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CIBSE and LETI launch industry FAQs on Net Zero Operational Carbon



The Chartered Institution of Building Services Engineers (CIBSE) and London Energy Transformation Initiative (LETI) have launched new guidance on delivering net zero carbon buildings.

The document was launched during a live event on 7 April 2022. 

Catch up with the recording on-demand

Providing the language to facilitate a unified and collaborative transition to net zero, designed to drive real progress by providing clarity on what net zero means for buildings, in practice and in detail, this document is free to download.

Led by Julie Godefroy, Head of Sustainability for CIBSE and Clara Bagenal George, founder of LETI and Associate at Elementa Consulting, and building on definitions from the Whole Life Carbon Network (WLCN) and LETI. The definitions and FAQs cover whole life, embodied – referring to total emissions and removals associated with an asset throughout the whole life cycle of an asset; upfront carbon – referring to emissions associated with materials and construction processes up to practical completion; operational energy; and operational water. Crucially these new definitions are based on meeting operational energy and embodied carbon targets and generating energy from renewable sources.

An industry consultation sought to identify the areas where more clarity was needed. Following this, a set of FAQs and an accompanying survey were developed, seeking industry consensus on technical details and terminology relating to net zero carbon . 

Read summary of the consultation responses

The aim is to see the WLCN-LETI definitions applied consistently and robustly in as many real-life situations as possible. This guidance adds to existing resources from CIBSE and LETI, such as the LETI Climate Emergency Design Guide and CIBSE TM65 Embodied carbon in building services: A calculation methodology to support a collaborative transition to net zero.

These FAQs do not provide a definitive answer to what net zero means, but they provide a direction of approach to address common situations in most building types. CIBSE and LETI are committed to reviewing and adding to these resources, such as energy use and embodied carbon targets. This will include working together and independently, for example for CIBSE, continuing its work on assessing the impact of building services  to feed into industry targets.

This document is a line to mark the start, with additional work being planned in collaboration with other industry bodies to further establish clarity and consensus on net zero.

The results of the survey indicated acceptance that achievements towards net zero carbon should be acknowledged on the basis of actual delivery. For example, in terms of operational energy, this would mean claims are verified annually, using measured energy use and a third party verified assessment. The survey results also reflected support for providing ‘Net Zero In Progress’ status at different project stages and in cases where there are genuine constraints, subject to robust and committed plans to address these constraints: in the FAQs, this is proposed to apply in the case of existing buildings with a retrofit plan, and buildings connected to a non-compliant energy network with a decarbonisation plan.

Julie Godefroy commented;

“There are huge benefits in the whole sector having a common set of definitions as well as guidance on detailed implementation in practice, so all disciplines, clients, investors, and occupants are clear on what is being achieved or aimed at.”

Watch the launch event on-demand now

Find out more about the work that CIBSE is doing around net zero

About LETI
LETI is a network of built environment professionals that are working together to put the UK on the path to a zero carbon future. In 2020, LETI launched the Climate Emergency Design Guide and the Embodied carbon primer, which outlines requirements of new buildings to ensure our climate change targets are met. in 2021, LETI published guidance on Hydrogen, Carbon Alignment, a Client Guide for Net Zero Carbon Buildings and the Climate Emergency Retrofit Guide.

Find out more about LETI

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