The UK Net Zero Carbon Buildings Standard Guide: Part 11: Carbon offsetting

13 Dec 2024

The pilot version of the UK Net Zero Carbon Buildings Standard (the Standard) was published in September 2024. The full document can be downloaded here. The Standard has been produced by a range of industry professional organisations including RIBA (architecture), IStructE (structural engineering), CIBSE (services engineers) and RICS (surveyors), along with a large team of other industry organisations and professionals.

It aims to set out unambiguously, for a wide range of scenarios, the characteristics that buildings and building projects need to be aligned with the UK’s strategy to become net zero carbon by 2050. The Standard builds upon and supersedes previously published approaches such as the UKGBC Net Zero Carbon Building Framework, the RIBA Climate Challenge and the various LETI design guides.

Read more from our guide:

Part 1: Key principles and overview

Part 2: Embodied carbon

Part 3: Operational energy

Part 4: On-Site renewable generation

Part 5: Operational Water Use

Part 6: Fossil fuel free

Part 7: Electricity demand management

Part 8: District heating and cooling networks

Part 9: Space heating and cooling

Part 10: Refrigerants

Part 11: Carbon offsetting

Carbon offsetting requirements

The pilot version of the standard does not require any carbon offsetting for a building to be net zero carbon aligned. However, there is an option to include offsetting for the building to be considered net zero carbon aligned (with offsets). The offsets would apply for all up-front and in-use emissions associated with the development, namely the following:

Upfront carbon emissions due to New or Retrofit Works
Upfront carbon emissions due to Reportable Works
Operational energy use carbon emissions
Operational water use carbon emissions
Carbon impact of refrigerant leakage – Kyoto products only

Offset option one: carbon credits

If a development does decide to follow the offsetting route, purchased carbon credits must meet either of the following standards:

The ICROA endorsed voluntary carbon market standards and their Code of Best Practice
The ICVCM principle labelled credits (new programme, no credits available at release of the NZCBS Pilot) and their Core Carbon Principles

Additionally, the carbon credit must adhere to the following:

The vintage (year) of the credits must be no more than five years outside of the Reporting Period End Point
Credits must be purchased and retired specifically for the in-scope carbon emissions

Offset option two: renewable energy procurement

For offsetting Scope 2 emissions only, a development can also go down the route of Renewable Energy Procurement. Three routes can be followed for this:

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Comments on the proposals

Aspects we think will work well

We agree with the decision to make carbon offsetting optional. Carbon offsetting should be a last-resort solution due to significant challenges in ensuring its effectiveness and fairness. The quality of carbon credits is often questionable, with misleading claims, inflated conservation successes, and insufficient self-regulation. Additionally, many projects have harmed local communities and Indigenous peoples, sometimes forcibly displacing them from their land.
We believe that by not making offsetting mandatory, this may help with some of the cost barriers to achieving net zero carbon, which is often a major hurdle for smaller projects.
The guidance to comply with requirements for offsets is a lot more clear than with the UKGBC Net Zero Carbon Standard, thereby increasing the uptake of offsetting

Aspects recommended be considered for further development

The standard is quite clear on what is allowed in terms of offset and renewable energy procurement; however we believe there could be more guidance around the cost of offsetting and how much projects need to spend per tonne of carbon

Reporting metric

For the submission, projects going down the net zero carbon aligned (with offsets) route will need to include information on the quantity of carbon credits and renewable energy procured as well as details and a written statement detailing how they meet the requirements detailed above. This should include the following information:

The type, supplier, vintage, and registry reference of carbon credits;
The renewable energy tariff or contract agreement with the supplier if using renewable energy procurement;
Proof of procurement and retirement of the carbon credits.

Example from our projects

As a practice, we do not offer a service for offsetting, however we have worked on a few projects in which offsetting was used to achieve net zero carbon in compliance with the old UKGBC NZC Framework. One of these is the Max Fordham House, which used both renewable energy procurement and carbon credits in the offsetting strategy. The building is all-electric, so carbon credits were used to offset the upfront carbon only (102tCO₂e) and renewable energy is used to offset carbon associated with the operational energy use.

Carbon credits: A price of £70 per tonne of CO2e was agreed upon and this was used to purchase a mixture of Gold Standard Offset Verified Emission Reduction units.
Renewable energy procurement: 100% of the building energy is supplied by renewable energy, with 76% of this being grid imported “High Quality Green Tariff” through the Good Energy Standard Tariff.

A full breakdown of the Carbon Credit budget can be seen below, and you can read more about this project and the offsets purchased.

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Max Fordham House

Total of 2 images

View of the kitchen with neat white cupboards and rooflights — © Tim Crocker

Exterior of Max Fordham House. A modern mews house covered in ivy. — © Tim Crocker