Electric pros and cons
27 March 2023
Balfour Beatty has shared the findings from a six-week trial in which electric plant was used by its team working at the Edinburgh Biomes project at the Royal Botanic Gardens in the Scottish capital.
And looking ahead, the infrastructure group says that changes could be needed in the ways contractors plan work sites in order to introduce alternative energy sources to diesel effectively.
As mentioned previously on the blog, the Biomes initiative includes improving the energy efficiency of the Garden’s iconic glasshouses (above) and constructing new facilities to reduce the organisation’s carbon footprint, while providing a bio-secure propagation environment.
The equipment used comprised a telehandler, a 2.5-tonne excavator, a 2-tonne dumper and 500mm compaction plate.
Writing on Balfour Beatty’s website, Jo Gilroy, Group Sustainability Director, said that a standard 110V site connection point was used for charging but that ideally a rapid charging connection, similar to those for cars, would be better on a larger site setup. This was because charging was slow, largely being done overnight.
On a larger site, a robust charging infrastructure would need to be in place, meaning that sites would essentially have to be redesigned to allow for effective – and low carbon – charging infrastructure.
“When setting up our sites, mains connections can sometimes be a barrier as there is insufficient capacity available within the local gird,” said Jo Gilroy. “This challenge will become more substantial as electric plant does develop and therefore net zero construction sites may need to look at on-site energy generation to allow charging of the plant. This would lead to a much larger temporary site set up, both in terms of land take, lead in times and materials.
“Furthermore, if all of the plant were plugged in at the same time, over lunchtime for example, there would be an electricity surge, so a charging schedule would need to be planned into the overall programme of works.”
As electric plant produces zero emissions, one main advantage is that is can operate in enclosed spaces or on smaller sites without additional ventilation and carbon monoxide monitoring.
Electric machines are also much quieter, which had pros and cons for the relating to the telehandler and the dumper. While they make a noise reversing, “they are so quiet during standard operations, our operating procedures and safety training would need updating to make sure we keep our workforce safe, or a noise would need to be added to ensure people know they are there – bearing in mind that people often hear before they look.”
Another plus was that operators found the machines very user-friendly and liked using them.
Looking further ahead Balfour Beatty is working with suppliers to explore the use of larger plant powered by combustion engines with hydrogen fuel and on hydrogen fuel cells to generate power.
The company is also exploring complementary technologies such as incorporating thin film solar panels on top of site cabins.
