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Is battery-power the answer to the quest for zero-emission construction plant?

13 Dec 19 Phil Bishop unwraps some of the latest battery-powered offerings and looks at some emerging low-carbon power options.

It is now UK government policy that all new cars and vans will be effectively zero-emission by 2040. Obituaries of the internal combustion engine can now be prepared. We are witnessing the dawn of a new age of battery-power.

And where on-highway vehicles lead, off-highway construction machinery is sure to follow.

Battery-powered equipment on construction sites is not itself a new development: mobile elevating work platforms (MEWPs), for example, are already routinely battery-powered for use indoors.

To date, however, harder-working machines like excavators have almost exclusively been diesel-powered...almost. Hybrid machines exist, and there are excavators that can plug into the mains, with the hazard of a trailing cable. 

The battery-powered Wacker Neuson E217e
The battery-powered Wacker Neuson E217e

But in the next couple of years we will start to see more and more battery-powered excavators, taking advantage of rapid improvements in lithium-ion battery technology. Diesel retains many inherent advantages over battery-power, but the world is changing. 

Advances in diesel engine technology have made the latest machines close to emissions-free, but for many this is still not good enough. And they are also noisy.

Diesel engines compliant with EU Stage V emissions standards may meet even the most rigorous regulatory requirements, such as the London Ultra Low Emissions Zone, but tier one contractors are increasingly looking to gain competitive advantage by demonstrating their sustainability credentials. Replacing diesel with electric, rightly or wrongly, is seen as a way to achieve this. 

At recent major trade shows manufacturers have put their latest developments in battery-electric construction machinery at the forefront of their displays. In each case, it is claimed the battery-powered machine is no less powerful or productive than the traditional diesel model on which it is based, although commercial developments to date have generally been restricted to compact sizes. 

We have seen Takeuchi’s e240 prototype, for example, and Wacker Neuson’s EZ17e and EZ26e. Wacker Neuson already has battery-powered construction equipment in its product range, including rammers, wheeled loaders, a vibratory plate and a tracked loader – but these are its first battery diggers.

Hyundai's 3.5 tonne prototype is powered by Cummins' BM4.4E battery modules
Hyundai's 3.5 tonne prototype is powered by Cummins' BM4.4E battery modules
Hyundai Construction Equipment (HCE) and engine producer Cummins have collaborated to produce an electric-powered mini excavator prototype – a 3.5-tonne excavator which is powered by Cummins’ BM4.4E flexible battery modules (4.4 kWh each). 

Hyundai’s commitment is clear. Chief technical officer DS Kim says: “As electric vehicles continue to expand their share in the automotive market, we are simultaneously seeing the electrification of commercial power systems being pursued by many as both an environmentally friendly and economically sustainable solution for construction equipment. HCE anticipates mini excavators, which operate in urban workplaces close to residential areas, will be a prime candidate to electrify to meet zero-emission and low noise requirements in the near future.”

Smaller manufacturers are also getting into the game: Eurocomach, part of the Italian Sampierana group, showed an all-electric ES12X (1.2-tonne) mini excavator in concept form at Intermat 2018 in France.

At the Bauma fair in Germany in April this year, battery-power was a core theme. Caterpillar showed a concept Cat 906 compact wheeled loader powered by a 41kW lithium-ion battery that takes three hours to charge. Cat says that on a fully-charged battery, the concept machine can operate in a medium-duty application, such as mixed truck loading or material handling, for up to 4.5 hours or up to 6.5 hours with a one-hour top-up charge during the lunch break.

Komatsu unveiled a pre-launch electric mini excavator based on its expertise of hybrid construction equipment and electric forklift trucks. When fully charged, the battery offers up to six hours of operation depending on operating conditions, Komatsu says. Again, a quick charge during the lunch break can extend working hours. 

Since Bauma, Bobcat and JCB have taken things beyond prototype and gone into serial production, with Volvo close behind and set to follow suit next year. 

At 1:08pm on 11th July 2019 the first Bobcat E10e one-tonne electric micro-excavator came off the production line at the factory in Dobris in the Czech Republic. 

The zero-tailswing E10e, just 710mm wide, is built on the same platform and produced on the same production line as the diesel-powered E08 and E10z mini excavators. The E10e has a lithium-ion battery pack that runs for up to four hours on one charge. By using an optional external 400V supercharger, it can be recharged to 80% of its capacity in less than two hours. In this way it can be made to serve a full working day with normal work breaks. The battery can also be fully recharged overnight by using the on-board charger from a standard 230V grid.

The Netherlands, Sweden, Germany, Austria and Norway have been selected for first shipments. How soon we see it in the UK, if at all, depends on perceived market demand.

Just six weeks after Bobcat’s debut, JCB announced that not only had it gone into full production but had already delivered to dealers more than 50 units of its battery-powered 19C-1E excavator, first unveiled last year.

Orders for the 1.9-tonner are said to be ‘rolling in’ from customers from across Europe and North America and an early high-profile appearance of the new digger was made on an HS2 site in London 

Three or four lithium-ion battery packs provide a 15-20kWh storage capacity. There is an on-board charger with 110V input for 12-hour recharging capability (or the option for 230V charging when required, with eight-hour recharging time) and a fast-charge option allowing a full charge in less than two hours.

There is also a battery management system to help ensure full-shift availability. This kind of technology is crucial since you don’t want to run out of juice when you are out of reach of your power source. A diesel-powered machine that runs out of fuel just requires someone to get a jerry can; a battery-powered machine that runs flat is effectively broken down until it is recharged. And if the cable doesn’t reach the power source, that means it needs another machine to pick it up and carry it to sanctuary.

Assuming no such cock-ups, JCB cites research showing that charging costs over the first five years of ownership will be 50% cheaper than using traditional red diesel and servicing costs are expected to be ‘up to 70%’ lower than on similar-sized diesel models.

Volvo Construction Equipment may have been slower to go into full production, but it appears to have the deepest commitment to electric. From mid-2020, Volvo CE will begin to launch its range of electric compact excavators (EC15 to EC27) and wheeled loaders (L20 to L28), stopping new diesel engine-based development of these models.

JCB’s attitude, by contrast, is that battery and diesel both remain very much part of the product mix so long as customers demand them. It has no plans to phase out diesel engines, even on smaller machines, and says battery technology is not yet ready for bigger ones.

JCB 19C-1E is now on the market
JCB 19C-1E is now on the market
 

JCB’s head of innovation and growth, Tim Burnhope, says: “We have launched our first electric excavator and the response has been fantastic with sales all over the world in the first few weeks of full production. 

“Electric technology is currently only suitable for small machines rather than the large excavators used on major housing and infrastructure projects. However, it continues to develop and will have further uses, particularly in compact and mid-range equipment. 

“Beyond that, clean diesel will continue to play a major part in the powering of JCB equipment. JCB is a leader in innovative clean diesel technology for construction machines used on housing and infrastructure projects. 

“Future powertrain offerings will include electric battery/motor systems for small machines and combustion engines for larger machines. The combustion engines will emit practically zero NOx and particulate emissions and run on carbon neutral fuels. Fuel cells might be a good solution for some applications when the technology and fuel distribution has matured. The future will have a variety of powertrain solutions matched to applications and usage,” concludes Burnhope.

Volvo's 2.5 tonne ECR25 is fitted with 48V lithium-ion batteries
Volvo's 2.5 tonne ECR25 is fitted with 48V lithium-ion batteries

Volvo’s 2.5-tonne ECR25 is fitted with 48V lithium-ion batteries and a single electric motor. The batteries store enough energy to power the ECR25 for eight hours in its most common applications, such as utility work, Volvo says. The L25 has lithium-ion batteries which allow for eight hours of operation in regular applications. The L25 also has separate motors for the drivetrain and the hydraulics. Decoupling the subsystems has led to higher efficiency in both the systems and the entire machine, Volvo says.

Both the ECR25 and L25 have on-board chargers for overnight charging via a regular household socket. A fast charging option, requiring more powerful grid access, will also be available.

Volvo’s battery-powered ECR25 mini excavator made its UK debut in May, building one of the gardens at the Chelsea Flower Show. On a landscaping project like this, the lack of polluting spew reduces the risk of damage to the precious trees and herbaceous borders, says Volvo.

The machine’s operator on that job, Peter Holmberg, reports that the excavator not only performed the same jobs as the more conventional diesel version with equal effectiveness but that the digging feeling was “more pleasant and more precise”. It also provided a calmer work environment, he says, as there was less vibration in the cab, better air quality and a quieter atmosphere that allowed for clearer communication between workers.

Following this debut, Volvo’s electric machine went to a French customer, Spac, part of the Colas Group, for further testing. It was used for digging trenches at the Saint-Nom-la Bretèche golf course, near Paris.

Spac’s operator, Alexandre Birot, said: “When we talk to the guy in the trench we don’t have to yell, we talk normally and he can hear everything. With a traditional excavator we first have to turn the engine off for him to be able to hear. What’s more, when we spend the whole day in the trench, usually he would inhale a lot of fumes but now there’s no exhaust gas for him to inhale. If there were only electric machines in the company that would be amazing.” 

“Zero emissions and lower noise levels is an absolute game changer,” says Ahcène Nedjimi, Volvo CE’s electromobility specialist. “The challenge now is to figure out the best way to charge them in a faster way. That’s something we are working on now.”

He concludes: “The question is no longer when, or if, we will have a shift to electromobility, but how fast it will come. We are really at the tipping point with no point of return. We need to emit less, pollute less and build the world we want to live in.”

Of course, battery-powered excavators are still only zero emissions at the point of use. The machines still have to be manufactured and the lithium for the batteries has to be mined, neither of which is anywhere close to carbon neutral. But these innovations clearly represent advancement.

Users attest to electric digger’s performance

Costain Skanska Joint Venture has been using a JCB 19C-1E on its HS2 enabling works by Euston Station in London.

Site foreman Ben Lennon says: “We’re involved with the demolition and excavation in the Euston area so we’re currently working underneath an encapsulation structure. We wanted to minimise the noise and the fumes so we’re using the JCB electric machine inside the tent.

“There are safety benefits with the electric machine – there’s no noise, there’s no fumes and no emissions – while servicing and maintenance are a lot easier. Also, we don’t have to worry about the fuel. It’s able to do all of the same work that the diesel machines do. I think for an electric excavator JCB have managed to get it right.”

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The machine is on hire from L Lynch Plant Hire, which was involved in the product’s development. Directors Merrill and Rob Lynch describe the 19C-1E as “the leading innovation in the electric machinery market”.

Online discussion about electric diggers has revealed widespread scepticism about manufacturers’ claims on battery life (any mobile phone owner knows that advertised battery life is rarely the same as real life, especially after a few years of use). 

But the Lynches are eager to vouch for JCB here. “We are very pleased with the performance of the JCB electric mini,” they say. “We were also proud to play a part in the evaluation of the model and are delighted that the final design meets hirers’ needs to sustain battery life for a longer working period between charges – indeed it lasts a full seven-hour working day on our applications on just a single charge.”

Sunshine & hydrogen

Solar generators can keep electric diggers emissions-free, while hydrogen fuel cells are already powering some static plant

Solar generators can keep electric diggers emissions free, while hydrogen fuel cells are already powering some static plant
Solar generators can keep electric diggers emissions free, while hydrogen fuel cells are already powering some static plant

One of the obvious drawbacks of electric construction machinery is that you have to have somewhere to plug them in to recharge them. As many construction sites are off-grid, power traditionally comes from a diesel generator. But a battery-powered excavator that needs recharging by a diesel generator immediately loses any claim to virtue. It defeats the point.

One way of keeping electric diggers emissions-free on sites that are off-grid is to use solar generators, like the Solar Pod or the Solatainer.

Solar Pod has been developed by Nixon Hire in partnership with manufacturer AJC Trailers. Nixon Hire wanted an emissions-free power source for its fleet of 10,000 mobile welfare units. It started out last year by putting solar panels on a shipping container and after a series of refinements developed a more compact unit with fold-out wings so two can fit onto a standard truck. 

Over the past year it has built up a fleet of 70 Solar Pods and is aiming to have 200 by mid-2020. “We are struggling to keep up with demand,” says managing director Graham Nixon. There is a waiting list but customers that have already had them on site include Barratt and PJ Carey, he says.

The Solar Pod stores energy from the sun, even on a cloudy day, and releases it as required. One Solar Pod is sufficient to power five site cabins. The solar element will either power the site directly or will assist by charging the battery storage. To cope with peaks of energy demand or troughs of sunlight, it has a 25kV back-up diesel generator inside (along with a 400-litre fuel tank) but evidence indicates it is not needed very much. 

“I’ve had 20 units on a film production site in Essex,” Nixon says, “and during the whole production the diesel generator only kicked in for 5% of the time.” 

This is not a one-off, he says; results from other sites have been similar.

There is also an H20 Solar Pod version, with the added feature of a large water tank.

Solar power is very much the focus of Nixon Hire’s investment this year. The lack of infrastructure investment in the UK and fierce competition in regular plant hire has led Nixon to hold back on building up its plant hire business. In contrast, the company is still getting 90% utilisation for its site accommodation and toilet hire, so most of this year’s £37m capital expenditure is going on growing the solar-powered products side of the business, including solar-powered lighting towers.

Graham Nixon is something of a solar-vangelist – he even has solar panels on the company’s welfare vans to power functions when stationary.

The Solar Pod has been developed by Nixon Hire and AJC Trailers to provide clean power to off-grid sites
The Solar Pod has been developed by Nixon Hire and AJC Trailers to provide clean power to off-grid sites

Having initially developed the Solar Pod to support his hire fleet, Nixon Hire is now making sales (expect to pay around the £40k mark). AJC is looking after UK sales while Nixon Hire is taking them international, exhibiting at the Big 5 trade show in Dubai at the end of November where a Solar Pod will be charging a JCB 19C-1E and a Tesla sports car.

The Solatainer solar generator was originally developed by Gaia Renewables before the business was acquired in April this year by Prolectric, a manufacturer of solar-powered lighting towers. 

The original Solatainer is modelled on a standard 20ft shipping container and delivers up to 25kW of off-grid power. Its array of photovoltaic (PV) solar panels charges on-board lithium-ion or deep-cycle lead acid battery storage. Like the Solar Pod, it has a diesel generator for back-up power. User include Costain, Balfour Beatty and Willmott Dixon.

It was also instrumental (as reported on p9 of our June issue of The Construction Index magazine ) in Colas and Network Rail achieving 97% diesel-free operations on a rail renewal project at Llanwern, South Wales earlier this year. 

The new Prolectric SolarCube is a more compact version of the original Solatainer
The new Prolectric SolarCube is a more compact version of the original Solatainer

Two 25kW Solatainer solar generators replaced conventional diesel generators providing light and heat for seven welfare cabins, including site offices, a canteen, toilets and a drying room – saving 6,000 litres of fuel and more than 15 tonnes of CO2 – during a 14-day project centred around a 72-hour possession over the May Day bank holiday weekend.

Like Nixon and AJC, Prolectric has just recently refined its solar generator to produce a more compact unit for ease of transport. The new Prolectric SolarCube is reduced to 10m3 and promises to at least halve fuel consumption with its AutoMate smart energy management system.

“The environmental impact of running diesel generators all day on a major worksite like Llanwern is absolutely huge,” says Colas Rail production manager Ryan Ballinger. “It’s not just about carbon emissions; our lineside neighbours are very important to us. By using solar harvesting, we’re not polluting their environment with unwelcome fumes and noise.”

He adds: “There’s no doubt these technologies are going to be a complete game-changer and we need to push on to get to a place where using this type of technology is just business as usual.”

Another potential alternative energy source for construction machinery is hydrogen fuel cell technology, which has actually been around for years but has captured growing interest in line with concern about emissions.

The relative merit of hydrogen versus lithium-ion batteries is a topic of much debate. The Toyota Mirai is the world’s first mass-produced hydrogen fuel cell vehicle; Tesla’s Elon Musk, on the other hand, has bet the house on batteries and has been quoted as describing hydrogen fuel cells as ‘mind-bogglingly stupid’. 

Nevertheless, in the construction plant world hydrogen is beginning to be considered for powering static plant, although not yet mobile machinery.

AJC Easy Cabin’s Ecosmart Zero welfare cabins are powered primarily by solar power but, instead of having a traditional diesel generator in support, have a back-up hydrogen fuel cell to eliminate local carbon emissions completely. Water vapour is the only by-product.

Taylor Construction Plant (TCP) is also using hydrogen fuel cells, for lighting and CCTV towers, while visitors to Plantworx 2019 may have noticed Stephill Generators displaying a lighting tower powered by a hydrogen fuel cell.

All three companies, AJC, TCP and Stephill, demonstrated their innovations at an event in Loughborough on 3rd October organised by A-Plant at the premises of fuel cell engineering company Intelligent Energy.

A-Plant sales & marketing director Dave Harris says: “Providing sustainable hire equipment and energy options into the construction and infrastructure market is paramount. As a company we want to reduce our carbon footprint and play a leading role in identifying best practice and reduce emissions within the industry, especially when we consider steps that need to be taken to ensure we contribute to the government’s 2050 zero carbon target.

“Therefore, it’s vital that we collaborate with other industry experts, suppliers and our customers to ensure that we drive changes that will reduce our environmental impact.”

He adds: “The hydrogen workshop was the ideal platform to share our findings and experiences, as well as an opportunity to hear from the hydrogen industry experts and customers such as Balfour Beatty and Costain. Hydrogen fuel cell technology is clean, lightweight and will create greater efficiencies for our customers.”

Intelligent Energy's fuel call
Intelligent Energy's fuel call

Lee Juby, chief sales officer at Intelligent Energy, says: “Hydrogen fuel cell technology is here and available now. Our hydrogen fuel cell modules are proving to be a viable alternative power source to diesel generators and can help the construction industry transition to zero emission power for a sustainable future, addressing environmental noise and air quality. They also provide an opportunity to both reduce operating costs and increase environmental performance compared with the use of traditional diesel generators.”

Juby says that the higher the duty cycle, the more sense fuel cells make over batteries, which is why developments in buses and trucks are moving in the direction of hydrogen rather than lithium-ion.

He says that the wider adoption of hydrogen as a power source for construction machinery has been inhibited partly by upfront cost and partly by limited availability of the fuel. The former is just a question of market education; fuel cell systems may cost more than diesel power to buy but they cost much less to run and are likely to pay for themselves within a year or two.

As to availability, enter JCB heir Jo Bamford, who has set up a new company called Ryse Hydrogen and has secured a contract from Transport for London to supply hydrogen to 20 buses. These will be the world’s first hydrogen-powered double- decker buses and are expected to be introduced on three London routes from spring 2020. 

Ryse’s chief operating officer is Buta Atwal, formerly managing director of JCB Heavy Products. 

Liverpool also has a hydrogen bus project in the works, which will see the creation of a new hydrogen refuelling station at the BOC plant in St Helens.

Bamford introduced Ryse to a fringe meeting of the Conservative Party Conference in October. “We have a very simple vision: to totally decarbonise the entire UK bus fleet by 2030,” he said.

Bamford said: “Whilst there have been great strides in developing electric vehicle technology, we risk overlooking hydrogen as a practical, here and now solution to tackling emissions and improving air quality… Our modelling shows that if you reach scale, fuel cell buses will be cheaper than battery electric buses and 12% cheaper than diesel buses by 2030. And once you’ve cracked buses, you can move on trucks, trains, ships and planes.” And diggers, perhaps.

This article was first published in the November 2019 issue of The Construction Index magazine 

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