Key Takeaways:
- BNG will apply to NSIPs from May 2026, bringing new legal requirements, larger-scale biodiversity delivery, and a shift in how infrastructure projects are planned and approved.
- NSIPs will require far greater numbers of BNG units, with most unable to deliver gains on-site. Developers will need to source large quantities of off-site units through verified sellers to stay compliant.
- The BNG market is about to reshape, with NSIPs becoming the largest buyers of biodiversity units in England, driving early engagement, smart sourcing, and nature restoration at scale.
As of February 2024, mandatory BNG has become a key part of the Town and Country Planning system, following updates to the Country Planning Act.
From April 2024 and reinforced by changes on 24 July 2025, most new developments must deliver measurable biodiversity gains, enhancing biodiversity value and protecting irreplaceable habitats through approved biodiversity gain sites.
A crucial change on the horizon is the inclusion of NSIPs under the Biodiversity Net Gain policy, bringing in unparalleled demand for BNG units across England, reshaping the market, and fuelling nature restoration at scale.
Our latest article delves into the upcoming change, with advice, explainers, and insights on how developers, ecologists, landowners and more can prepare.
What Are Nationally Significant Infrastructure Projects (NSIPs)?
While most developments already require Biodiversity Net Gain (BNG) as part of planning permission, NSIPs will soon follow under their own national framework.
Nationally Significant Infrastructure Projects (NSIPs) are new major infrastructure developments.
Outlined first in the Planning Act 2008, the regime became fully in force in 2010.
The hundreds of pre-2008 infrastructure schemes did not become NSIPs, and ones under the new title gain national recognition, streamlined consent, and new land powers.
NSIPs aren’t just any major infrastructure projects, they must be:
- Energy – generating stations over 50 MW onshore or 100 MW offshore, plus large electricity lines, gas storage, LNG terminals, and national oil or CO₂ pipelines.
- Transport – strategic national roads, railways, ports, or airports (airports handling at least 10 million passengers a year).
- Water – very large reservoirs or water transfer schemes meeting statutory capacity thresholds.
- Wastewater – treatment works serving a population equivalent of 500,000 people or more.
- Waste – facilities handling at least 100,000 tonnes of waste per year.
Other projects may be deemed NSIPs by the Secretary of State (the planning side), such as large commercial developments, science/tech campuses, energy transition projects, or cross-sector schemes.
Applying mostly in England and Wales (with Scotland and Northern Ireland using separate systems), there could be an estimated 10-20 new NSIPs a year.
It’s likely that more NSIPs will be needed in the coming years, as the UK continues its energy transition, adapts to climate change, experiences population and economic growth, and faces increasing housing demand.
When Will BNG Apply to NSIPs?
Biodiversity Net Gain (BNG) is proposed to apply to NSIPs from May 2026, just half a year away, so the time to plan is now.
It was meant to be mandatory for NSIPs from November 2025. This was announced on the 29th November 2023, just a proposed introduction date.
DEFRA (Department for Environment, Food and Rural Affairs) then went on to update the guidance on 26th June 2025, pushing it to May next year.
This was due to several reasons:
- Complexity of NSIPs requiring bespoke frameworks
- Further development of detailed metrics and guidance
- Additional time to incorporate stakeholder feedback properly
- Better alignment with ongoing infrastructure planning processes.
DEFRA’s 2025 consultation is still collecting responses from authorities, environmental groups, and developers to sharpen the future delivery.
Consultation results (an official government response) are expected late 2025, with final rules and guidance for how it will apply. Secondary legislation will be laid before Parliament to bring into law formally.
How Will BNG Requirements Differ for NSIPs?
There are key differences between normal and NSIP BNG requirements due to an NSIP’s sheer scale, complexity and breadth.
Disregarding the countless policy-specific inconsistencies, the main categories of change are:
- Legals and consent – normally through LPAs (Local Planning Authorities) and RBs (Responsible Bodies), but NSIPs will have to secure BNG through longer and more formal DCOs (Development Consent Orders)
- Delivery approach – normally delivered after construction, but NSIPs can be phased (so in stages that align with a project’s construction schedule)
- Scope and coverage – normally applies to most major developments, but for NSIPs, only covers onshore projects in England
- Timing and transition – already mandatory, but for NSIPs it starts in May 2026.
Only onshore NSIPs are being covered for BNG as offshore projects will fall under Marine Net Gain, a policy coming in further years.
Beyond the general differences, a key change impacting the BNG market will be the number of units required. At present, most developers require only small fractions of a unit, with rarer but frequent larger needs.
Covering hundreds to thousands of hectares, NSIPs will require far greater numbers of BNG units: potentially more than 1,000 biodiversity units just for one project which itself equates to a rough £30 million.
The BNG market is about to shift significantly, with NSIPs set to become the most significant purchasers of BNG units.
The Legal Framework: Planning Act 2008 and Schedule 2A
The Planning Act 2008 is a law that sets up a national planning system for huge infrastructure projects.
Under this act, projects don’t go through councils (LPAs), but through a streamlined national process at a higher level.
Schedule 2A is an extra section added later alongside the new Environment Act 2021, adding the BNG rules to NSIPs.
Importantly, the extra section:
- Defines the BNG objectives for NSIPs to meet the 10% gain
- Allows the Secretary of State (the DEFRA side) to make further rules
- Outlines BNG statements and plans
- Aligns with the existing DCO process.
They together form the backbone for BNG to work for NSIPs within the national infrastructure planning system.
Biodiversity Gain Statements for NSIPs
The Biodiversity Gain Statement will be the official rulebook for how BNG will apply to NSIPs.
It’s not out yet, and will likely come after the consultation results, shaped by responses and feedback. DEFRA will publish the official statement ahead of the May 2026 date.
It will be the single most important document for making BNG apply legally to NSIPs, defining:
- exactly how to measure it (with a shiny new NSIP biodiversity metric),
- which NSIPs must deliver the gain,
- which are exempt,
- and which evidence developers must put into their DCO applications (e.g. habitat surveys, HMMPs, etc.).
When the statement comes out, industries can start preparations with certainty. Ecologists might start forming NSIP-specific surveys, BNG sellers may scour for upcoming local NSIPs, and everyone can use the Gaia BNG Marketplace to find and trade BNG units at the best value.
Measuring BNG in the NSIP Context
BNG for NSIPs will be measured similarly to the normal policy, but with an NSIP-specific metric.
This will become clearer when the BNG consultation results are released, as well as the subsequent Biodiversity Gain Statement.
It’s very likely that it will follow the same measurements as normal BNG of Area, Hedgerow and Watercourse primary unit types, with trading rules from Very Low to Very High distinctiveness.
The metric, however, will be adapted for linear and larger projects accounting for phased assessments, temporary land uses, multi-site flexibility and linear route handling.
On-Site vs Off-Site Delivery for NSIPs
For NSIPs, achieving Biodiversity Net Gain on-site is unlikely, so most projects will need to rely on the off-site market to deliver the required 10% gain.
This is because NSIPS will require a significant number of biodiversity units, which equates to a lot of space.
This usually won’t work on-site because:
- Land is fully used for infrastructure
- Areas are linear and spread out
- They have safety and engineering limits.
In that case, developers will have to look to purchase BNG units off-site. This is where Gaia comes in, the largest BNG Marketplace in the UK with over 44,000 biodiversity units with a total value of over £1.2 billion.
Powered by an extensive network of BNG sellers from the RSPB, Environment Bank, Wildlife Trusts, local planning authorities and more, Gaia is the number one platform for sourcing biodiversity units.
It’s free to browse and send unlimited enquiries, so developers can reach out to local sellers in the earliest stages, compare quotes, and secure the best value for projects.
Land Acquisition and Compulsory Purchase Considerations
While the government has acknowledged that CPOs (Compulsory Purchase Orders) might be available for NSIPs to purchase land and offset directly onto, this remains uncertain.
This is because it could affect the growing BNG market, which has encouraged private landowners to sell habitats for offsetting developers.
We’ll know more when the Biodiversity Gain Statement is published, but even if CPOs are permitted, they are expected to be used only in limited circumstances.
CPOs can take 18–24 months to complete. Purchasing pre-established habitat banks would likely be quicker, simpler, and less contentious.
BNG Reporting and Monitoring for DCO Applications
Just like normal BNG, NSIP developers will have to continuously prove their biodiversity commitments with standard monitoring and reporting measures.
This involves a BNG plan document that sets out exactly how the 10% will be achieved, verified, and is legally tied to the DCO.
While in normal BNG the checks are either done (i.e. every year) by the LPA (with a Section 106) or the RB (with a Conservation Covenant), NSIP checks will be conducted through mechanisms set out in the DCO, overseen by the relevant Secretary of State.
Voluntary Adoption of BNG Before the Mandate
There are a few infrastructure bodies exploring how Biodiversity Net Gain might work for NSIPs once it becomes mandatory.
Due to the lack of set regulations, guidance or measurement systems, they’re only testing principles.
For instance, National Highways has been working with Natural England since 2019 to establish no net loss approaches to new developments.
Their partnership is a key evidence source of how BNG will work for them, as they test exactly how the metric would work for wider, more linear projects.
Challenges and Practical Considerations for NSIP Developers
One of the toughest challenges for NSIP developers will be sourcing BNG units that are:
- available in very large quantities
- local to their project area
- the right habitat types and distinctiveness levels
- from verified, trusted sellers
- and with enough choice to compare quotes and find value
In short, NSIPs are about to reshape the BNG landscape.
Clear guidance, early engagement and smart use of tools will be essential to keep projects compliant, efficient and cost-effective.
Government Guidance
Government guidance is in short supply until the official rules are released later in 2025; however this is a useful document to consult in the meantime: Government Guidance on BNG for NSIPs (Defra, May 2025).
Next Steps
As for next steps, NSIP developers should search in their National Character Area (NCA) and Local Planning Authority (LPA) on the Gaia platform. Identify local sellers from the offset, allowing you to secure units and prepare yourself at an early stage.
In the case that supply is missing, Gaia filters allow you to search in a neighbouring LPA / NCA, and find sellers that would happily offer a deal to accommodate the larger NSIP-level unit amount required.
Moreover, you can submit a unit request which Gaia matches across its verified seller network to help you source the right habitats, at the right scale, ahead of schedule.
Under Biodiversity Net Gain, new national infrastructure will leave the environment in a better state than before, and help us restore England’s critical natural resources.
FAQs
When will Biodiversity Net Gain (BNG) become mandatory for NSIPs?
BNG is proposed to apply to NSIPs from May 2026, just half a year away, so the time to plan is now. The official rulebook will be released later this year, following the BNG consultation results.
How will BNG be measured for NSIPs?
BNG for NSIPs will be measured similarly to the normal policy, but with an NSIP-specific metric. It will likely follow the same measurements as normal BNG of Area, Hedgerow and Watercourse unit types, with trading rules from Very Low to Very High distinctiveness.
Can NSIPs achieve BNG on-site?
For NSIPs, achieving BiNG on-site is unlikely, so most projects will need to rely on the off-site market to deliver the required 10% gain. They require a significant amount of BNG units, and land is usually fully used for infrastructure.