Our construction activities contribute to global carbon emissions. Traffic, power generators and site lighting all play a part increasing our overall emissions.
This year we combined forces with our construction partners Galliford Costain Atkins (GCA) and Kier Murphy Interserve (KMI) to investigate the impact of these activities using the Environment Agency’s Carbon Calculator tool. The tool requires information such as the amount of diesel usage by generators and plant machinery, the number and size of portable offices on site and vehicle movements due to deliveries, waste removal and employee travel. Standard conversion factors are then used to calculate an overall carbon footprint from all these sources.
The projects analysed were chosen to reflect the variations encountered on different projects to see whether these affected the carbon levels involved in construction. 15 different projects were analysed of different sizes and durations, in various geographical locations, some at water and some at sewage treatment works. In addition, details of the project value, the number of hours worked and the geographical footprint of the project site were all recorded. This was to determine whether there was a relationship between any of these factors and the carbon footprint of the works.
We discovered that there appeared to be a strong relationship between the financial cost of the civil engineering works on a project and the carbon of construction. The graph below illustrates this.
We were also able to see that certain construction activities were much more carbon intensive than others. The graph below shows a selection of the projects’ carbon emissions broken down by source.
Plant emissions due to diesel usage were often the biggest contributor together with employee travel. This was almost always the case, regardless of the variations in the type of works.
Further investigation showed that the carbon footprint of construction activity actually forms only a very small percentage of the overall carbon footprint of our projects. This is in comparison to the carbon embodied in the building materials used and the energy required to operate it over its lifetime.
Every small difference we can make matters. Now that we have this understanding, we’ll be able to predict and itemise the typical carbon footprint of a project and find ways to reduce it during planning. We also have the last piece of the puzzle in knowing the overall carbon footprint of our capital investment projects.
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