News & Views

Our friends are electric – moving ground engineering to a greener future

According to the United Nations and the International Energy Agency, 39% of energy-related carbon dioxide emissions (CO2e) are produced by buildings and construction. This makes construction and the built environment an indirect driver of climate change, which has been responsible for geophysical disasters that claimed 1.3 million lives and $3 trillion of economic losses between 1998-2017. Taking urgent action to combat global warming and its impacts was therefore understandably one of the seventeen sustainability goals identified by the UN to achieve by 2030. Ensuring the availability of water, sustainable levels of consumption and reductions in waste are other key environmental objectives, which are within the footprint of the construction sector. Closer to home, the UK government has gone one step further, setting a net zero carbon target to reach by 2050.

As consumers, we are now acting on this, making decisions based more on environmental value factors than cost. Evidence can be found in many industries; take food for example – organic food sales have grown exponentially in the last decade, amounting to over a 200% rise in the ten years to 2018. The clothing industry is another good example, where eco-friendly consumers are prepared to pay more to purchase their garments from manufacturers who adopt organic materials, embrace circular sustainability models, as well as championing fair labour practices. One might argue that this is part of a clever sales pitch. For instance, ‘sustainable’ clothing brand Outer known very effectively use the iconic surfer and activist Kelly Slater in their campaigns. But why not? Marketing will be key in the economics of differentiating one product from another and supporting the, sometimes, higher relative cost of greener operations. Of course, food and fashion are no strangers to trends but the environmental movement with the support of millennials, epitomised by the redoubtable Greta Thunberg, will undoubtedly become increasingly important in the way we live our lives and the way we do business. After all, this generation are our future clients, our future legislators, even our future employees.

So, when will these personal purchasing choices translate into commercial decisions in the construction industry? Well to some extent it already is. Government departments procuring projects in excess of £10m use a balanced scorecard system. This emphasises environmental sustainability as a key strategic theme and deliverables such as climate change impact as critical success factors. Critics will point to the subjectivity of elements of the calculations, but it does at least provide a mechanism for more environmentally focused decision making. Many local authorities also now require BREEAM certification for non-domestic developments in their area as a condition of planning permission. This scheme has been around since 1990 and is a standard assessment method used to evaluate the building’s environmental performance in areas such as pollution, waste and ecological impact. Credits are added together to produce a project weighting, ranging from pass to outstanding. Similarly, CEEQUAL performs the role for civil engineering and public sector projects.

So how can we improve our practices, perform well in these assessments and progress towards net zero carbon? The design of structures themselves, and foundation solutions, provide opportunities to minimise carbon production. For instance, NHBC guidance on piled foundations shows that it has a favourable footprint when compared to deep trench foundations. Lean design methods avoid over-engineering, with increased load testing or, settlement reducing piles within a raft can often further reduce a projects material quantities and vehicle movements. There are also ways that the circular economy model can be effectively used in ground engineering. The Reuse of Foundations for Urban Sites (RuFuS) best practice handbook was produced by the BRE as long ago as 2006 to provide guidance on how old foundations can be effectively integrated into future site developments.

There are choices available in terms of the materials that we use which can provide a reduction in carbon. Our industry’s biggest contributor to CO2 is concrete. Traditionally, OPC or CEM1 cement has been used in mixes. But producing OPC is a very carbon-intensive process, using fossil fuels like coal to break down limestone in to OPC clinker and CO2. Now we have an increasing list of replacement options which either don’t produce greenhouse gases during manufacturing or are a by-product of other processes such as pulverised fuel ash (PFA) from energy generation. With the carbon calculator tools that we now have at our disposal; it is relatively straightforward to demonstrate the potential tonnes of CO2 that can be saved by adopting alternative cement types and recycled aggregates. Likewise, the carbon footprint of alternative foundation techniques can be quickly compared, along with the associated financial cost of such a decision. To facilitate our clients in making environmentally friendly decisions, the presentation of such information should be a mandatory requirement.

Our plant and vehicles are also becoming greener. The NRMM (Non-Road Mobile Machinery) emissions regulations, which are a Europe-wide regulation the UK has continued to adopt control engine types used in the city’s construction projects. This has already played a significant role in ensuring a reduction in Nitrogen Oxide and particulate matter which can cause health problems, especially in vulnerable group such as the young and elderly. This demonstrates the importance of strong legislation. Further consultation between government, manufacturers and contractors will be required as we seek to move towards zero carbon plant. The technology is developing, as witnessed by electric excavators from a variety of manufacturers and Liebherr’s LB16 50T fully electric piling rig. A bigger challenge perhaps is providing the infrastructure to support such equipment. It is of no use having electric powered machinery where the electric is produced by a large diesel fuelled generator. For urban sites, a pre-commencement condition should be having a suitable electric supply in place. Within my own business I’m looking at ways in which we can support the use of private electric vehicles and transition our fleet to fully electric over the next decade.

The FPS is seeking to address environmental sustainability issues by equipping the industry with the knowledge and skills needed to offer and utilise appropriate techniques. We are fortunate to have amongst our membership the talented and passionate pair, Luke Deamer and Martin Stanley. Luke, a Doctoral Practitioner with Keller, and the University of Surrey is investigating sustainability in the geotechnical sector. Martin Stanley of Bachy Soletanche, played a key role in the production of the EFFC (European Federation of Foundation Contractors) carbon calculator. Together they will be presenting the first webinar of our ‘sustainability series’. We have also identified the production of an industry ‘Route to Net Zero’ carbon discussion document by a working group as a key deliverable during the next two years.

For individuals that care about the natural world and may be considering joining the industry, there is a chance to help shape the development of the built environment in a positive way. As a geotechnical engineer, I can be involved in basement projects that minimise urban sprawl, brownfield site remediation schemes, as well as geothermal and wind energy projects. The possibilities are extensive and I’m proud to be an environmental activist working in construction.

Author – Steve Hadley, Chair, Federation of Piling Specialists