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Five Stages to engineering a carbon-neutral future

Five Stages to engineering a carbon-neutral future

Author: Jyoti Sehdev, Engineer

Carbon footprint is a term defined as ‘the sum of all emissions of carbon dioxide (CO2) which are induced by an activity’. 

In 2018, Sky News claimed that the UK sandwich habit (and its associated carbon footprint) is as bad for the environment as eight million cars, with the worst offender being the ‘all-day breakfast’. Why? The carbon footprint of the activities which support the prepacked sandwiches we buy every day for lunch is huge, starting with rearing the animals to provide meat and dairy, growing the grains and vegetables for bread and salad, and transporting, refrigerating and packaging our favourite bites. To add to that, we then have the disposal of the food waste and litter generated by the sandwich industry. All of these activities release carbon into the atmosphere. 

From making a cup of tea, to typing up a document, to getting the tube home; almost every activity that we engage in has a carbon footprint and the engineering and construction industry is no different.

So, as engineers, what steps can we take to become carbon neutral?

  • Understand what makes up our carbon footprint: what are the sources of greenhouse gases across the whole lifecycle of the project?
  • Minimise that footprint where possible: can we switch to renewable sources of power? Can we capture carbon? Are we using sustainable processes? 
  • Offset the rest of the carbon you cannot remove from the process: what external projects can we invest in to offset our carbon footprint? For example, our projects often engage in tree planting, as a single tree can absorb CO2 at a rate of 21kg per year. At the HS2 Euston Enabling Works, the Costain Skanska JV is trialling a green wall on cabins, which will reduce the carbon footprint of the offices.

At Costain, we know that our engineers play a huge part in shaping UK infrastructure by not only in minimising the carbon footprint at each stage of a project’s life cycle, but also by advancing technologies and forward thinking, learning from the world around us to make our future carbon-neutral.

Here are the five stages of the project lifecycle that we influence to engineer a carbon-neutral future:

  1. Project conception
    First, we evaluate whether the project is necessary. Does the value the project generates outweigh the carbon footprint required to construct it?
  2. Design
    Our design engineers seek to minimise the volume of materials required through efficient design. Our designers also actively recommend materials with a low carbon footprint. Cement production generates 5% of the world’s carbon dioxide output. Alternative materials like timber have a much lower carbon footprint and can be designed in. At this stage, we will also advise on the potential of renewable energy sources to power the project. For example, on the London Bridge Station redevelopment project, Costain used geothermal piles to support and power part of the new rail station structure.
  3. Complex delivery
    On site, we actively choose complex delivery methods which have a low carbon footprint, such as using recycled aggregates and Forest Stewardship Council (FSC) timber, instead of using virgin stone and unsustainable materials. We constantly update our supply chain to include local suppliers, reducing transport distances, and look to minimise water consumption, for example by using mist guns instead of hoses for damping down dust on site.
    Various hybrid and electric excavators and dumpers have been trialled on HS2 Euston Enabling Works project in association with Lynch. Once run off the grid, we can power these by renewable energy.
  4. Maintenance
    Our engineers design out maintenance requirements prior to complex delivery by choosing materials and forms which require little maintenance. Costain is leading in this area with its research on self-healing concrete.
    Maintenance design is also an opportunity to maximise the use of multidimensional BIM to predict the maintenance needs of every asset on a project. By creating a digital model of what has been constructed, then tagging each asset with a maintenance regime, we can encourage proactive maintenance to get the full lifespan out of an asset, rather than responding reactively following a failure which could potentially damage other assets in the vicinity.
  5. Demolition
    Finally, our engineers will also design for the demolition/end of life of a structure to contribute to a circular economy. For example, structures can be designed to be easily demolished such that the different materials can be easily segregated to allow for reuse or recycling. Our clients help focus the mind on this by setting sustainability targets, such as on HS2 where 95% of waste must be diverted from landfill.


The International Panel of Climate Change issued a report in 2018 which states we must curb the rise in temperature of the globe and stay within 1.5°C above pre-industrial levels, or else face a dramatic difference in our global environment. This poses a huge challenge which must be tackled on an international scale. Reducing our carbon footprint, both within Costain and on the projects we design and deliver, is one way we are contributing to this effort. Get in touch using the details below to see how Costain can help you reduce your carbon footprint and learn more about our Carbon Infrastructure Transformation Tool here.

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