New study looks at embodied carbon in construction

New study looks at embodied carbon in construction

It has been estimated that approximately 20% of GHG emissions are embodied in the construction sector.

Embodied carbon emissions in construction – commonly referred to as ‘Embodied carbon’ refers to the GHG emissions associated with the manufacturing, maintenance, and decommissioning of a structure.

A new report reviews seven leading examples of countries that have implemented policies and programs that are intended to reduce embodied GHG emissions of buildings and infrastructure projects.(Belgium, France, Germany, The Netherlands, Sweden, Switzerland, and the United Kingdom) Two more examples (Finland and Singapore) that are in the process of development are also examined.

This report was commissioned by Forestry Innovation Investment Ltd. to better understand the approaches by leading countries to addressing embodied carbon and the best practices that could be applied elsewhere.

KEY FINDINGS

  1. Life-cycle perspectives are key to understanding the long-term impacts of construction-related GHG emissions. Many recent climate-change policies reference “net-zero” (either energy or carbon) for buildings. However, a building is not truly “net-zero” until it has paid back or offset its initial carbon debt (i.e., the embodied GHG emissions associated with materials, manufacturing, and other processes that are upstream of building occupancy) and has considered its future carbon emissions in terms of end-of-life decommissioning. Jurisdictions with policies that are driving towards sustainable consumption and production goals or towards a “circular economy” are on the path towards addressing embodied carbon because these policies demonstrate an understanding of the importance of having a life-cycle perspective in order to reduce GHG emissions in absolute terms rather than by merely shifting GHG emissions between life-cycle phases.
  2. An embodied carbon policy tackles GHG emissions reductions not currently being addressed in the context of buildings and infrastructure on the scale and in the time frame required to meet national and/or international GHG emissions reductions commitments. Climate-change policies and programs generally do not account for embodied carbon in buildings and infrastructure despite embodied carbon being an important piece in the overall emissions profile of many jurisdictions. Not only is embodied carbon a significant proportion of a building’s overall carbon footprint, but reductions in embodied carbon are realized in the short term, which is a critical consideration given that global carbon emissions need to be urgently reduced to meet international climate commitments.
  3. In order to reduce embodied carbon in new and existing construction, carbon incentives should be tied to measurable performance outcomes. Proxy measures and prescriptive solutions with a presumed GHG emissions reduction benefit should be replaced by incentives based on quantifiable and comparable results. Prescriptive sustainable design guidelines and incentives simplify decision-making but can limit creative problem-solving and may not deliver actual reductions in environmental impact. Prescriptive strategies also do not allow for design flexibility, are limited in scope, and are not tied to measurable performance outcomes. Whole-building LCA, on the other hand, is an internationally accepted science. It is intended to be used by project teams to quantify embodied carbon and other environmental impacts in buildings, and can be the basis of a life-cycle carbon policy.
  4. Ample precedents of best practices and program design are available for jurisdictions to draw on. The leading international jurisdictions reviewed in this report have explored a variety of approaches, thereby providing helpful test cases for all types of policies and programs— from voluntary reporting to mandatory performance standards. The following countries are taking significant action to reduce embodied carbon in construction, either through regulatory policy or strong incentives:

Action at national level

  • Belgium: Has a national EPD database. Manufacturers wishing to make environmental marketing claims must submit an EPD to the database.
  • France: Offers building labels and incentives for voluntarily meeting both embodied carbon and net-zero energy consumption targets. The voluntary pilot program is expected to become mandatory in 2020. France has a national EPD database. Manufacturers wishing to make environmental marketing claims must submit an EPD to the database. `
  • Germany: Whole-building LCA is required for new federal building projects as part of a green building rating program specific to government projects, with points awarded as a function of performance against a benchmark. A private-sector voluntary green building program has a similar LCA benchmark approach. Germany has a national LCA/EPD database and a free, national, whole-building LCA software tool.
  • The Netherlands: Requires embodied carbon reporting at the building-permitapplication stage for new residential and office buildings over 100 m2 . A building’s total environmental profile (of which embodied carbon is one element) will have an upper limit, based on standardized weighting factors, as of 2018. The Netherlands also has a national EPD database, a standardized method for whole-building LCA, and several software tools that conform to the standardized method.
  • Sweden: Large transportation infrastructure projects are required to calculate and report embodied carbon. There are incentives to reduce the embodied carbon below a target. Sweden has a national LCA-based tool to support its program.
  • Switzerland: Whole-building LCA is required for all new government buildings in several municipalities, including Zurich, with an embodied carbon performance target for some building types. Switzerland has a national call-to-action (the “2000 Watt Society”) to limit per-capita energy consumption and all GHG emissions, including embodied GHG emissions.
  • United Kingdom: Voluntary green building rating programs have long included LCA, with increasing sophistication as the programs have been updated. Embodied carbon performance targets are now in place in a residential program and are anticipated in 2018 for a commercial/institutional program.
  • Download study here
April 24, 2018
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