New Carbon Offsetting Requirements for UKGBC Net Zero Carbon Buildings

The UK Green Building Council (UKGBC) recently released their updated document on Renewable Energy Procurement and Carbon Offsetting: Guidance for Net Zero. The guidance was released alongside a webinar explaining the changes made as a response to feedback for the public consultation draft, which was released in late-2020.

The update outlines the pathways for taking a building to net zero carbon for construction and/or operation, and plans are in place to provide support for taking a building to net zero whole life carbon in the future. We have summarised updates relating to net zero carbon construction (embodied carbon).

The guidance for net zero carbon construction can be summarised into three points:

• Measure and reduce construction impacts
• Increase renewable energy supply
• Offset the remaining carbon

Understanding net zero carbon for construction

Net zero carbon construction covers the embodied carbon of the materials and products chosen for the building, in addition to the energy and fuel supply used to extract the items and transport them to site.

A whole life carbon assessment should be carried out for the project to understand the project impact, and efforts should be made to reduce the embodied carbon of the construction. In fact, it is important that carbon reductions are made, before using carbon offsets to bring the residual embodied carbon down to net zero carbon.

Once the embodied carbon has been reduced as much as possible, the use of verified carbon offset credits is the final step to achieve net zero carbon construction.

So what carbon offset credits can be used, in line with the UKGBC net zero carbon framework?

Carbon offsetting for net zero carbon construction

Net zero carbon buildings can only offset through approved carbon offsetting standards. These can be used to offset any remaining carbon emissions associated with the construction of the building. The approved standards are:

• Gold Standard
• Verified Carbon Standard (VCS)
• Clean Development Mechanism (CDM)
• UK Woodland Carbon Code (UK WCC)
• UK Peatland Code

However, as is often the case with carbon offsets, it’s not quite that simple.

Currently, the significant majority of credits under the UK Woodland Code cannot be used for carbon neutrality. This is because there are two different types of carbon credits, as described below.

Carbon credits for net zero carbon

It is important to understand the two types of carbon credits: ex-post and ex-ante. The difference between the credits depends on the timing of when the carbon sequestration has taken place.

Ex-post credits

• These credits correspond to carbon offsets which have already occurred in the past

Ex-ante credits

• These credits correspond to future emissions reductions (I.e., a forest is planted, and emissions reductions will occur in the years after, as the trees grow and sequester carbon)

It should be noted that only verified ex-post credits can be used to offset residual emissions with the UK Woodland Code. This effectively means that UK Woodland Code credits can only be used for very small offset projects. They are unlikely to be available in enough supply to offset the embodied carbon of a building, as discussed below.

Most tree planting projects work with carbon which will be offset in the future (ex-ante) as the trees grow and sequester carbon, with a smaller number of carbon credits coming from carbon sequestration which has already happened (ex-post).

The approach of only allowing ex-post carbon credits is in line with best practice. There is a standard on carbon neutrality, PAS 2060 from the British Standards Institution (BSI). PAS 2060 does not allow the use of ex-ante credits for carbon neutrality – the emission reductions must be verified, meaning they must have already occurred.

UK Woodland Carbon Code for net zero carbon buildings

In theory, UK Woodland Carbon Code credits can be used for offsetting net zero carbon construction projects. However, there are currently just 800 UK WCC credits which are ex-post (<1% of the 1,048,800 available units).

One credit is equal to 1tCO2. Therefore only 800 tonnes of CO₂ is currently available as ex-post UK WCC credits. These are the only credits that are in accordance with the UKGBC net zero carbon framework and the standard PAS 2060.

This means that if a project wants to be 100% net zero carbon for construction using only UK WCC credits, it is theoretically possible, but only if the amount of carbon that is needed to be offset is under the number of available credits. In practice, this is highly unlikely. The use of other carbon offset schemes would be required, such as Gold Standard or VCS.

Use of Carbon Offsets: Twinning Updates

The public consultation draft originally stated that UK Woodland Carbon Code credits had to be twinned with another carbon offsetting credit. This would have meant that if a project needed to offset 10tCO₂, it would offset 10 tonnes with UK Woodland Carbon Code and an additional 10 tonnes with another approved standard.

This has since been omitted due to feedback and is no longer part of the UKGBC guidelines for offsetting credits. Therefore, UK Woodland Code credits no longer need to be twinned with additional credits.

Future guidance

The UKGBC are continuing the work on net zero carbon building guidance, and further work for a net zero whole life carbon roadmap will be developed in the future.

Carbon offsets for net zero carbon construction

Circular Ecology offer carbon credits for various offsetting projects which provide wider benefits beyond carbon sequestration, in line with the UN Sustainable Development Goals.

Carbon credits from these offsetting projects are verified by Gold Standard and/or the Verified Carbon Standard. These certification schemes ensure that the credits are high quality and verified. These credits offer wider environmental, social, and economic benefits, as a result of the project.

If you would like to find out more about the offsetting projects we offer and how you can offset your emissions for net zero carbon construction, please contact us.