BNG NSIP November 2026: Nationally Significant Infrastructure Biodiversity Net Gain Explained

Last updated: August 23, 2026

Quick Answer: From 2 November 2026, mandatory Biodiversity Net Gain applies to Nationally Significant Infrastructure Projects in England under secondary legislation made under the Environment Act 2021. Any NSIP application submitted on or after that date must demonstrate a minimum 10% biodiversity net gain as part of its Development Consent Order process. Projects already in the DCO pipeline but not yet submitted face immediate pressure to commission baseline ecological surveys before the deadline.

Key Takeaways

• BNG NSIP November 2026 nationally significant infrastructure biodiversity net gain becomes mandatory for all NSIP applications submitted from 2 November 2026 onward.
• The 10% biodiversity gain objective applies across all NSIP categories: energy, transport, water, and waste infrastructure.
• Biodiversity gain requirements must be written into draft DCOs from the outset, not bolted on later.
• Transitional arrangements mean NSIPs with applications submitted before 2 November 2026 are not subject to the duty.
• August 2026 amendments to the wider BNG regime (0.2ha exemption, temporary development exemption) do not directly mirror NSIP rules, which have their own regulatory framework.
• Statutory biodiversity credits cost approximately £42,000 to £650,000 per unit; private off-site units typically range from £20,000 to £90,000.
• Ecology surveyors must act now: baseline surveys need to be timed correctly to be valid at the point of DCO submission.
• The NSIP BNG regime is front-loaded and DCO-centred, meaning the biodiversity gain statement is a core document, not an afterthought.

What Is Biodiversity Net Gain for Nationally Significant Infrastructure?

Biodiversity net gain for nationally significant infrastructure is the legal requirement for NSIP promoters to leave biodiversity in a measurably better state than before development. Under the Environment Act 2021 and its secondary legislation, the biodiversity gain objective for NSIPs requires that the post-development biodiversity value of the project footprint exceeds the pre-development baseline by at least 10% [3].

This is not a voluntary target. From 2 November 2026, it is a statutory duty embedded in the DCO process. The requirement applies only in England and only to the mean low-water mark, so offshore elements of energy projects, for example, fall outside its scope [4].

For a fuller grounding in how the metric works, see this biodiversity net gain explained guide from Biodiversity Surveyors.

What Types of Projects Count as Nationally Significant Infrastructure?

NSIPs are large-scale infrastructure projects that require a Development Consent Order rather than standard planning permission. The categories affected by BNG NSIP November 2026 nationally significant infrastructure biodiversity net gain rules include [4]:

• Energy: onshore and offshore generating stations above threshold capacity, electricity transmission lines, underground gas storage
• Transport: nationally significant highways, railways, rail freight interchanges, airports
• Water: reservoirs, water transfer projects
• Waste: hazardous waste facilities above threshold

The thresholds are set in the Planning Act 2008. Projects below those thresholds fall under standard Town and Country Planning Act BNG rules, which have been in force since April 2024 for major applications.

What Changed in BNG NSIP Rules in November 2026?

The duty to achieve 10% biodiversity net gain for NSIP applications takes effect on 2 November 2026. This is the single most significant change: before that date, no NSIP carried a statutory BNG obligation. Applications submitted from that date onward must include a biodiversity gain statement and demonstrate compliance through the statutory biodiversity metric [6].

The NSIP BNG regime is deliberately front-loaded. Draft DCOs must contain the biodiversity gain requirements from the start of the examination process, not as a condition to be discharged later [7]. This differs from the standard planning BNG regime, where conditions are common.

What about the August 2026 amendments? In August 2026, the government made secondary legislation amending the general BNG framework for standard planning applications. Key changes included:

• A 0.2-hectare de minimis exemption for small development footprints
• A revised temporary development exemption
• Removal of the self-build exemption that had previously applied to certain custom-build homes [1]

These amendments apply to Town and Country Planning Act applications, not directly to the NSIP regime, which operates under separate secondary legislation. However, they signal the government's continued willingness to refine BNG rules, and NSIP promoters should monitor for any equivalent NSIP-specific amendments before November [9].

How Does BNG Apply to NSIP Projects in the UK?

BNG applies to NSIP projects through a dedicated regulatory pathway that runs parallel to the standard planning BNG regime. The process works as follows [4] [6]:

1. The NSIP promoter commissions a baseline ecological survey using the statutory biodiversity metric.
2. A biodiversity gain statement is prepared, showing pre-development and post-development unit values.
3. The gain statement is submitted as part of the DCO application to the Planning Inspectorate.
4. On-site habitat creation or enhancement is the preferred route; off-site units or statutory credits are used to fill any remaining gap.
5. The DCO, once made, contains binding biodiversity gain requirements with a 30-year management obligation.

The Planning Inspectorate published sector-specific biodiversity gain statement guidance in June 2026, covering energy, transport, and water NSIPs separately [6]. Promoters should use the relevant sector guidance when structuring their applications.

How Do You Calculate Biodiversity Net Gain for Infrastructure?

Biodiversity net gain for infrastructure is calculated using the statutory biodiversity metric, a government-published tool that assigns unit values to habitats based on their type, condition, and size [5]. The calculation compares pre-development habitat units against post-development habitat units, including any created or enhanced habitats within the project boundary.

The 10% gain objective means the post-development total must be at least 110% of the pre-development baseline. For linear infrastructure such as roads or pipelines, this calculation can be complex because the project footprint is fragmented across multiple habitat parcels and land ownership boundaries.

For a detailed walkthrough of what a BNG assessment contains, see what is in a biodiversity net gain assessment.

Common mistake: Using an outdated version of the statutory metric. The metric has been updated since the original 2023 release. Always use the current version published on GOV.UK [5].

What Are the Exemptions from BNG Requirements for NSIP?

Not all NSIP-related development is automatically subject to the full BNG duty. Confirmed exemptions and carve-outs under the NSIP BNG framework include [4] [8]:

• Offshore development beyond the mean low-water mark
• Permitted development associated with an NSIP but authorised separately
• Development in marine plan areas governed by separate marine licensing

The 0.2ha de minimis exemption introduced in August 2026 applies to standard planning applications, not NSIPs. NSIP promoters should not assume this exemption transfers across regimes without specific legal advice.

There is no equivalent self-build exemption for NSIPs, which is consistent with the removal of that exemption from the standard regime in August 2026 [1].

How Much Does Biodiversity Net Gain Cost for Infrastructure Projects?

Cost depends on whether the developer achieves gain on-site, purchases off-site biodiversity units from the private market, or buys statutory biodiversity credits from the government as a last resort [3].

Statutory credits are intentionally priced at a premium to incentivise on-site and private off-site delivery first. For large NSIPs with significant habitat loss, the credit bill could run into millions of pounds if the project relies heavily on this route [7].

For a detailed breakdown of unit pricing, see cost of biodiversity units and statutory credits and the guide to buying biodiversity units.

Can You Offset Biodiversity Net Gain Off-Site Instead?

Yes, but only after demonstrating that on-site gain has been maximised. The BNG hierarchy for NSIPs follows the same principle as standard planning BNG: on-site first, off-site second, statutory credits last [3].

Off-site biodiversity units must be registered on the biodiversity gain site register and located in England. For linear infrastructure projects crossing multiple local planning authority areas, off-site units may need to be sourced from multiple locations to satisfy proximity requirements. See biodiversity net gain off-site or on-site delivery for a comparison of both approaches.

What Happens if You Don't Meet BNG Requirements for NSIP?

Failure to demonstrate 10% biodiversity net gain will result in the DCO application being refused or returned as incomplete. Because the NSIP BNG regime is front-loaded, a deficient biodiversity gain statement cannot simply be corrected by a planning condition after consent is granted [7].

In practice, this means the Planning Inspectorate will scrutinise the biodiversity gain statement during the examination. If the statement is inadequate, the promoter will need to revise it during the examination process, which can cause delays and additional costs.

How Long Do Biodiversity Net Gain Requirements Last After Project Completion?

The biodiversity gain obligation lasts for a minimum of 30 years from the date the habitat creation or enhancement begins. This applies to both on-site habitats and off-site biodiversity units. The 30-year management requirement is written into the DCO and is legally binding on the landowner, not just the project promoter [3] [4].

This has significant implications for NSIP promoters who do not own the land on which off-site habitats will be created. Long-term legal agreements with landowners must be in place before the DCO is made.

How Do Environmental Impact Assessments Relate to BNG for NSIP?

Environmental Impact Assessment and BNG are separate but closely linked processes for NSIPs. The EIA assesses the significance of biodiversity impacts; the BNG process quantifies those impacts using the statutory metric and demonstrates how the 10% gain objective will be met [8].

The biodiversity chapters of the Environmental Statement feed directly into the biodiversity gain statement. Baseline surveys conducted for EIA purposes can often be used for the BNG metric calculation, provided they meet the survey standards required by the metric methodology. This makes early survey timing critical: surveys that are too old at the point of DCO submission may need to be repeated.

For developers building projects in England, see how to create a biodiversity plan for developers.

What's the Difference Between BNG and Environmental Mitigation?

Environmental mitigation reduces or avoids harm to biodiversity; BNG goes further by requiring a net positive outcome. Mitigation measures such as habitat translocation or species compensation satisfy the mitigation hierarchy but do not automatically count toward the 10% gain target [3].

Under the statutory metric, only habitat creation and enhancement that goes beyond mitigation contributes to the biodiversity gain calculation. NSIP promoters who conflate mitigation with BNG delivery risk understating their residual biodiversity deficit and failing to meet the gain objective.

What Ecology Surveyors Need to Do Right Now

As of 23 August 2026, there are just over ten weeks until the 2 November 2026 deadline. For ecology surveyors working with NSIP promoters, the priority actions are:

• Commission or complete Phase 1 habitat surveys for any DCO application expected to be submitted after 2 November 2026. Survey data must be current at the point of submission; surveys older than two years are generally considered stale.
• Run the statutory biodiversity metric on existing survey data to identify whether the project can achieve 10% on-site, or whether off-site units or credits will be needed.
• Prepare draft biodiversity gain statements using the June 2026 sector-specific guidance published by the Planning Inspectorate [6].
• Identify off-site unit suppliers early, particularly for projects in areas with limited habitat creation opportunities.
• Review the August 2026 amendments to confirm whether any changes to the standard BNG regime affect associated permitted development linked to the NSIP.

For a practical checklist approach, see 8 biodiversity net gain points on planning your project.

FAQ

Q: Does BNG apply to NSIP applications submitted before 2 November 2026?
No. The statutory duty only attaches to NSIP applications submitted on or after 2 November 2026. Applications already submitted or accepted for examination before that date are not subject to the mandatory BNG requirement [4].

Q: Is the 10% BNG requirement the same for NSIPs as for standard planning applications?
Yes. The biodiversity gain objective is 10% in both regimes, calculated using the statutory biodiversity metric. The procedural pathway differs: NSIPs use a biodiversity gain statement within the DCO process rather than a pre-commencement condition [3].

Q: Can statutory biodiversity credits be used as the primary route to achieve BNG for an NSIP?
Technically yes, but statutory credits are a last-resort option and are priced to discourage their primary use. The government expects promoters to maximise on-site and off-site delivery first [3] [7].

Q: Do the August 2026 BNG amendments (0.2ha exemption, temporary development exemption) apply to NSIPs?
No. Those amendments were made to secondary legislation governing Town and Country Planning Act applications. The NSIP BNG regime operates under separate secondary legislation and is not directly affected [1] [9].

Q: How recent do baseline ecological surveys need to be for a DCO application?
Survey data is generally considered current if it is no more than two years old at the point of DCO submission. For applications planned for late 2026 or 2027, surveys conducted now (August 2026) will remain valid through 2028, giving adequate headroom.

Q: What is a biodiversity gain statement for an NSIP?
A biodiversity gain statement is the formal document submitted as part of a DCO application that sets out the pre-development biodiversity value, the post-development biodiversity value, and how the 10% gain objective will be met. Sector-specific templates and guidance were published in June 2026 [6].

Conclusion

The BNG NSIP November 2026 nationally significant infrastructure biodiversity net gain deadline is now less than eleven weeks away. For NSIP promoters with DCO applications in the pipeline, the window to commission baseline surveys, run the statutory metric, and draft biodiversity gain statements is closing fast. The regime is unambiguous: applications submitted from 2 November 2026 must demonstrate 10% net gain, with requirements written into the DCO from the outset.

Actionable next steps for project teams:

1. Confirm whether your DCO application will be submitted before or after 2 November 2026, and plan accordingly.
2. Commission or update Phase 1 habitat surveys immediately if submission is planned after the deadline.
3. Run the statutory biodiversity metric to identify your on-site gain potential and residual deficit.
4. Engage off-site unit suppliers early, particularly for large linear infrastructure projects.
5. Use the June 2026 sector-specific biodiversity gain statement guidance from the Planning Inspectorate to structure your submission.
6. Do not assume August 2026 amendments to the standard BNG regime apply to your NSIP without legal confirmation.

For further guidance on achieving biodiversity net gain without the risk and how to achieve 10% biodiversity net gain, the resources at Biodiversity Surveyors provide practical support for project teams at every stage.

References

[1] Biodiversity Net Gain Whats Changing And What It Means For You – https://defraenvironment.blog.gov.uk/2026/04/20/biodiversity-net-gain-whats-changing-and-what-it-means-for-you/

[2] Bng For Nsips Guide – https://www.integratedlm.co.uk/articles/bng-for-nsips-guide

[3] Understanding Biodiversity Net Gain – https://www.gov.uk/guidance/understanding-biodiversity-net-gain

[4] Biodiversity Net Gain Nationally Significant Infrastructure Projects – https://www.gov.uk/government/collections/biodiversity-net-gain-nationally-significant-infrastructure-projects

[5] Statutory Biodiversity Metric Tools And Guides – https://www.gov.uk/government/publications/statutory-biodiversity-metric-tools-and-guides

[6] Biodiversity Gain Statements For Nationally Significant Infrastructure Projects – https://www.gov.uk/government/collections/biodiversity-gain-statements-for-nationally-significant-infrastructure-projects

[7] Biodiversity Net Gain Requirements Extended Nov 2026 – https://www.pinsentmasons.com/out-law/news/biodiversity-net-gain-requirements-extended-nov-2026

[8] Biodiversity Net Gain For Nationally Significant Infrastructure Projects – https://www.gov.uk/government/consultations/biodiversity-net-gain-for-nationally-significant-infrastructure-projects

[9] Infrastructure Planning Blog 53 Biodiversity Net Gain For Nationally Significant Infrastructure Projects And More – https://www.tlt.com/insights-and-events/insight/infrastructure-planning-blog-53-biodiversity-net-gain-for-nationally-significant-infrastructure-projects-and-more

[10] Biodiversity Net Gain – https://www.gov.uk/government/collections/biodiversity-net-gain

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