Two thousand percent: that’s the common margin of error when predicting the carbon footprint of infrastructure projects. The huge variance stems from a lack of standardisation in the way infrastructure carbon emissions are measured.
The carbon data problem is highlighted in a new report from the Net Zero Infrastructure Industry Coalition, ‘Is our carbon wallet empty?’, examining the embodied carbon of the UK’s £600bn construction pipeline to 2030. Mott MacDonald is a founding member of the coalition, working with clients and industry partners to take practical steps towards the UK’s goal of net-zero by 2050.
Every project built will result in construction-related and operational carbon emissions, all eating into the UK’s ‘carbon budget’ – the maximum net quantity of carbon we are legally permitted to emit in the next three decades. We wanted to establish the cumulative impact of all those planned infrastructure projects, yet with margins of error as high as 2000%, we are in real danger of underestimating our emissions trajectory and blowing the UK’s carbon budget. Our investigation revealed the scale of the carbon data problem:
Absent data
Quite simply, accurate data does not exist for the majority of projects in the infrastructure pipeline. We were able to gather accurate data for just 9% of projects, while another two thirds was estimated with the help of data drawn from sources such as Moata Carbon Portal, our own BIM-enabled carbon calculator, which has been used on numerous major projects.
Why the 91% gap? Data has either not been gathered, or nobody ‘owns’ data and will take responsibility for using it or sharing it, or the data is confidential. In some cases, data formatting makes it impossible to use – for example it can’t be converted from carbon per kilometre to carbon per pound spent. Altogether, ‘absent data’ makes it impossible to fully appraise the carbon emissions trajectory for UK infrastructure.
Lack of standardisation
Carbon data for different projects proved hard to compare because different scopes for assessment were used and methodologies weren’t transparent. For most of the projects we analysed, it was impossible to split data into material types. This obscured the contribution of each material type to overall emissions, and where reduction efforts should be directed. Based on construction industry averages over the last decade, we assumed that steel would account for approximately 40% of the pipeline’s capital carbon, while concrete/cement would account for 20%. More refined data would reveal how these proportions will change over the coming years.
Four steps to quality carbon data
The construction industry urgently needs to address these issues by creating a standardised, industry-wide approach to measuring and reporting carbon. Our report made four key recommendations:
1. Measure consistently
The industry must create and use a standard set of carbon emissions factors for all materials and products. These emissions factors must be universally accepted, and continuously reviewed and updated. The emissions factors should be integrated into design tools. Benchmarking sponsored by governments and investors should be used to identify best practice, inform decision making and drive down emissions.