All-Electric Heavy Equipment
Can the Construction and Mining Industries Clean Up Their Acts?
If you happen to stroll past a large construction project, you may be struck by the noise, dust and fumes emanating from all kinds of tools and equipment. Not to mention the shouts of people trying to make themselves heard over the cacophony. It is unlikely that building sites will ever become places for quiet contemplation, but perhaps in the future the roar of combustion engines will be replaced by the hum of electric motors, and the diesel fumes will be no more than a bad memory.
Implausible? Ten years ago, most experts would have said that it was, at least in the foreseeable future. But since then, a combination of technological advances, shifting expectations and new regulations have led to unprecedented progress with electrification.
Electrifying most vehicles and machines involves the same basic process: you replace a diesel or petrol engine with an electric motor, which is powered by a cable, rail, batteries or fuel cells. That holds true for cars, trucks and trains, and it also applies to heavy construction equipment, such as bulldozers, cranes, excavators and wheel loaders.
Construction Site Equipment
Heavy equipment plays an essential role on almost all building sites, performing tasks such as excavation, pouring foundations and lifting heavy components into place. Traditionally, the machines that do this have been powered by diesel engines, but more recently there has been a move to diesel-electric powertrains. This avoids the need for a gearbox by converting the mechanical force generated by the diesel engine into electrical energy.
There are many benefits to this, including lower fuel consumption. By cutting exhaust emissions and noise pollution, it also improves the working environment for construction workers. As well as causing hearing damage, noise is a nuisance to nearby residents and businesses. The infinitely variable power output of diesel-electric transmission systems also improves performance, ensuring smooth acceleration and excellent torque.
Until the last few years, batteries were in most cases too expensive, heavy and bulky for them to be used to power heavy equipment. Electric forklift trucks were an exception to this rule, but they were mainly smaller models serving a niche market. With the price of batteries falling, and their energy density increasing, battery-electric heavy machinery is ready to move into the mainstream.
All-electric equipment takes the benefits of diesel-electric powertrains a step further, since it produces no exhaust emissions and is even quieter. Potentially, this could enable work in places and at times of day when it would otherwise be impossible. Complete electrification also comes with additional advantages: by eliminating the diesel engine, you remove the risk of oil spills and greatly reduce operation and maintenance (O&M) costs. Manufacturers who produce both electric and conventional heavy equipment claim that all-electric drive trains are more cost-effective in the long run.
Heavy construction equipment needing up to 100-150 kW of power is now widely available in all-electric models. This includes wheel loaders, excavators, cranes, concrete mixer trucks and even bulldozers. For the very largest machines, particularly if they are operated continuously, the batteries you would need to last you through the working day are still too big and heavy. For these machines, one option is to swap the batteries during the day. Where that is not possible, alternatives include hybrid engines, fuel cells and powering the machine via a cable – the latter is particularly viable for stationary equipment.
Mining equipment
The mining industry has a reputation for being polluting and destructive, and few people associate mines with green innovation. Nevertheless, the remote locations of many mines means they have been early adopters of solar powered microgrids. The main objective has been to limit the use of expensive diesel generators, but this aim has also coincided with new stricter standards and corporate environmental, social, and governance (ESG) goals.
Any move to all-electric mining equipment will similarly be driven primarily by cost, productivity and regulatory considerations. Chief amongst those are lower O&M costs, including longer service intervals. The simplicity and instant torque of an electric motor is also especially useful in the steep, rugged terrain at many mines, allowing vehicles to perform their tasks more quickly and safely. Finally, it is becoming increasingly important for companies to burnish their environmental credentials when seeking funding from financial institutions and markets.
The advantages of a better working environment – in terms of air quality, temperature, humidity, noise and vibration – are amplified in underground mines. The biggest benefit of this is to the health and comfort of the people who have to work there, but it also has a very important financial dimension. Ventilation is a huge cost centre, and using electric machinery can halve it. Electric machines create less heat than diesel ones, so cooling costs are significantly lower too.
The cost savings are even greater for new mines: if they are going to be all-electric, they can be designed with smaller ventilation and cooling systems than a traditional mine. Of course, using all-electric vehicles creates some new challenges and safety considerations, such as protecting batteries against fire risks, but the general consensus is that all-electric mines will be safer than their diesel counterparts.
Mines operate the world’s biggest trucks, and for the reasons discussed above, battery-electric drivetrains are not suitable for the very biggest. That doesn’t mean they can’t be electrified, it just requires slightly different technology: one 290-tonne dump truck is being developed to operate using fuel cells.
Specialist Heavy-Duty Vehicles
Normal heavy goods vehicles go beyond the scope of this post, but I will briefly touch on specialist heavy-duty vehicles. In the EU, cities have a legal duty to meet European air quality standards, and one of the ways they can achieve this is by electrifying their municipal fleets. Consequently, electric heavy-duty vehicles like refuse collection vehicles, snow ploughs and street sweepers are gaining ground. As they operate on fixed routes, it is relatively easy to design them with batteries that meet their needs.
Cleaner and quieter vehicles are popular with residents – particularly ones like these that often operate at night. Even in towns with no legal obligation to improve their air quality, promising to electrify municipal vehicles is therefore likely to be a vote-winner, provided that it can be done without raising taxes too much. That’s the catch: the upfront cost of electric models is still significantly higher than the diesel equivalents, so grants or loans to help with investment costs may be needed to really get this segment going.
Catalysing Change
A real momentum is building behind the shift to all-electric heavy equipment, driven by performance, total cost of ownership and regulations to reduce pollution. Epiroc, a Swedish manufacturer of mining equipment, reported that the second quarter of 2022 was its best ever for electrification.
Nevertheless, there is long way to go. As the ultimate client for very many construction projects, the public sector can act as a catalyst for change by specifying what kinds of equipment are allowed in its projects and supply chains, in the same way as with “green” concrete and steel. This is what is happening in Agder in Norway, which is aiming to become the world’s first fully electric region.
The world’s first all-electric mine is already operating, and others aim to follow in its footsteps. For new underground mines, all-electric operation may soon become the norm, whereas it will probably take a bit longer for that to happen with existing underground mines and surface mines. The average lifespan of most heavy equipment is just ten years, so once change takes hold, the transition could be quite rapid. Overall, there is plenty to be optimistic about, with both market forces and regulations pushing strongly in the same direction.