Hertfordshire County Council has completed all-electric highways works, with both plant vehicles and worker facilities powered without diesel or petrol.
Thought to be the first local authority in southern England to trial such works, the footpath reconstruction sites in Letchworth and Stevenage used electric and zero-emission equipment to carry out resurfacing and repairs.
In collaboration with infrastructure partner Ringway, the works involved the following all-electric equipment on site:
- Eco Smart Zero Emissions Welfare static unit (towable). With a gas back up.
- 7.2tn Electric Vehicle
- Small Electric Van
- Electric Mini Excavator
- Electric Compactor Plate
- Electric Disc Cutter
- Electric Breaker
- Electric Hedge Cutter
- Electric Backpack Blower
The larger plant type requires 'plugging in' from designated charge points/convertors or converted into 240v, straight into a plug socket overnight.
The council and Ringway have been working together to develop proposals to upgrade the infrastructure in the depots to support the increased use of electric vehicles and plant. Hertfordshire pointed out that further significant investment in the depots was required.
Batteries and plant are charged in one of the highway depots and the 'current electricity supply in our depots is from a sustainable source,' a spokesperson said.
The trial helped establish the cost and practicality of using electric equipment in comparison with traditional fuels as part of Hertfordshire's overall commitment to be net zero in its operations by 2030 and a net zero county by 2050.
A spokesperson highlighted that the equipment was hired for these trials, and as with any new technology, the initial costs are quite high - the excavator is currently one of only five in the country they said. The council did not give Highways a cost breakdown but said 'as the equipment develops and its use increased, we would anticipate that the costs will reduce'.
During the trial, the welfare unit was used for several full days. These units are self-charging using solar panelled roof/hydrogen cells. The digger did four hours of work each day, which matches up with 'the norm even with our current diesel/petrol models' a spokesperson said. This digger shift used approximately half a charge each day so generally every couple of days it would need to go back to the depot to re-charge overnight.
As long as the switch is off, the battery retains the charge, so the digger can be left on site for use the next day. All the other equipment, including the breaker and disc cutter, take interchangeable batteries which are stored on site and charged back at the depot.
A spokesperson for the county council told Highways: 'These were planned footway reconstruction works within residential areas. There were two different jobs over a course of two weeks, both teams have around five people ranging from skilled operatives to plant operators over an eight-hour shift.
'The two gangs typically work on our larger planned works so would remain on site for long periods that vary dependant on the job at hand. These two particular jobs consisted of 519.4 square metres of take-up and relay of footway tarmac, and the other was 180m2 of the same respectively.
'Our intention for these works; with the size and time scales was to ensure that we collected as much data as possible to check the viability/ability of the equipment, the impact on the environment, risk factors and the benefits, to name but a few.'
Cllr Phil Bibby (pictured above), Hertfordshire CC’s executive member for highways and transport, said: ’I’m delighted that Hertfordshire is the first such trial of an all-electric work site in southern England. The initial signs are very encouraging, and we look forward to working with Ringway to create even more electric sites in the future.’
Data from the trial is now being 'thoroughly reviewed before wholesale changes are made' – this includes factors such as the reduction in emissions, productivity, battery life and any health and safety issues.
There are some activities in Herts that have already made the transition to electric operations. For example, all the strimmers and blowers are fully electric and there are five electric vans on the contract.
A spokesperson said: ‘Over the next three years we will be retendering our main highway contracts and sustainability will be a key objective under the new arrangements and we will be setting ambitious targets in support of the Sustainable Hertfordshire Strategy.'
The work teams themselves gave 'good all-round feedback' from the trials.
Operatives said the larger plant was able to deliver the same amount of work without any issues, with the ability to do everything they needed it to. The smaller equipment needs some improvements apparently, either they were too small or did not have the power to do everything.
The asphalt materials that Hertfordshire currently uses are conventional as these are specified in the contract.
The council noted that lower emission warm mix materials were available and 'are being considered by the highway teams as part of our drive to become a more sustainable service'.
