Under Construction - Q3 2021 – 5 / 5 观点
Recent headlines on climate change and reduction of CO2 emissions have highlighted the need to de-carbonise homes and buildings, to expand low carbon energy systems and to restore peatlands and plant more trees. A Heat and Buildings Strategy is expected shortly which is likely to include proposals to end the use of gas boilers, and the use of heat pump alternatives. This will be followed by a Hydrogen Strategy focusing on the use of hydrogen as an alternative heat source. These new strategies will build on the work of the Future Homes Standard and the Future Buildings Standard and associated uplifts to Part L (energy) and Part F (ventilation) of the Building Regulations. The intention is to secure reductions in emissions in new homes and new non-domestic buildings, and for these buildings to become zero-carbon ready by 2025.
So far, Government regulation has tended to focus on the operational efficiency of buildings. This was acknowledged in the Sixth Carbon Budget, produced by the Climate Change Committee in December 2020, which highlighted that there are few policies in place to improve resource efficiency or incentivise materials' substitution when constructing buildings or infrastructure. However, achieving net-zero will require renewed focus by the construction industry on embodied carbon, particularly in the context of materials' use and re-use.
There are various sustainability assessment tools, such as BREEAM (a UK based rating system) and LEED (a US green building rating system) which focus on the environmental credentials of buildings. These are not compulsory but are widely used by organisations to ensure a buildings' green credentials. By way of example, BREEAM assessment focuses on sustainable value across a range of categories, one of which is materials' use which is aimed at ensuring that materials are procured in a responsible way and have a low embodied impact over their life, including extraction, processing, manufacturing and re-cycling. CarbonAction 2050, from the Chartered Institute of Buildings, contains a section of guidance on retrofitting and re-use of buildings as a way to maximise the use of an asset's embodied carbon.
In this context, the recommendation from the Sixth Carbon Budget of the development of a standardised approach to calculating the whole-life carbon footprint of buildings makes interesting reading. Mandatory disclosure of whole-life carbon in buildings and the establishment of a mandatory minimum whole-life carbon standard, as proposed in the report, looks to be some way off, with further debate and analysis required, although it could act as a catalyst for de-carbonising construction materials, such as cement and steel. Another area that could be addressed is off-road mobile machinery on construction sites, such as mobile cranes and bulldozers – an area which has not yet been addressed by regulation.
More likely is the introduction of low-carbon product standards for key industrial products. As part of the Industrial Decarbonisation Strategy (March 2021) aimed at de-carbonising industry, government is considering a voluntary standards regime for certain key intermediary products to enable manufacturers meeting those standards to receive low carbon certification. This is all subject to consultation with industry on how to tailor standards for particular products, and the need to define low carbon products. In developing the definition, embodied emissions of products would need to be considered taking into account the life-cycle of such products. It will be interesting to see the detail of this, and what products likely to be included, given that the construction sector is one of the biggest purchasers of industrial products. In developing any low carbon product standards, the strategy acknowledges that this will need to be done "without compromising the safety or suitability of materials used in construction and infrastructure". Elsewhere in the strategy, there is support for product innovation, developing alternative cements, alternative binders and cement formulations.
It's clear that the road to net zero will be a challenge and that all sectors have a role to play. In addition to reducing energy use to heat and cool buildings, we will see a renewed focus on resource efficiency and materials substitution in the construction industry. For those involved in the development of the built-environment, being carbon and resource efficient will increasingly be important on the road to 2050.
作者 Rebecca May