With the United Nations Climate Conference (COP26) approaching in November 2021 and pressure building to meet the U.K. government’s net zero targets, engineers know we need to make sustainability a key feature of businesses, projects and supply chains. Addressing greenhouse gas emissions is naturally integral to this.

Many have heard of scope 1, 2 and 3 emissions, but not everyone fully understands “scope 4” emissions. This unofficial term is used to describe the avoided emissions as the result of good design of the products and services a company produces, rather than its own operational emissions.

Integrated project delivery firms can generate significant positive environmental impacts by embedding sustainable choices into their entire end-to-end process, from engineering design to procurement to construction.

But where to begin to make this a reality? Here are five key questions substation engineers need to be asking to kick-start our project sustainability strategies.

1. Can I reduce the amount of material in the design?

As a rule of thumb, reducing the amount of construction material used in the design process reduces the project’s carbon footprint. This can also enhance the efficiency of the building process. Engineers should always consider alternative construction methods to design out material. Using helical piles rather than concrete foundations, for example, significantly reduces the amount of concrete required.

Components can also be designed out to reduce the embodied carbon. Designing a single-step process that takes voltage from a very high to a very low level, rather than a more common two-step process, requires less equipment and enhances value. For example, in Birmingham many substations jump straight from 132-kV to 11-kV without an intermediate 33-kV step.

Spare space on project sites can be used to develop custom solutions to sustainability problems. When designing a new substation for the HS2 enabling works, Burns & McDonnell included an on-site rainwater harvesting system, eliminating the need for a water supply line to the remote location near Long Itchington. Saving resources in this way can make a project both more sustainable and more cost-efficient.

2. Could I choose a more sustainable material?

Engineers should make it a priority to understand how to utilise materials with lower environmental impacts, or that contain recycled content, within the applicable design standards. Concrete, for example, is a material with a relatively high emissions impact, but there are plenty of low-carbon options available using non-cementitious alternatives. Recycled steel can be an effective option and is becoming more popular.

In addition, engineers should be prepared to challenge clients to think about the impact of the materials they accept. This can be achieved successfully through strong partnerships underpinned by consistent and honest engagement. Sustainability is a high priority for many clients, who will welcome challenges of this kind.

Don't know whether materials have a high or low impact? Check out this database of embodied carbon footprints.

3. Can I reduce emissions from transport?

People have improved at working remotely during the past year, and consequently have reduced emissions generated by transport. As the work situation evolves, we must continue to adapt to sustain and enhance the benefits of this trend for our projects.  

Travel to job sites can be reduced effectively through technology such as digital site scans, which can result in fewer site visits overall, as well as fewer required personnel on any given visit.

Procuring materials and services through local suppliers can additionally minimise transport distances. Clients are increasingly expecting this of their suppliers. Not only is this type of mindset good for sustainability, but it’s also good for the local economy and community relationships.

4. Can I make better use of the spaces in and around the project site?

Reducing the spatial footprint of the substation can enable environmental gain by making extra space available for biodiversity and natural capital schemes. The space surrounding substation sites can be repurposed as biodiverse habitats that help reduce the net emissions of the site and repopulate local wildlife. Creating habitats such as bat boxes, natural animal shelters and bee embankments surrounding the substation can be done quite simply. Doing so provides opportunities to work with local conservation groups for a consistent local approach.

Appropriate landscaping can enhance the overall habitat for wildlife and value for local communities. Remember, however, to choose flora and fauna that are consistent with the area.

5. Can I make a design choice that would reduce the amount of waste at end of life?

Engineers should be asking how and where they could employ circular economy principles to reduce the consumption of finite resources. Think “cradle to cradle” rather than “cradle to grave.” This means choosing components that can be reused or refurbished in collaboration with the manufacturers. Making designs modular can also produce value and efficiency; if a faulty component is found, only that one module would need to be replaced.

There are a number of innovative levers we as engineers can pull to increase the sustainability of our projects and supply chains. Apart from keeping our own houses in order when it comes to environmental, social and governance (ESG) factors, clients generally expect high environmental standards on their projects and are rightly asking us to deploy sustainable principles across the board. Embedding sustainability into our work is therefore crucial to the success of our businesses, our sector and our economy. It’s also the right thing to do, and our industry has to play a central part in meeting net zero emissions targets. Infrastructure is not just a collection of physical assets set across the landscape. It is an ever-changing legacy that continues to evolve with us, and it must be treated as such.


As the U.K. retires fossil fuel plants and increases its reliance on renewables, utilities must implement strategies to bridge the transition. Foresight and flexibility are keys on this path to decarbonisation.

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