How do we build in low carbon construction?
The level of activity within the construction sector is one sure-fire indicator of the health of the economy. The industry proceeds in waves; like buses, there is never a construction project when you expect one and then suddenly you get several in a row. In the South East alone we have had Heathrow terminal 5, the Olympic Park, Crossrail, Thameslink and Royal London Hospital. This is not to mention the resurgence in house-building that the Government is promising and the impact that the liberalisation of the planning system will have.
Setting aside the rights and wrongs of trying to build our way out of the recession, it is widely accepted that any new developments must be sustainable. Many, many years ago I remember doing some back-of-the-envelope calculations for Greenpeace to support a green building campaign which showed the necessity of low carbon construction. Bill Dunster, Bobby Gilbert and I refined these calculations for The ZEDbook.
Essentially, building replacement rates in the UK are so low that at least 80 per cent of the buildings around today will still be here in 2050. New developments therefore mainly add to the stock rather than replacing existing buildings. Running the numbers it becomes apparent very quickly that new projects must be both low carbon during construction as well as low carbon in operation if there is to be any chance of keeping to national climate change reduction targets.
Until the publication late last year of BS EN 15978 (Sustainability of construction works – Assessment of environmental performance of buildings – Calculation method) measurement of the embodied carbon in construction works had been largely ad hoc. Now the sector, well versed in applying and complying with standards, seems to be taking the matter of embodied carbon far more seriously and not just in the UK. Later this month, I am keynote speaker at an ASTM International workshop on the subject followed rapidly by an engagement to speak in November at the joint launch of a RICS advisory document and the GLA’s new guide to accounting and reporting embodied carbon emissions in construction (the latter of which I happen to have authored).
I mentioned in an earlier blog of some interesting industry research, covering 35 businesses, which I conducted during the development of the GLA guide that I would, at some point, be in a position to share. I can’t claim the sample is totally representative as responses were naturally biased towards those willing to respond to the survey. Therefore, consider these key findings as an optimistic overview of the sector’s engagement with embodied carbon.
How common are embodied carbon assessment of construction projects?
- Only three-quarters (77 per cent) of companies have undertaken carbon footprints of their projects
- Of these only around half have measured embodied carbon – the rest focusing on carbon in use
- From this is can be deduced that in less than one-third of projects is embodied carbon considered
- The good news is that, of those who haven’t performed an embodied carbon assessment, most are planning to do one
- The bad news is that, where studies were completed, only a minority were used to influence the design. Most served to merely report emissions.
What tools and methods is the industry using?
- Only one-quarter of those undertaking an embodied carbon assessment were using an established standard or guidance. Most were using an approach developed internally
- Almost all respondents said they would benefit from better accounting and reporting guidance
- Few used any third party tools to support the assessment. Most were using tools or spreadsheets developed in-house
- There was strong demand for a free, public emission factor dataset and benchmark data.