What NSIPs Are and What's Changing in 2026
If you work on large energy, transport, water or waste schemes in England, you'll have come across the term "Nationally Significant Infrastructure Project" (NSIP). From 2 November 2026, NSIPs face a major change: Biodiversity Net Gain (BNG) becomes a mandatory part of getting a project consented.
This guide sets out what an NSIP is, which sectors are covered, what the new BNG requirement means in practice, and what developers and their teams need to do to prepare.
"Mandatory BNG for NSIPs isn't just a new box to tick, it's a 10% biodiversity commitment that has to be calculated, planned, secured and monitored for 30 years, and then explained clearly to decision-makers, communities and investors."
What Is an NSIP?
A Nationally Significant Infrastructure Project is a large-scale development in England that meets statutory size or capacity thresholds set out in the Planning Act 2008. Rather than going through a local authority planning application, NSIPs are consented through a single Development Consent Order (DCO), examined by the Planning Inspectorate and decided by the relevant Secretary of State against national policy statements.
This route exists because projects of this scale, a new offshore wind farm, a strategic road scheme, a reservoir etc., cross local authority boundaries and carry national significance. A DCO can bundle together consents that would otherwise need to be sought separately (planning permission, compulsory purchase powers, listed building consent, and more) into one process.
Which Sectors Does the NSIP Regime Cover?
The Planning Act 2008 sets out five broad sectors. A project only becomes an NSIP if it meets the specific threshold for its category, eg. size, capacity or generating output.
- Energy — onshore generating stations above 50 megawatts, offshore generating stations above 100 megawatts, electric lines and major energy infrastructure.
- Transport — strategic roads and trunk roads, new railway lines, rail freight interchanges over 60 hectares, large harbours, and airports capable of handling at least 10 million passengers a year.
- Water — large reservoirs and water transfer schemes.
- Waste water — major wastewater treatment infrastructure.
- Waste — hazardous waste facilities and other large-scale waste infrastructure.
Since 2013, a further route also allows certain business and commercial projects to be brought into the NSIP regime by direction of the Secretary of State. Wales operates its own, separate Developments of National Significance regime; Scotland and Northern Ireland use different consenting routes entirely.
Are you preparing an NSIP application for the new BNG requirement?
Get in touch with The Ruby Cube to talk through how visualisation can support your biodiversity gain plan.
- Tel:0203 286 7661
- Email:hello@therubycube.com
What's Changing: Mandatory BNG for NSIPs from 2 November 2026
Biodiversity Net Gain already applies to most development consented under the Town and Country Planning Act 1990. NSIPs have been the major exception, until now. Following a government consultation and confirmation in April 2026, the Environment Act 2021 (Commencement No 11) Regulations 2026 and accompanying biodiversity gain statements were laid in May and June 2026, formally confirming go-live.
- From 2 November 2026, any DCO application submitted on or after that date must deliver a minimum 10% biodiversity net gain.
- The requirement applies uniformly across all NSIP types, the government has ruled out sector-specific exemptions or voluntary approaches.
- The "BNG boundary" is narrower than the full DCO order limits: it covers only habitats that are negatively impacted (temporarily or permanently) by the development, plus any habitats within the order limits used to contribute towards the gain.
- NSIP promoters will be required to submit a biodiversity gain plan alongside their DCO application, including the completed Statutory Biodiversity Metric calculation and confirmation of how a suitably qualified ecologist contributed to it.
- All significant on-site and off-site gains must be legally secured, with robust long-term monitoring commitments, consistent with the 30-year timeframe already familiar from the TCPA regime.
- The requirement does not apply retrospectively to changes made to a DCO where the original application predates mandatory BNG.
What Developers (and Their Teams) Need to Do Now
With go-live confirmed and guidance landing through 2026, the practical groundwork for NSIP promoters, ecologists and planning teams starts well before an application is submitted.
1. Establish an accurate baseline early
Habitat baselines need to be captured using UKHab classification and the Statutory Biodiversity Metric, well ahead of submission. For large, often remote or inaccessible sites, DEFRA LiDAR-derived terrain data can support faster, more defensible baseline mapping across the whole order limits.
2. Build the biodiversity gain plan around a qualified ecologist
The gain plan must set out how a suitably qualified ecologist has contributed to the habitat assessment, the metric calculation, and the ongoing management and monitoring proposals, this needs to be documented, not just implied.
3. Plan for the narrower BNG boundary
Because only impacted or contributing habitats count, teams need to map exactly where within the order limits the 10% gain will be assessed and delivered, and distinguish this clearly from habitat reinstatement, which is treated differently and does not need the same securing mechanism.
4. Decide on-site versus off-site delivery (and secure it)
Off-site gains delivered within the same local authority area or National Character Area as the NSIP will generally avoid the spatial risk multiplier penalty, though this safe harbour does not extend to watercourse units spanning multiple catchments. Whichever route is chosen, gains need a secured legal mechanism, a Section 106 obligation, conservation covenant, or equivalent, and a monitoring plan covering the full commitment period.
5. Communicate the plan to non-specialist decision-makers
A biodiversity gain plan and metric calculation are technical documents. Examiners, the Secretary of State, statutory consultees and local communities engaging with the DCO process are rarely ecologists. Clear terrain visualisation, habitat fly-throughs and before/after renders help translate the metric into something a non-specialist audience can actually evaluate — often making the difference in how confidently a gain plan is received at examination.
"Compliance with the metric gets a project to the table. Being able to show, not just state, what a 10% gain looks like on the ground is what helps it move through examination and secure public confidence."
Timeline at a Glance
2021 - BNG provisions enacted
BNG provisions enacted under the Environment Act 2021, including Schedule 15 inserting Schedule 2A into the Planning Act 2008.
2024 - 10% BNG introduced
Mandatory 10% BNG introduced for development under the Town and Country Planning Act 1990.
April 2026 - mandatory BNG for NSIPs
Government confirms mandatory BNG for NSIPs, ruling out sector exemptions.
May 2026 - Secondary legislation
Secondary legislation (SI 2026/492) laid before Parliament.
November 2026 - 10% BNG applies to all NSIPs
Mandatory 10% BNG applies to all NSIP applications for development consent submitted on or after this date.
How The Ruby Cube Helps NSIP Promoters Communicate BNG effectively
The Ruby Cube specialises in photorealistic environmental visualisation, LiDAR-based terrain generation and habitat fly-throughs for BNG, planning and conservation projects. These are built on deep familiarity with the Statutory Biodiversity Metric and UKHab classification.
As mandatory BNG extends to NSIPs from November 2026, we help developers, ecologists and planning teams turn biodiversity gain plans into visual evidence that examiners, communities and investors can actually understand.
Are you preparing an NSIP application for the new BNG requirement?
Get in touch with The Ruby Cube to talk through how visualisation can support your biodiversity gain plan.
- Tel:0203 286 7661
- Email:hello@therubycube.com
FAQs
Does BNG apply to NSIP applications submitted before 2 November 2026?
No. The mandatory requirement applies to applications for development consent submitted on or after 2 November 2026. Applications submitted before that date are not subject to the new duty, and changes to a DCO originally consented before mandatory BNG applied are also excluded.
Is there a lower BNG percentage or exemption for any NSIP sector?
No. The government has confirmed a single, uniform 10% net gain requirement across all NSIP types, with no sector-specific exemptions and no voluntary alternative route.
Does the BNG boundary cover the whole DCO order limits?
No. It's narrower than that. The boundary covers habitats that are negatively impacted, temporarily or permanently, by the development, along with any habitats within the order limits being used to contribute towards the gain — unaffected habitats elsewhere in the order limits don't need to be included in the baseline.
Who has to sign off the biodiversity gain plan for an NSIP?
The gain plan must confirm how a suitably qualified ecologist has contributed to the plan itself, the Statutory Biodiversity Metric calculation, and the habitat management and monitoring proposals.
How long do NSIP biodiversity gains need to be monitored for?
Monitoring and management commitments align with the existing BNG regime, which requires gains to be secured and maintained over a long-term period — in practice this mirrors the 30-year monitoring horizon already used for TCPA developments.
Regulatory disclaimer (accurate as of 17 August 2026): This article reflects the Environment Act 2021 (Commencement No 11) Regulations 2026 (SI 2026/492), the biodiversity gain statements laid in May–June 2026, and confirmed government policy that mandatory 10% BNG applies to NSIP development consent applications submitted on or after 2 November 2026. Defra guidance continues to be published ahead of go-live and some implementation detail may still evolve. This is not legal advice, always check current Defra and Planning Inspectorate guidance, or seek professional advice, before relying on these details for a live application.
