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“All-electric plant isn’t yet a realistic option for our bigger sites, or for heavy plant,” Balfour Beatty group sustainability director Jo Gilroy says. “Just as the range on electric cars isn’t there yet, so the length of time plant can operate flat-out is an issue for the construction sector.”
She continues: “It’s very difficult to make electrification work for big pieces, especially without a mains grid connection – and we need to ensure that there is capacity in the network. The range when they are not plugged in is limited. These larger pieces of electric equipment can also be twice the price of standard plant, and customers are often not prepared to pay the increased hire charges for them. Our view is that, for heavy plant, the priority for the industry has to be to accelerate the energy transition to hydrogen rather than relying on electric to provide the solution.”
By speaking out on the short-comings of battery-power, Jo Gilroy is once again going against the group-think that so often appears to prevail. It was she who last year called out the hype surrounding HVO – hydro-treated vegetable – as a low-carbon diesel-replacement fuel. HVO, she said, ultimately risked causing deforestation and the draining of peatland and marshland in countries such as Malaysia and Indonesia, and said Balfour Beattty would therefore not be using it. [See our previous report, Bursting the HVO bubble].
Now she is seeking to shatter the hype that surrounds battery power.
Balfour Beatty ran a six-week trial at the Royal Botanic Gardens in Edinburgh, simultaneously running a telehandler, a mini excavator, a two-tonne dumper and a compaction plate. The kit can be twice the price of conventional diesel-powered options yet failed to perform as well, despite all the bold claims of equipment manufacturers.
While the dumper worked well, giving a full eight-hour working day, and the wacker plate was good, the telehandler and excavator could manage only four hours when working at capacity.
“If the machines aren’t able to work to the same capacity as diesel plant, it impacts on programme and on cost, which makes them less viable at scale for larger sites,” Jo Gilroy says.
Battery-power remains a good clean alternative for smaller plant, she says, such as drills, breakers and wacker plates, which need less maintenance and can come with interchangeable batteries. But for mobile plant Balfour Beatty is swinging behind hydrogen.
“We are leading on work to make combustion engines work with hydrogen fuel through our partnership with JCB and Sunbelt Rentals, which we hope will be ready within the next 18 months for plant such as telehandlers, traditional digger sizes – big, but not massive kit. We are also working with GeoPura and Siemens Energy on hydrogen fuel cells to generate power without an electrical connection. The potential of this work is huge. Replacing the diesel generators that power our site mobilisations and compounds with hydrogen would see a significant reduction to our carbon footprint, given that 46% of our sites sampled use diesel generators to power temporary accommodation units on site. This is industry-leading, but very expensive work – which makes business cases less viable. Our intention therefore is to work towards setting a cost per tonne of carbon, so we aren’t only looking at headline costs and value, but are being responsible by valuing the costs in terms of carbon savings as well.”
However, it is not a simple journey.
“Critically, there is not yet enough green hydrogen being produced,” she notes, “and there remain challenges in terms of the infrastructure for transporting hydrogen around the country. This means that it will be 2025 at the earliest before these become fully viable solutions at any scale.”
Jo Gilroy’s full report on the Edinburgh trials is available on Balfour Beatty’s website.
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