Embodied Carbon

Policy NZ.3 Embodied Carbon All development proposals should strive to reduce embodied carbon as far as possible. Towards this aim, the following expectations should be met: a. Where it is proposed to demolish a building of 100m2 or more, this should be justified e.g. in relation to feasibility, suitability for the proposed use, or unacceptably poor energy efficiency. b. Major new-build proposals (10+ homes or 1000m2 floor space) should identify the steps taken to reduce the building or overall development’s impact on embodied carbon e.g. regarding its design and building materials to minimise embodied carbon. c. Proposals for large scale new-build developments (a minimum of 100 dwellings or a minimum of 5000m2 of non-residential floor space) must submit a calculation, following the RICS Whole Life Carbon methodology, which should demonstrate that the following targets have been met: ‘Upfront’ embodied carbon emissions (RICS modules A1-A5) • Houses: 600kgCO2 e/m2 floor space (gross internal area). • Flats/apartments: 500kgCO2 e/ m2 floor space (gross internal area) • Non-Residential: 600kgCO2 e/ m2 floor space (gross internal area). Policy Justification 6.1.10 Embodied carbon is the carbon emissions associated with the construction, maintenance and end-of-life of a building. Embodied carbon represents about 25-75% of the total carbon emissions that are caused across a building’s whole lifetime (with the remainder represented by the carbon emissions from energy use in the building). 6.1.11 Up-front embodied carbon is all the emissions that occur up to the point of completing the building, such as due to raw material extraction, manufacturing of construction products, transporting those products to site and the process of construction itself. 6.1.12 Materials like cement, steel and bricks are associated with high embodied carbon emissions (especially up-front embodied carbon) due to their energy-intensive manufacturing. By contrast, recycled materials and bio-based materials like timber and hemp have much lower embodied carbon. Developers of any size of project are encouraged to educate themselves on this topic and are able to give narrative on choices made to make such swaps in their chosen materials. Buildings’ structural design can also help to minimise the necessary total amount of material and therefore embodied carbon. 6.1.13 The RICS Whole Life Carbon Assessment methodology, which follows the relevant British/European Standard (BS15978), is the industry’s accepted method for accounting for embodied carbon. It defines a series of ‘modules’ from A to C. Modules A1 to A5 are the ‘upfront’ embodied carbon. An embodied carbon assessor follows this method while utilising one of several available online databases of embodied carbon emissions of various construction products and methods. These offer embodied carbon information for many specific products and for generic types of typical construction materials/techniques. At the time of drafting this plan, the RICS method is the only acceptable one. However, should alternative methods arise over the plan’s lifetime, these may be considered on their merits. 6.1.14 The Local Planning Authority recognises that an embodied carbon assessment itself can be a significant investment in time and professional fees. This is why the policy only requires that assessment in super-major developments (here defined as 100+ homes or 5,000m2 floor space), because the burden of the assessment itself is much smaller in proportion to the overall project size. Additionally, developments of 100+ homes tend to be made up of repetitions of a small number of home types by volume developers – so that not every individual home needs its own assessment, but a single assessment can cover all homes of the same type. Many leading volume housebuilders have already begun investigating the embodied carbon of their homes20 as part of their wider corporate sustainability efforts such as science-based carbon targets or mandatory carbon reporting and therefore are well prepared to conduct such an assessment, compared to smaller developers. Large non-residential developers are 20 For example: • Bellway BetterWithBellway_October_2024artworked_v5.pdf • Barratt Redrow Achieving Net Zero – Barratt Redrow plc • Persimmon Our Approach | • Cala Science Based Targets initiative | Cala Homes • Vistry Group Vistry Group - Sustainability Report 2023 • Taylor Wimpey Committed to Net Zero ‧ Taylor Wimpey similarly likely to be more familiar with embodied carbon for similar reasons, and because embodied carbon improvements can help earn a BREEAM rating, which is a very widely sought-after certification in the non-residential property market. 6.1.15 The policy only sets targets for up-front embodied carbon, not whole-life carbon. This is because the other parts of whole-life carbon are in the future and the calculation of these emissions is based on less reliable assumptions than the up-front portion. Again, these are only applied to super-major developments in light of their increased ability to take on the reporting burden. 6.1.16 The expectation on smaller developers is merely to educate themselves with regards to the embodied carbon impact of their and material choices, and provide narrative as to the choices they have made in light of this. This expectation still only applies to ‘major’ development and therefore will not put any burden on very small developers and householder applications. 6.1.17 The Local Planning Authority l is aware that new buildings will need additional insulation and equipment in order to meet the separate operational energy targets expressed in policies NZ.1 and NZ.2, and that this therefore could raise the upfront embodied carbon compared to a new build that just meets today’s building regulations. Therefore, the upfront embodied carbon targets expressed in this policy reflect the figures that would be achieved by new buildings that already meet the net zero energy performance standard, as demonstrated in recent published third-party embodied carbon modelling evidence which used the RICS method and covered several types of residential and non-residential building. 6.1.18 Existing buildings represent a significant ‘investment’ in historic embodied carbon. If demolished, that ‘investment’ is wasted and more embodied carbon will be emitted to replace that floorspace. Therefore, policy point 1 is designed to encourage the reu