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.
Hi Craig,
Have you heard of eTool?
It’s a free, online LCA software that measures embodied and operational carbon of the built environment. Either as designed or as built so can be used on new buildings to lower impacts during design and construction or for retrofitting established buildings with the right low carbon options in terms of materials, renewable energy systems and thermal performance.
It is an Australian based tool, but uses the Bath University database and is currently adding UK and USA location data into it for transportation impacts. It covers carbon, energy, life cycle costing, Greenhouse Gas emissions and has the capabilities to add water, toxicity and land clearing.
Can be used for residential, commercial, development and infrastructure projects. Worth a look – http://etool.net.au/
- Siobhan
Siobhan,
Thanks for the heads up. Have just had a play with the etool which appears to use, not just Bath data, but also Australian specific input-output data. That is, it converts Australian Dollars directly into carbon using a mapping process known as input-output analysis.
I like many of the features of the etool, especially the shared library, which allows components to be re-used. I cant see myself using it for UK/US projects just yet. I use Footprinter (www.footprinter.com) configured for construction. It is pre-loaded with Bath ICE and other factors sets. The features I find most useful are the ability to upload cost plans to rapidly ‘describe’ the development (using NRM classification system) and the ability to share my results with other members of the design team and give them access to the underlying data for them to view and/or edit. This is particularly useful when working internationally as I often get local partners to manage the emission factor set I am using.
Cheers
Craig
Hi Craig,
eTool LCA doesn’t rely on “input-output” data at all. It’s actually all process data. For the moment we’ve switched all users to the Australian dataset but imminently we should be re-introducing the Bath data set and other regional data sets to be selected on a project by project basis.
We’re a little wary of straight input output data as it uses a lot of regression to allocate the environmental impacts based on financial transactions. It’s notoriously inaccurate for determining the actual sources of environmental burdens. It can be really useful for expanding the system boundaries of assessments. It works reasonably well for energy, a little less accurately for CO2 and less and less accurately for more obscure environmental impacts (water, toxicity, land use etc). We have opted at this stage to concentrate on process LCA databases for eTool LCA because they’re more rigorous of their accounting of impacts applicable to the construction products and processes.
A close look at eTool LCA reveals that it definitely doesn’t rely on mapping $ user inputs to carbon intensities. The users have to enter material quantities, and this is what yields the carbon figures and cost data (carbon and cost coefficients are not related and come from separate sources). We have included the costs in eTool LCA so you can get fast Life Cycle Cost outputs while at the same time understanding environmental impacts. The cost data is not a requirement for the environmental data.
Being web based, projects can be shared and accessed globally which as you say is really helpful for working within an international team. Also being free to access means you can get in and see how it could work for you or your organisation.
Cheer,
Rich