3 March 2022 | Net Zero | Our Work

Carbon calculator chaos 

David Ogden, Operations Director at Colas Ltd, highlights the range of carbon calculators available to help the sector decarbonise and things to consider when choosing one. 


With our focus quite rightly on decarbonisation in the highways industry, there is no doubt that we are all looking for tools that can help us in our decision making.

Understanding where the carbon exists in highways maintenance and new schemes is crucial in being able to identify where we can reduce or eliminate it as we strive towards net zero.

It is probably worth going back to basics for a moment. We know that ‘carbon’ is bad, but why is there so much hype when it comes to climate change with regards to carbon?

Carbon is part of several greenhouse gases (GHG) which cause the greenhouse effect. Too much of these GHG being released into the atmosphere has caused the planet to heat up too much and led to the current climate crisis.

In order to reduce this from happening further it’s important that we understand how our activities impact the environment. We do that by monitoring our carbon footprint, which is measured in ‘tco2e’, – tonnes of carbon dioxide equivalent. This means that it takes into account all of the greenhouse gases including:

  • Carbon Dioxide
  • HFCs – Hydrofluorocarbons
  • Methane
  • NF3 – Nitrogen Trifluoride
  • Nitrous Oxide
  • PFCs – Perfluorocarbons
  • Sulphur Hexafluoride

With the carbon footprint including such a wide variety of activity areas, it has been split into three main scopes to make it easier to understand and deal with. These are the ‘scopes’ that are frequently referred to when identifying the carbon we are calculating:

Scope 1, Direct Emissions – from company-owned and controlled resources. In other words, emissions released to the atmosphere as a direct result of a set of activities, at a company level.

Scope 2, Indirect Emissions – are indirect emissions from the generation of purchased energy, from a utility provider.

Scope 3, Indirect Sources – covers all other indirect sources and splits into two further areas, 3A and 3B, or in other words Upstream and Downstream. Scope 3 can be incredibly broad and ultimately difficult to measure, but essentially equates to approximately 70% of the full carbon footprint.

These emissions are those that an organisation cannot control and can include a long list that is difficult to track and account for and even harder to reduce.

So, we come onto carbon calculators which clearly have the potential to support effective decision making by providing the information needed to understand these scope 3 emissions and reduce carbon footprint. We estimate there could be more than 30 carbon calculators currently in use in the highways sector. Could this lead to a potentially chaotic approach to carbon calculation? It’s important that the calculation piece is standard and correct for the calculators, but it is also important to consider the same approach with the figures that go into the calculator for each element. For example, if you assume a standard CO2 value for diesel, this may actually depend on whether you have a modern fleet or an old fleet and the same could be said for different elements of the supply chain e.g. bitumen where different production processes may have been used resulting in a different CO2 value.

To avoid this potential chaos, it is important that at this stage of decarbonisation in the highways sector, we truly embrace a collaborative approach. Working across local and strategic networks, finding a way to develop a common foundation of how and what we ‘calculate’ so that we are all looking at the same picture. This will allow us to work together to innovate and accelerate towards net zero.

And let’s be honest, accelerating our efforts is crucial in achieving our shared goal of decarbonisation. If we can create a common foundation with a standard agreed calculator this should speed up our understanding and, therefore, adoption of new lower carbon solutions. It is important to recognise that it is not just that we reach zero carbon by the date set by your organisation, the speed that we do it is vital. For every tonne of CO2 we save today, we save this forever. We are all looking at targets and trajectories but there is an urgent need to start saving CO2 now.

At Colas we have seen this collaborative approach be highly successful in Europe where Colas was part of a project with a number of suppliers and bodies who developed a complimentary international industry-derived comparison tool. SEVE enables the comparison of different solutions across the whole value chain, demonstrating the CO2 values throughout in order to explore scenarios which can support progress to net zero. Now commonly used in a number of European countries, this collaboration proved beneficial for both contractors and clients who now a have a consistent and reliable tool to support decarbonisation decision making.

We believe that there is strong appetite here in the UK for a more collaborative approach to carbon calculation and foresee progress this year. In the meantime, if you are using one, or looking to use one soon, be sure that you are clear about both the calculation and the figures being input into the calculator.

Colas and Breedon are acting as primary partners for a series of exclusive webinars entitled ‘Practical steps on the journey to net zero’ which are being delivered by the Local Council Roads Innovation Group (LCRIG).

The launch event takes place on 22nd March at 11am.

You can find out more information about the event and register here.