Our Zero Carbon Construction Site Diary
Advanced Works onsite have come to a close. As we work with the customer on the next phase, we’re focussing on minor works with a limited onsite presence, but work behind the scenes continues as we consider some of the knotty issues relating to significantly reducing the carbon emissions from this scheme.
Understanding the financial costs associated with zero carbon construction is a critical element of being able to deliver it. On this scheme, one of our aims is to analyse and capture this in greater detail.
At the moment, and until this way of building becomes the norm, the upfront costs of lower carbon options are certainly higher, although in most cases, the costs are recouped over the longer term as lower carbon options can be more energy efficient for example, thus saving on energy costs. The aim of this project is to trial as many low carbon options as we can, without any additional cost to the customer. Once we’ve trialled them, we want to be able to replicate the best solutions across our other sites.
Our approach to delivering this at no additional cost has three key elements:
One of the common themes in this diary entry is the need for collaboration with innovators, the supply chain, academia and funders. It’s something Balfour Beatty prides itself on. Collaboration is key to a sustainable future and we are keen to hear from anyone who thinks they could collaborate with us on this project, or others, to deliver a more sustainable future.
Something that is likely to play a key role in making lower carbon options more cost-competitive, is the rising cost of the materials we traditionally use. For example, in April 2022, the rebate on red diesel ends meaning that the cost of powering our diesel plant will significantly increase. This price increase makes hydrogen fuel more cost competitive for our sites than ever before and we are actively planning our hydrogen route map.
Energy and fuel price increases, teamed with shortages in certain products (including Ground Granulated Blast-furnace Slag, bitumen, fuel, utilities, timber, plastic, steel and cement-based products) are also driving significant price increases for many traditional materials and are beginning to make lower carbon options comparatively more affordable, although this is something that is continually changing and evolving. If this is the case, it is likely to accelerate take-up and trialling of these lower carbon options which, in turn, should drive the cost of them down as they become more mainstream.
The work we are doing on this site will generate a large amount of topsoil which is of very high quality. As the name suggests, topsoil is the upper layer of soil, up to around 10 inches. It is usually nutrient-rich, fertile, and excellent for growing plants and vegetables. It takes around 100 years to make an inch of topsoil and as such it is a valuable and finite resource. The Royal Botanic Garden Edinburgh will reuse much of this displaced topsoil, benefiting other areas of the 70-acre Garden. However, there will be some surplus soil which cannot be reused within the Garden or accommodated in the design.
We always try to reuse topsoil on our sites. Where this isn’t possible, it would normally go offsite to be reused elsewhere. We typically look for other sites that need topsoil for their own developments or supply chain partners that can retain the soil and then sell on when others need it. Where this is not possible, our final option is to take the topsoil offsite for use as landfill cover, to restore landfill cells.
Trying to think creatively with the customer about how this could be used more sustainably in the local area, we offered the soil to local individuals and organisations and were delighted to be inundated with requests from the community, including schools, community groups and others. We have had requests for some 50 tonnes to be delivered around the local area for reuse, which we are in the process of distributing. We are able to do this as the Scottish Environment Protection Agency (SEPA) have agreed we can use the Greenfield soils protocol meaning we can work with the material as a clean material and not a waste. The reuse of waste at another location is heavily regulated, something which acts as one of the current barriers to circularity within the construction industry.
Having a construction workforce that is trained and ready to deliver net zero is essential to getting there. We need to invest now, because we know we will need them increasingly. This includes a whole range of skills such as low carbon construction, understanding the sourcing of materials and embodied carbon, digital skills, life cycle assessment/costing, carbon and water footprinting and designing in a way that takes into account both embodied and operational carbon and resilience to climate change. Given the urgency associated with climate change and decarbonisation, updating and refocusing people’s existing skills to ensure that they are fit for purpose is fast becoming a priority, as is creating a pipeline of people coming into the industry who have some of the new skills we’ll increasingly need.
We’re undertaking a Gap Analysis mapping the existing skillsets of our workforce against the skills we are increasingly seeing a need for. Work we’re doing in support of this includes:
One of the elements of this scheme in particular which relates to new green skills is the installation and operation of the ground source heat pumps for the district heating system.
The first phase of the scheme involves the creation of a new, efficient energy centre to replace existing facilities at the Nursery to the north of the main Garden. The new energy centre will introduce ground source heat pumps which, coupled with new low heat loss pipework, will result in a 17% reduction across the whole of the Royal Botanic Garden, Edinburgh.
Balfour Beatty has experience in delivering this type of technology, not least at the Caird Park Low Carbon District Energy Hub – a hybrid ground source heat pump, powered by a mix of renewables which supplies a district heating network to warm a large proportion of Dundee’s social housing, for which Balfour Beatty, Dundee City Council and ESB won the Carbon Reduction Award at the Scottish Green Energy Awards in 2019. However, the technology is still relatively new and involves a number of complex design considerations. There is therefore currently only a limited supply chain that is able to deliver these types of systems and to service them following installation. In practical terms, this means that we are working hard to source those who are already able to deliver this, and taking active steps to make sure our supply chain partners are ready and that we are able to capture and replicate this knowledge in our own workforce. We are also looking ahead to the handover stage to ensure a soft landing for the customer and that they have everything they need to operate and service the system in the future.
Key learning |
Our action |
On cost for zero carbon construction sites we are in a period of transition as we move away from red diesel. As the technology solutions become more readily available we will see a series of changes i.e. the move to battery powered tools. To ensure these transitions can be delivered at zero cost, we need to look at the whole cost not just the red diesel cost but its transportation / refuelling / containment etc. If we have a mains connection the charging infrastructure can be installed and the costs shared across the supply chain for charging. |
Learning shared with the Sustainability and Procurement teams and filtered back to the rest of the business.
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Topsoil is a precious resource and every effort should be made to reuse 100% of it. We have c.50 tonnes of soil allocated to local allotments and schools charitable initiatives as SEPA have agreed we can use the Greenfield soils protocol, meaning we can work with the material as a clean material and not a waste. We need to continue to collaborate with other UK regulators so that this valuable resource is classified as a material that can be reused and its inherent value is not lost by being classified as a waste. |
We are highlighting the approach we and SEPA have taken on this site to the UK Government and suggesting that they consider reclassification of topsoil. |
In order to secure sufficient people with the skillsets we need to undertake zero carbon construction, we need to work more closely with academia, CITB, the Supply Chain Sustainability School, Construction Scotland and others, to work out how we best future proof the future construction industry and help upskill the whole sector. |
Learning filtered back to the rest of the business, specifically Group HR. |
Where one part of the business and our supply chain partners work on an innovative, sustainable solution, we need to ensure that we are capturing and sharing the learnings and skills as widely as possible to ensure that we are able to deliver these solutions efficiently for all our customers and that handover to the customer is as seamless as possible. |
Learning filtered back to the rest of the business, specifically the Sustainability team. |
If you have observations or queries on the points outlined in this entry, please contact: Veena.Hudson@balfourbeatty.com.