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The electrification of equipment in practice

On the way to emission-free construction

11 November 2022

Electrically powered construction machinery emits less nitrogen and CO2 and will be found on every construction site in the future. For example, in 2023 Heijmans is set to take eighteen electric machines into service, from crawler cranes and wheel loaders to rollers. These are expensive but necessary investments. And how do you make sure you have sufficient power at construction sites on time? Three Heijmans employees take you through the electrification of the company’s equipment fleet.

“Our ambition is to build completely emission-free after 2030,” says Math Dohmen, infra consulting director. “Heavy construction equipment, such as earthmoving and foundation machines, are big emitters on construction sites. That’s why we are investing heavily in the transition to the electrification of that equipment, replacing traditional combustion engines with one or more electric motors. The required power is generated using batteries. This ambition is part of our Energy Management Plan, our plan to reduce CO2 and other emissions and make our work more sustainable.”

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From left to right: Peter Schellekens, Twan Maas and Math Dohmen in the yard in Rosmalen. In the background are two battery containers, each with a capacity of 500 kWh.

“The electrification of construction equipment is the future. For everyone, not just Heijmans,” says Twan Maas, business manager at Heijmans Equipment Management. “Thanks to our investments and innovations, such as the electric wire crane, we are in the leading group. The supply and infrastructure for this equipment is constantly developing, both technically and in terms of standards and guidelines.”

“Lots of clients are asking for it,” adds senior buyer Peter Schellekens. “This is helping us realise our ambition. Because not every client is ready yet, we do have to be careful about operating losses. For instance, say you have an electric excavator running on a project. Then you’re not sure whether you’ll be able to use that in other projects. You can’t charge and store batteries everywhere. And if a machine is sitting idle, we’re not earning back our investment. But this should not be an obstacle to achieving our ambition.”

Saving

At Heijmans, the three colleagues are taking the lead in terms of making the equipment fleet more sustainable. Heijmans has now ordered eighteen new electric machines and five heavy machines are already in use. Approvingly, they see how the sustainability ambitions of other builders and clients are accelerating the transition to electric construction sites. Math: “The Clean Air Agreement signed by central government, water boards, provinces and a large number of municipalities is moving us forward on this front. They want this to permanently improve the air quality in the Netherlands. Together with the national government, the participating parties are looking to record a health gain of at least 50 percent in 2030 compared with 2016.”

Double investment

Twan sounds a note of caution: “We do have to be careful about raising expectations too high among our clients. You can present a hydrogen-powered asphalt spreading machine, but until it runs on green hydrogen, the energy supply is still not sustainable. That’s how you mislead clients. We always use green electricity to charge our electric machines.”

Peter thinks hydrogen is the solution for heavy machinery, but not in the short term. “This is only a sustainable source of energy if you use sustainably generated electricity to produce your hydrogen. In the future, we will use a combination of various energy sources, both battery-powered equipment and hydrogen-powered equipment.”

Availability

“Clients sometimes think we are taking electric equipment off the shelf,” adds Twan. “But we are not that far yet. We are limited by the capacity of conversion companies. In an ideal situation, we would be buying electrically powered machines directly from a manufacturer, because converting a machine is on average twice as expensive as a piece of equipment with a diesel engine.”

Peter says this is not due to unwillingness on the part of manufacturers. “Those companies want to become more sustainable just as much as we do, but they’re faced with the national emission standards of their various clients. In Africa and Asia, fuel quality is not as good as in Europe and countries there have different emission standards. This is why they still sell machines with traditional stage 3 internal combustion engines there. And they sell very few electric machines in those parts of the world, due to the lack of an adequate charging infrastructure. Manufacturers will only be in a position to become more sustainable more rapidly when they see more demand for electrically powered equipment.”

Charging and storage

Drivers can charge their electric cars almost anywhere in the Netherlands, but this is not the case for electric construction machinery. Twan: “Construction sites and our workshops are not yet equipped for electric equipment. It turned out, for instance, that you cannot store batteries from electric vibrating plates with regular vibrating plates, which run on fuel. So we need separate storage locations for batteries everywhere. This also applies to the large electric machines you want to park. And high-power charging is an extra safety risk. We need to come up with safety protocols and guidelines on this front.”

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Heijmans is now developing charging infrastructure that allows users to charge safely on building sites

Clogged power grid

“What’s more, you have to charge electric machines on a daily basis,” says Peter. “This is a major challenge, especially in infrastructure projects, where we are often building along a route rather than at a single location. The electricity grid can barely keep up with the transition and is getting more and more clogged. As a result, grid operators are now providing very few new connections. Sometimes you have to wait a year.”

Sea container

You can charge machines on construction sites in three ways: by driving to a power point, by changing batteries or by bringing power to the machine. Peter: “For our new electric wire crane, we have chosen option three. This 80-tonne machine is too big to drive to a charging point, so we bring a battery to them instead. This is a battery-filled shipping container, with a capacity of 500 kWh. We charge this through the normal grid. And you can use this battery pack to charge six passenger cars or a heavy construction machine in one go. Fully charging the wire crane takes about ten hours.”

“Despite the high costs and safety risks, Heijmans continues to invest in electrically powered machines and in the development of a charging infrastructure that will enable its people to charge safely on construction sites. Now the question arises as to whether we can continue to do the work at the same price,” Math concludes. “The price tag is even higher now. We think it would be good if (local) governments, together with builders, were to bear the additional costs and look at other financing options to keep the work affordable in the coming years. That is the only way we will achieve our ambition to build emissions free by 2030.”