With hybrid and electric cars becoming more commonplace, what does this mean for traditionally diesel-powered piling equipment and other construction machinery?
Electric or hybrid-powered cars once meant a slow and uninspiring drive but the arrival of Tesla and other premium brand sports cars into the arena has changed the market. Both the British and French governments are among those to announce an end to sale of petrol and diesel cars within 25 years and manufacturers like Volvo have said that it will only sell electric or hybrid cars from 2019.
It is clear that change is underway for road vehicles but construction equipment is largely powered by diesel engines and so far, no official announcements have been made concerning their use once these bans come into effect. Hybrid powered construction equipment was first developed over 10 years ago and it was also slow to be accepted and developments mainly focus on smaller machinery. Electric equipment such as excavators have long been used in mines and quarries but power cables add limitations.
It is hard to understand how the pace of change for road vehicles will be matched on site but Low Emission Zones (LEZs), such as the one for non-road machinery adopted in central London in September 2015, give an indication of changes that may become more widespread in the future.
Air pollution is a contributing factor for hundreds of thousands of premature deaths in Europe each year and diesel emissions have been classified as carcinogenic by the World Health Organisation. Therefore, reducing emissions from diesel engines is an important factor for improving health. In areas where air pollution levels are considered dangerously high, LEZs seek to improve the air quality and make it safer to breathe, by regulating the most polluting vehicles.
Under the London legislation, contractors must either replace or retrofit equipment that is more than 10 years old that was manufactured before the EU’s Stage III engine emissions regulations for off-highway equipment was adopted.
The legislation applies to equipment with power outputs of between 37kW and 560kW that is used on any construction site in the centre of London and sites building more than 10 homes or larger than 930m2 in Greater London. Some equipment will be exempt where pieces of equipment are not available at the emission standard stipulated or in the volumes required to meet demand in London.
According to the Mayor of London’s office, the legislation for construction machinery is expected to cut particulate and nitrogen oxide emissions by nearly 50% by 2020. Current estimates suggest that 12% of nitrogen oxide and 15% particulate pollution in London come from construction and demolition activity.
To avoid the expense – real or perceived – of having to pay fees to bring construction machines into restricted areas, construction equipment firms are increasingly being asked by customers to fit a diesel particulate filter (DPF) to machines, to reduce the diesel particulate matter (black soot) from the exhaust gas of a diesel engine.
“In recent years, there has been a definite upswing in requests for DPFs to be fitted to machines that are working in urban development and don’t have them as standard,” says Volvo Construction Equipment director of regional sales support (Europe) Kurt Deleu. “But it’s important to mention, this is not always a clear legal requirement [of working in the LEZ].
“DPFs are currently seen as an extra precaution in response to a perceived need to meet regulations in Low Emission Zones. But as regulations around LEZs continue to become stricter, it’s likely this trend will continue.”
While some contractors turn to equipment manufacturers for help, others have developed solutions in house. Keltbray’s environmental team has been working with Keltbray’s in house plant department to ensure the company machines meet LEZ requirements.
“We are committed to environmental improvements across our business, and although this is a tiered directive, we and a number of our clients are now working towards ensuring that our plant meet some of the stages ahead of the 2020 deadline to demonstrate good practice,” says Keltbray energy manager and environmental advisor Jenny Cottrell.
“We have retrofitted over 20 machines with custom made DPF units. Although this is a considerably bigger investment compared to using generic bolt-on units, we have found that the fixed design relative to kilowatt output is not suitable for our demanding demolition environment. Our investment in retrofit technology means that we get full life value from our fleet, while maintaining environmental and LEZ compliance with best available technology.”
Although electrically powered machines still need energy to be generated somewhere, they are seen as cleaner and the next step on from retro-fitting particulate filters to diesel engines.
Thames Tideway’s contractor Costain, Vinci Construction Grands Projets and Bachy Soletanche joint venture (CVB) is currently using an electrically powered Hydrofraise for the diaphragm wall work on the eastern part of the scheme. While the development and use of the machine at the site was driven by noise issues, it is clearly helping to minimise emissions from the site too.
However, use of the machine at the site was only possible because a suitable electricity supply was already being installed for the tunnel boring machine which will be launched from the site. For many piling and foundation projects, the programme of works is just not long enough to justify such an investment and the use of cables to power such equipment would add further limitations.
Volvo Construction Equipment unveiled a prototype for what is believed to be the world’s first fully electric compact excavator in London earlier this year. The EX2 is said to deliver zero emissions and offer 10 times great efficiency and 10 times less noise than a similarly sized excavator.
Volvo has said that the concept machine is purely a research project at this stage, but it plans to continue to develop technologies connected to electro-mobility so maybe one day an cable-free electric piling rig will become reality.
“Considering the seriousness of air pollution, and the moves governments are making to highlight it, this is an area we believe will continue to be high on the agenda and one we are committed to finding solutions for,” Deleu concludes.