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Wide range of zero-emission technologies reduces the most emissions, says Frontier Economics study

A mobile crane drives down a road
A Liebherr LTM 1160-5.2 mobile crane

The consulting firm Frontier Economics has conducted a life cycle analysis of greenhouse gas emissions of typical construction machines equipped with various drive technologies for the Liebherr Group. The consulting firm determined how much CO2 arises from production to operation through to the recycling of the machines.

The aim of the analysis was to calculate the emissions of the machines and their drives in order to be able to recognize and assess how greenhouse gas emissions can be most effectively reduced. It is important to look at the overall life cycle of the machines for this analysis. This ranges from the mining and transport of the raw materials to production and the actual operation of the machine to the disposal and recycling.

"Emissions analyses are generally limited to the operating phase. This is not enough for our products because greenhouse gas emissions also occur in the upstream and downstream phases of construction machines' lifecycles," says Stephen Albrecht, member of the board of directors of Liebherr-International AG. "To get a complete picture, we examined all stages of the life cycle, including the production of energy and provision of the infrastructure."

These results are combined in a product carbon footprint, which describes the emissions of a product throughout the entire life cycle.

Dedicated zero-emission technologies for specific applications

The study examined three types of construction machines: mobile cranes, truck mixers, and wheel loaders. As evidenced by the collected data, the three types require different drive technologies in order to reduce as much emissions as possible due to their different performance requirements. For truck mixers, electric drives make the biggest contribution to emissions reductions provided they use one hundred percent renewable electricity for charging. For mobile cranes, operation with hydrotreated vegetable oil (HVO) shows the biggest savings potential. It is important that the HVO is certified to be produced from plant and food waste, for example, and does not contain palm oil. Hydrogen made from CO2 neutral sources follows in second place. In the long term, operation with hydrogen seems optimal as the availability of HVO in the vast quantities required cannot yet be predicted. Until the required hydrogen infrastructure and drive technologies are mature, HVO delivers the best results as an interim technology, particularly in existing fleets with combustion engines. Wheel loaders should be operated either with a battery-electric drive charged with renewable electricity or with e-fuels.

"The results of the life cycle analysis show that there is no uniform solution for climate-neutral drives of construction machines," adds Albrecht.

Liebherr, therefore, has started to rely on a technology-neutral approach and can help reduce emissions as much as possible depending on the machine and the application.

A look at the Liebherr product portfolio, which includes 13 product segments, illustrates what leads Liebherr to compare various drive technologies. The smallest machines have a power output of 30 kW, the largest have a power output of more than 3,000 kW. All these machines must perform reliably in completely different conditions and applications.

"A wheel loader on an urban construction site, for example, is exposed to different conditions than a mobile crane used in the construction of wind turbines," says Albrecht. "The former can often be powered by electricity. In contrast, infrastructure projects in rural areas often lack the necessary power supply for an electrical connection. In addition, more energy is often required than can be provided with a battery-operated electric drive."

Thinking about reducing global emissions

Liebherr engineers work with a wide range of climate-neutral fuels and drive technologies from certified hydrotreated vegetable oil (HVO) to e-fuels made from green electricity, water, and CO2; battery-electric drives and hydrogen drives; hydrogen combustion engines or hydrogen fuel cells. At the moment HVO is interesting for the company because it is an already available, interim technology. It has the advantage that it can be used in older construction machines with diesel engines. These machines are often in use even longer in many regions of the world – and continue to cause emissions there. Emissions can also be reduced significantly with HVO as a diesel admixture – a further contribution to reducing climate change.

A diverse zero-emission technology approach

Based on the results of the life cycle analysis, Liebherr wants to adopt a technology-neutral approach in the construction industry.

"Effective climate targets and incentives for the construction machinery sector must enable technological diversity so that the most environmentally friendly technology can be used depending on the performance requirements," adds Albrecht.

Because of this, battery-electric technology should not be viewed as a universal solution, but as one important technology in the future drive mix. Apart from electric drives, it is just as important to closely monitor the topic of hydrogen. The regulatory conditions for producing hydrogen and e-fuels, which are made from renewable sources, must also be established. After all, the interaction of all these technologies allows optimal solutions to be created for all application scenarios in the construction machinery sector.

Electric excavators and cranes from Liebherr 

Research and development work is already making progress. For example, Liebherr's program already includes several construction and mining machines with zero-emission drive technology. One of around ten electric crawler excavator models is the crawler excavator R 976-E, which is supplied with electricity via cable. The excavator's drive system produces little noise during operation and zero local emissions. The all-electric truck mixers, the ETM 1005 and ETM 1205, have batteries that are charged between travel to and from the job site or overnight. Another example is the LR 1250.1 unplugged battery-operated crawler crane. The machine can be operated on-site either with a conventional electrical connection or without a cable – with no reduction in performance compared to the diesel model.

Liebherr also promotes the use of HVO in its factory in Ehingen, among other places. Since September 2021, all new mobile and crawler cranes produced there are filled with one hundred percent HVO before delivery to customers and are also operated with HVO for on-site crane acceptance tests and test drives. The Liebherr factory in Kirchdorf a. d. Iller has followed suit. HVO is used for the first filling and acceptance tests of earthmoving and material handling machines since January 2022. The factories' internal logistics are also changing over to the climate-neutral fuel.

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