planning Inspectorate, protected species licensing, and BNG strategy development. For further information on how we can support your project, please get in touch.