Talking about my generation

King diesel is dead; or at least he is rather sick... Long live king electricity!

Actually electric power is not yet king in the lifting world but he is a sturdy and ambitious princeling, growing stronger every day and able to take over more and more of the duties that, till now have been the realm of diesel.

Electricity has been an option for a while, particularly for light lifting: mini-cranes and spider cranes are, of course, offered with cable or battery options.

The ability to operate quietly, and without foul-smelling (and planet-destroying) emissions has given them a huge selling point for tasks in enclosed and public places such as shopping malls. They can work during normal hours, needing only a small section around them to be cordoned off rather than requiring the whole building to be shut during what would otherwise be a profitable working day.

Thus Jekko’s latest machine, the SPX328 released autumn 2022, is powered by lithium-ion batteries and can work up to eight hours with a single charge. And it can operate even while it is being charged, by trailing cable from a standard 220V (110V for the USA) supply. Fast recharge takes about four-and-a-half hours.

But heavy lifting is a different matter. The power required is in a different league. A normal domestic supply, or even a threephase light-industrial system, may be unable to deliver the peak energy that say a tower crane or a crawler with a load of several tonnes will need; and on-board batteries would be prohibitively heavy and bulky, or else would offer very limited service hours before needing lengthy, possibly overnight, recharging. Such was the reasoning just a year or two back; and it seemed very valid at the time.

CHANGING TIMES

But if you want an illustration of how quickly things are changing, consider this. Back in 2018 – all of five years ago – Liebherr gave Cranes Today, this statement: “There are no alternative drive concepts [to diesel] for medium to heavy mobile cranes in the foreseeable future. For smaller sizes, one can imagine an electric drive, but operated by electricity on site ("construction site electricity")... There will be many changes in the logistics sector, but not for construction machinery. In the medium term, we see no alternative to diesel for our industry.”

That was in 2018. In December 2020 – just two years later – they introduced the “Liebherr Unplugged” battery-powered lattice crawler crane. It was the first battery-powered crawler crane in the world, and it was a game-changer. It came – still comes – in 200 tonne and 250 tonne versions: the LR 1200.1 and the LR 1250.1. These cranes have the same structural elements – and the same performance – as their conventional diesel-powered brothers but they emit no carbon dioxide on-site. And if you charge and operate them on sustainablygenerated electricity their entire operation is zero-emission for the planet as a whole.

Might the moral be that in the race to non-fossil-fuel energy not even a company as forwardthinking as Liebherr can see more than 18 months into the future?

That would be not quite fair. A close reading of Liebherr’s statement shows that it is talking about ‘medium to heavy’ mobile cranes being impractical for diesel; and in the world of Liebherr, even its 250-tonne crawler counts as almost a light crane. It builds its smaller cranes at its facility in Nenzing, Austria. Its larger cranes are made in Ehingen, Germany. A more recent technical study from the company sheds more light.

It quotes Dr. Ulrich Hamme, Liebherr’s Managing Director Design and Development. “The ‘smaller’ crawler cranes from Ehingen start with a nominal lifting capacity of 500 tonnes and are designed to act purely as heavy duty assembly cranes,” he says. “In other words, they are at least twice as powerful and twice as heavy as the electric 250 tonne machine from Nenzing. The battery-electric approach cannot be scaled up on a linear basis for these crane sizes.”

LAWS OF PHYSICS

In other words, if you double the size of your crane, you cannot simply just double the amount of your batteries. The laws of physics do not work that way.

Phillip Federle is Head of Crane Vehicle Design at Leibherr. He explains the fundamental problem facing all designers of batterypowered cranes at present: “The amount of energy in lithium-ion batteries is very low relative to their size and weight.

“To deliver the familiar flexibility and performance of a mobile crane using a battery-electric power unit, for example, around 20 tonnes of batteries with a volume of more than 15 cubic metres would have to be fitted on to the five-axle LTM 1160-5.2 crane that we studied as a basis for comparison. That is completely unrealistic.”

A diagram in the report makes the point clearly: to store on a crane the same energy as is contained in a 750-litre tank of diesel you would need 21 times the volume and weight of lithiumion batteries. The crane could not carry it. (See graphic opposite.)

But Liebherr is far from giving up. Since that first introduction it has been advancing their portfolio. “Today we provide four batterypowered crawler cranes in our ‘unplugged’ range, the LR 1130.1, LR 1160.1, LR 1200.1 and LR 1250.1 unplugged. The batteries for them are Li-ion NMC (nickel manganese cobalt) technology.” (The additional metals on the cathode tweak and improve Li-ion capacity.) “The cranes’ performance in ‘unplugged’ operation allows for erecting the boom and jib, for travelling a distance of approximately 650 metres with full counterweight or for approximately eight hours of crane operation. All models have the same performance as the conventional versions,” says Liebherr marketing manager Griesser Gregor.

But those big, heavy batteries do not actually always have to be carried on the crane. “External battery packs for cable power supply as an alternative to mains power are also conceivable for use on small mobile cranes,” says Federle. “It may be possible to meet the demand for ‘local zero emissions’ on larger cranes using buffer battery storage devices.” As indeed is already happening for tower cranes. The average construction site uses tower cranes, and here is where some of greatest savings in CO2 emissions could be made. Buildings and the construction industry account for 39% of global carbon emissions. 28% is from the materials – concrete is a huge emitter of CO2; but the construction of those buildings – the cranes, excavators, earthmovers and the like – emit the remaining 11%. Here is the low-hanging fruit ripe for electrification.

To power a tower crane by electricity there are two main options: mains current, via cable; or battery power. Both have disadvantages. Let us look first at batteries. Batteries do not make power. They store it. They have power fed into them at one time or place; and later, in the same or another place, they release it. They are energy storage solutions.

STORAGE SOLUTIONS

Storage is the Holy Grail of renewable energy. Anyone who can find an efficient, compact, and affordable way of storing the intermittent energy that we get from solar, wind, tidal or waves will become immensely rich, and would save the planet into the bargain.

Batteries are a partial, but only a partial, solution. As we have seen, they have a problem. Weight for weight, compared to diesel, they do not store very much energy.

Technology has progressed. We now have lithium-ion batteries and variants of them, and Ni-Cad (nickel-cadmium) as well as the traditional lead-acid. Each has its strengths and weaknesses.

Two or three phrases are key here. One is energy density. Another is power density, which is not quite the same thing. There is charging rate; and yet another consideration is discharge rate. And since in these applications they are operating at the edge of the current technology, extracting every last fraction of efficiency from a battery is key. Hence Battery Management Systems, or BMS, are another vital component. They regulate the rate of charging and discharge, which in turn affects your battery’s longevity and cycle-life. Battery Management Systems optimise these.

Your mobile phone is powered by a lithium-ion battery, and it works well for that. But Li-ion batteries does not work well at low temperatures. They may need heating circuits in winter, which is a waste of the energy they are supposed to be storing. They are also hazardous: they are liable to overheat and catch fire. (You may remember incidents of li-ion batteries fitted to the Boeing Dreamliner self-igniting when that aircraft was first introduced, causing the entire fleet to be grounded.) Even so, their energy density is the best available.

Battery problems might seem to be eliminated if you can plug your crane by cable directly into the mains supply – and for tower cranes that has been a well-used solution. They tend to operate in city sites. Cities such as New York were early introducers of restrictions on diesel emissions; and in a city mains grid power is available close to hand. So plug in your tower crane; problem solved. But not, alas, always.

“Tower cranes take very little power when you average out their consumption over the days of a construction project,” says Gil De Backer. He is business development manager of Belgian scale-up company Neargrid Solutions. “But those cranes are very uneven in their consumption. In the short periods when they are lifting heavy loads their consumption peaks: they need a lot of power just then. And many city locations have grid power that is just not enough to supply those peaks.”

There is a conventional solution: “Normally in the past and still today, construction companies use on-site diesel generators to power their electric tower cranes.” If that seems a perverse, indeed nonsensical, way of reducing diesel emissions, it is. Happily there is now a better solution.

GREEN SOLUTION

“We provide an ecological green alternative for that,” continues De Backer. “We have a battery system that replaces the generator. We supply battery blocks, with high-power inverters coupled to them, and all the safety equipment and battery management systems installed around them to make each one a completely integrated system to plug and play on a construction site.

“The battery block is really focussed on being a replacement for those diesel gensets. It has the same usability, the same functionality as the genset, it does not require any additional on-site knowledge of electricity to handle our system. It is really customercentric,” he says.

One use for the battery system is on sites where there is grid electricity but not enough for a tower crane. “Often on such sites there is some power available – perhaps there is a normal residential grid connexion in the next street. What our batteries do is make the best use of that. We take that small local connection – say between 16-amp and 63-amp three-phase at 400 V – and we connect it to the inlet side of a battery system. So it will always be trickle-charging our system throughout the day and night. And such a connection actually has enough energy when you average it out. Our battery acts as a buffer, delivering its reserves of energy to the crane at times of peak load demand, then recharging itself the rest of the time.

“We have two systems: the ‘Boost’ can power one crane and weighs 3.1 tonnes; so it is placed next to the crane, and can be positioned by a large forklift or by a mobile crane. The ‘Force’ can power three cranes and weighs only 4.1 tonnes, so it can be delivered and positioned in the same way.”

Even when there is no mains grid at all on-site to deliver the trickle-charge, the system can still be useful. “It is also possible to use a small diesel genset to charge the battery block. On a construction site with two cranes, you would normally have two 200 kVA gensets next to each crane. We can reduce that to a single 60 kVA genset, running perhaps all day, with our battery pack in between them. And that will clearly make fewer emissions and lower consumption than a big generator working intermittently.”

And what, exactly, is inside the Neargrid battery pack? If you guessed a lithium battery you'd be wrong. It is old-fashioned lead-acid – and for very good reasons.

“It is a design choice that we that we made. One of the capabilities of lead acid is that you can reach a very high discharge current from a rather small capacity. We are really a provider of peak power, not necessarily a provider of big energy loads. So for us it is important that we can deliver the high power spikes and that we can do that from a very compact battery pack. If you wanted to have the same peak output power from Li-ion you would need a battery pack that was double the size.

“ Of course lithium ion battery has more energy available, but it cannot release it so quickly.

“Lead acid is less expensive. And it is a proven known technology that is very safe. If on your construction site you had a lithium ion battery bank and you bumped into it with a forklift you could have thermal runaway of your battery pack and a fire that would be very hard indeed to extinguish.”

There is even more: “With leadacid we do not need complicated battery management systems to keep the battery in good condition. We do not need active cooling – the system does not need it. We just have a forced airflow. And transporting and handling lithium ion has more constraints than with lead acid.”

So electric power is a matter of horses for courses. Different applications need different solution: cable and the all-singing all-dancing high tech of Li-ion are there; but so is the old dependable lead-acid battery that starts your old-fashioned internal combustionengined car each morning. Other solutions will doubtless come. The essential is to get away from diesel.

All mammoet SpMTS can now go electric

It was Mammoet who back in 1984 claims to have invented the SPMT or Self Propelled Modular Transporter. They are now the default for moving heavy and oversized loads. More than 40,000 axle lines are in use globally; they are driven, of course, by diesel powertrains inside the trailers. But Mammoet can now offer a zero emission option for SPMT transport; the option is a retrofit compatible with any trailer in its fleet.

The diesel powertrain within the power pack unit (PPU) is replaced by a battery-powered electric alternative. Each unit has all its batteries contained within the existing PPU envelope and, once fi tted, each trailer combination has comparable power to existing industry standard units.

Battery charging, from an AC supply, normally takes fi ve hours from empty to full; this can be reduced to around two hours by a unique ‘recharging’ technique which uses hydro-electric converting. Dependent on usage the power pack units will last four to fi ve days before recharging is required. The start-stop system which is included works very effi ciently due to the nature of the power from the electrical system.

Electric operation vastly reduces noise levels at project sites, resulting in a safer and more productive work environment. Communication between staff is clearer, while at locations where sound restrictions are in place longer operational windows are now possible.

More importantly, the system represents another step towards achieving zero emissions on site.

This solution was part-financed by the DKTI, a Dutch government programme to develop climate technologies and innovations in logistics. As Mammoet points out, retro-fi tting existing SPMT fleets, rather than sourcing brand new replacements, cuts down on both waste and additional fabrication.

Tadano reveals evolt rT

At this year’s CONEXPO in Las Vegas Tadano showcased the prototype for the GR-1000XLL EVOLT, the world’s first battery electric rough terrain crane, which Tadano announced would be launched in 2024, first in the USA and in Canada with additional markets to follow.

The GR-1000XLL EVOLT can travel to work sites and take care of all lifting operations there exclusively with energy supplied by its batteries, making fully zero-emission operation possible.

A single battery charge is enough for up to nine hours of on-site crane operation, or fi ve hours of crane operation with a travel distance of up to 12.5 miles (20 km). Battery capacity is therefore enough to cover an entire typical workday for this crane model. Integrated regenerative braking lengthens both the running time and the range.

SHORT CHARGING TIME

Tadano says its engineers are proud of the short charging time that they have achieved: it takes just two hours using fast charging on a US-COMBO CCS1 connection, and about seven hours with normal charging on a three-phase 240 VAC, 100 A commercial supply. Unlimited operation with the crane plugged into a power outlet is available as well.

The crane’s lifting performance is exactly the same as that of its diesel-driven counterpart, the GR-1000XLL-4. The electric motor delivers 194 kW, giving a top speed of 11.2 mph (18 km/h). Its dimensions are exactly the same as those of the GR-1000XLL-4.

“This crane will make an invaluable contribution to achieving our goal of reducing the CO2 emissions from our products by 35 percent by 2030,” says Toshiaki Ujiie, President and CEO of Tadano.

Tadano calculate that the electric-powered GR-1000XLL EVOLT will deliver annual savings of around 2,200 gallons of diesel, resulting in a reduction of more than 24 US-tons of CO2 emissions for an average crane usage scenario.

Tadano has also announced the 25 tonne class GR-250N EVOLT rough terrain crane, which is scheduled for launch in Japan later this year. It is an electric sibling of the conventionally-powered GR-250N. The electrifi cation of the machine was based on tech demos with which Tadano developed and tested solutions for a market-ready, fully electric crane that would be suitable for real-life use. This powerful and extremely fast 194-kW machine is the fi rst commercial crane to come out of that process.

Again, the battery can sustain a mix of work and travel: up to 11 hours of operation at the worksite or, for example, 25 miles (40 km) of travel followed by fi ve hours of operation; again work is possible in plugged-in mode.

Battery-powered tower cranes in London

Ampd Energy, a player in the energy storage industry, in collaboration with Select Plant Hire, a subsidiary of Laing O'Rourke, has deployed three of its zero-emission ‘Enertainer’ lithiumion battery energy storage systems at London's high profi le Olympia Redevelopment.

Ampd Energy says that its modular lithium-ion battery solution has the potential to revolutionise the industry by electrifying building sites and driving down carbon emissions.

The deployment of the Enertainer systems at the Olympia Redevelopment is estimated to save 192 tonnes of carbon over 12 months, reduce operating costs by 70%, and eliminate the equivalent air pollutants of 975 cars when compared to standard diesel generators.

Ampd Energy claims that, over the life of the project, the Enertainer will be more cost effective than diesel generators, as well as saving space and labour time.

According to Ampd Energy, compared to fossil fuel generators the Enertainer reduces carbon footprints by up to 90%, is up to 30 times quieter, emits zero air pollutants, and eliminates diesel handling and usage risks. It requires minimal maintenance and zero refuelling downtime.

According to Ampd Energy, the Enertainer is the fi rst energy storage system in the UK to power such large construction equipment and, with the partnership with Select, the battery system is now available across the UK.

The company already has 130 Enertainer batteries in use across building sites in Hong Kong, Singapore, and Australia.

“We are proud to have launched our fi rst European deployment for the Olympia Redevelopment,” said Brandon Ng, CEO and co-founder of AMPD Energy. “This is a fantastic opportunity for us to demonstrate the Enertainer’s compelling environmental and commercial impacts, right here in London.”

uK firm Falcon Cranes presents the voltpack from Northvolt

UK tower crane supplier Falcon Cranes has launched the Northvolt Voltpack, a modular and scalable energy storage system designed to power cranes and other equipment on construction sites. Northvolt is a battery cell manufacturer headquartered in Stockholm, Sweden.

The Northvolt Voltpack is made up of individual battery modules that can be combined to provide between 281kWH and 1,405kWh of power. The system works by storing energy from a mains supply or renewable sources in a battery. This stored energy can then be used to power cranes and other equipment on construction sites, reducing the need for diesel or petrol generators. Falcon says the Northvolt Voltpack offers a cleaner and more sustainable way to power cranes and other equipment on construction sites. By reducing the use of diesel or petrol generators, the system can help construction companies reduce their carbon emissions, meet their sustainability targets, help save on fuel costs and reduce noise pollution.

Falcon Cranes will be using the Northvolt Voltpack to power their cranes and other heavy equipment on construction sites across the UK. The company is confi dent that the Northvolt Voltpack will help it improve effi ciency, reduce operating costs, and provide a cleaner and more sustainable way to power its cranes.

The charging time for the Northvolt Voltpack depends on the size of the battery module and the charging infrastructure but it typically takes four hours to fully charge the battery on a 125amp supply.