
Each specific type of NSIP has its own guidance in the form of a Biodiversity Gain Statement published by Defra. These statements outline how the project should measure, deliver and report their BNG. When drafting your requirements for BNG for your DCO they must follow the guidance in the relevant Biodiversity Gain Statement.

Statements are available for the following types of NSIP:
NSIP net gain statements: https://www.gov.uk/government/collections/biodiversity-gain-statements-for-nationally-significant-infrastructure-projects
10% BNG can be delivered in three ways; normally a combination of these options is the most practical. On-site gains mean that the habitats are delivered within the BNG Boundary of the site through enhancing or creating habitats. Off-site gains are habitats that are created or enhanced outside of the BNG boundary. These can be delivered on other land owned by the developer or from a third-party provider (habitat bank). Off-site gains must be registered on the Gain Sites Register and must be allocated to your development site. Both on-site and off-site gains must be maintained for 30 years. Statutory Credits are off-site units provided by the government as a last resort option where it has been proven that all options for on-site and off-site gains have been exhausted.
For NSIPs On-site and Off-site gains are given equal merit and should be considered at the same time. However, the mitigation hierarchy should be followed in that harm should be avoided in the first instance, then losses should be minimised, followed by compensation being provided for any harm caused.
Spatial Risk will be calculated based on the normal multiplier categories. However, where the BNG boundary crosses multiple LPAs or NCAs, these will be considered as inside the same area, therefore providing a larger area to consider for off-site habitats to be created or purchased with no penalty.

To calculate your BNG requirements the Statutory Metric must be used. The metric calculates biodiversity units from types, location, size and condition of habitats. The metric should be used to calculate the baseline and post-intervention biodiversity values of your development. This can then be used to calculate any shortfalls in units to meet the 10% requirement.
When drafting DCO requirements sufficient evidence needs to be provided that the development can meet the 10% BNG requirement. This should include that BNG will be delivered in accordance with the gain plan and subsequent plans or phased gain plans. The evidence in the draft requirements must also set out how shortfalls will be calculated at the final stages and how they will be secured before the project becomes operational.
All on-site gains are considered significant and therefore must be secured as part of your DCO requirements. Alternatively, they can be secured by planning obligation (Section 106) or Conservation Covenant for 30 years. These on-site gains should also be accompanied by a Habitat Management and Monitoring Plan outlining the habitat types, creation works, management, monitoring and maintenance requirements throughout the 30 years. Non-significant gains including baseline habitats being retained or restored habitats do not have to be secured for 30 years. Off-site gains can be secured through the allocation process on the Gain Site Register.
Find out more here: https://www.gov.uk/guidance/enter-a-legal-agreement-for-biodiversity-net-gain.
All BNG must be finalised before the project becomes operational. This entails submitting evidence to the discharging authority by providing evidence that you have met your BNG objectives for the development, including any additional impacts being accounted for in calculations and evidence that all off-site units have been secured.
The developer is responsible for the maintenance of the secured habitats for the 30 years; this includes on-site gains and off-site gains on other land owned by the developer. The 30 years is triggered when the habitat creation and enhancement works are completed, and requires the responsible party to adhere to the maintenance, management and reporting regimes set out in the HMMP.
Biodiversity Net Gain guidance for Nationally Significant Infrastructure Projects published by Defra: https://www.gov.uk/guidance/biodiversity-net-gain-nationally-significant-infrastructure-projects
Guidance on the Pre-Application Stage of a DCO: https://www.gov.uk/guidance/planning-act-2008-guidance-on-preparing-an-application-part-1-pre-application-steps
Guidance on the contents of a draft DCO: https://www.gov.uk/guidance/planning-act-2008-guidance-on-preparing-an-application-part-3-contents-of-a-draft-development-consent-order
