Biodiversity Net Gain seeks to benefit nature and brings extra costs for home builders

There are two ways of doing this. The first is on-site BNG, which creates and enhances habitats within the development site. If this is not possible, the second option on the table is off-site BNG, which means buying biodiversity units from landowners who have created or enhanced habitats in the local area. The cost can range from £42,000 to £650,000 for a credit.

Biodiversity Net Gain has been mandatory for major developments since February 12 this year. This includes residential projects with ten or more houses, and commercial buildings with more than 1,000 square metres of floor space.

BNG became mandatory for small developments from April 2 this year. This includes residential developments with nine houses or fewer and developments on less than a hectare of land.

Overall it requires developers to show that the construction will improve biodiversity by at least 10 per cent over 30 years.

There are exemptions and these include small-scale self-builds and self-builds of up to nine dwellings on a site of 0.5 hectares or less. Most extensions are also excluded.

Our reader is correct in thinking that a significant number of people are likely to be unaware of Biodiversity Net Gain and the potential costs involved. The large developers are already au-fait with it but some small builders and homeowners with land or super size gardens are not.

In the case of our reader, they did everything right involving the usual experts, including an architectural technician who thought there would be no problem in getting planning approval, not least because there was still a generous amount of land left for green space on the site.

So they were shocked when their local authority said they had to comply with biodiversity net gain requirements, which would include a significant extra cost, including an ecology report, the price of which is rising due to supply and demand. Expect to pay from £600 to £1,200.

While biodiversity netgain is a laudable idea in principle, other issues have been flagged, not least the buying of biodiversity units on other land, including farmland and forests to offset the loss of green space on building sites. It is not unheard of for large developers to pay £100,000 for BNG credits.

Non-profit organisations, government, landowners and companies that have a primary goal of conserving or restoring land generate a supply of credits, or “certificates,” which developers can buy.

The number of credits you need is worked out from the information you input into the statutory biodiversity metric calculation tool. This is an estimate only and you will need to discuss your potential credit requirements with the local planning authority.

There are more details on the scheme on the government’s website, which cites this example: A developer cuts down some trees on the site where building will take place. They must make up for this impact on the habitat, as well as delivering 10 per cent biodiversity net gain.

They must also do a survey of habitat before development and use the statutory biodiversity metric to explore options. This tells them how to make up for the loss of the trees and what more they need to do to achieve 10 per cent BNG.If they cannot achieve the 10 per cent BNG by creating and enhancing on-site habitats, they must buy off-site units.

While BNG is regulated by a number of bodies, including local authorities and government agencies, regulators are short on staff to ensure that the benefits to habitat materialise.

A study found that some biodeversity net gain sites are at risk of having no increase in biodiversity as there are too few ecologists to regulate and monitor progress or lack of it.

Friends of the Earth have said that BNG is no substitute for lasting changes in business and industrial practices and for proper investment in proven nature conservation action to reverse the decline of nature and natural ecosystems.”

www.gov.uk/government/collections/biodiversity-net-gain for more details.