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Whole Life-Cycle Carbon: a roadmap

Sustainability energy tree. Photo: pixabay

The London Plan will be with us soon. As part of that, the Greater London Authority (GLA) released Whole Life-Cycle Carbon (WLC) Assessments guidance in April, which will be consulted upon formally once the Plan is approved.

As you would expect, a wide range of stakeholders has been consulted, including developers, industry and technical experts. The draft sets out a requirement for developments to calculate and reduce WLC emissions.

The context is that Sadiq Khan, the Mayor of London, has declared a climate emergency and set the ambition of London being net zero-carbon.

What are WLC emissions?

They are the carbon emissions that result from the combination of the materials, construction and use of a building throughout its life and afterlife, effectively, as demolition and disposal form part of the cycle.

The approach considers operational (both regulated and unregulated) and embodied emissions in tandem over a project’s life cycle, and determines the best opportunities to reduce lifetime emissions.

This dual approach, which pays attention to the carbon intensity of the structure itself as well as to reducing its operational energy, is part of the relatively recent move away from simply focusing on operational emissions alone. The RICS guidance uses the following example to illustrate the potential pitfalls of focussing solely on the operational side:

“The embodied carbon burden of installing triple glazing rather than double can be greater than the operational benefit resulting from the additional pane.”

The integration of these two elements needs to be understood as part of the sustainability agenda and the imperative of working towards a low carbon future.

What’s in the guidance?

The document covers three principal areas:

  • Aims, benefits and targets
  • Process and methodology
  • Assessment content

Let’s consider each of these in more detail.

Aims, benefits and targets

An overarching aim is the London Plan net-zero carbon target for all major developments, with the GLA supplying Energy Assessment Guidance on how to achieve this. Furthermore, major developments must be seen to be doing this through transparent monitoring and reporting. All referable planning applications must calculate and reduce WLC emissions.

There are manifold benefits listed in the guidance, including:

  • Ensuring that the built environment contributes to achieving the net-zero carbon city
  • Achieving resource efficiency and cost savings by encouraging the re-use of existing materials and the retrofit and retention of existing structures and fabric
  • Identifying the carbon benefits of using recycled material and of designing for future reuse and recycling to reduce waste and support the circular economy
  • Encouraging a ‘fabric first’ approach to building design thereby minimising mechanical plant and services in favour of natural ventilation
  • Considering operational and embodied emissions simultaneously to identify the best solutions for the development over its lifetime
  • Identifying the impact of maintenance, repair and replacement over a building’s life-cycle which improves life-time resource efficiency and reduces life-cycle costs, contributing to the future proofing of asset value
  • Encouraging local sourcing of materials and short supply chains, with resulting carbon, social and economic benefits for the local economy
  • Encouraging durable construction and flexible design to contribute to greater longevity, reduce obsolescence of buildings and avoid carbon emissions associated with demolition and new construction

Other documents submitted at planning may have an impact upon the WLC assessment, such as Environmental Impact Assessments, Design and Access Statements, Sustainability Statements and Resource Management Plans.

Process and methodology

WLC Assessments are required at three stages: pre-application; stage 1 submission (RIBA stage 2/3) and post-construction (RIBA stage 6). They must be carried out using a nationally recognised assessment methodology. Actions to reduce emissions must be demonstrated.

The assessment needs to cover operational, embodied and post ‘end of life’ benefits. All this must be done under the appropriate framework BS EN 15978 and be underpinned by the RICS Professional Statement: Whole Life Carbon assessment, which functions as the methodology here.

Both BS EN 15978 and the RICS PS set out for four stages in the life of a project, which are known as life-cycle modules, and which must be presented discretely, based on a period of 60 years:

  • Product sourcing and construction: to reduce carbon emissions both at this stage and the subsequent ones. Processes in fabricating products and methods of construction are important.
  • Use: to understand how the building will perform, to minimise future emissions from maintenance, repair and replacement, and to minimise operational energy use via due consideration of the building’s overall resource efficiency
  • End of life: to capture the emissions from deconstruction and demolition, transport, waste processing for reuse, recovery or recycling and disposal, until the site is cleared, level and ready for further use
  • Benefits and loads beyond the system boundary: to develop scenarios regarding what will happen to a building after it has been demolished or dismantled in order to facilitate future reuse, recycling or recovery. This and the previous module together form the circular economy module

Materials, products and grid carbonisation are considered in the remainder of this section.

Assessment content

A WLC assessment template has been constructed, which gives applicants all the required information for submission at each of the three stages. Throughout this section, and indeed the whole document, user-friendly diagrams and tables are employed to aid applicants during the process.

For example, the Principles for reducing WLC emissions lists sixteen areas to be considered, with each having a separate list of relevant modules to which it pertains. They form a one stop shop for emission reduction.

Furthermore, headline information is given in this section, as is a note regarding software tools, which are listed in one of the three appendices. The three stages are explained in easy to follow steps.

As applicants will want to understand the process, transparency is assured via a list of what will be scrutinised in the assessments.

This assessment is an important step in emission reduction. For context, the World Green Building Council estimates that globally construction is responsible for 11% of carbon emissions.

London, as one of the world’s great cities, clearly has an important role to play in recusing carbon emissions and moving in the direction of the required environmental targets. Transparent and rigorous guidance like this can only push the city and the rest of the UK in the right direction.