CRANE BATTERIES Ӏ POWER GENERATION


brothers but they emit no carbon dioxide on-site. And if you charge and operate them on sustainably- generated 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 forward- thinking 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 battery- powered 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 lithium- ion 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 battery- powered 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


CRANES TODAY 25


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 retrofi t compatible with any trailer in its fl eet. 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-fi nanced by the DKTI, a Dutch government programme to develop climate technologies and innovations in logistics. As Mammoet points out, retro-fi tting existing SPMT fl eets, rather than sourcing brand new replacements, cuts down on both waste and additional fabrication.


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