Ongoing development of all power systems
What future technologies will power fork lift trucks and material handling equipment? As new technological solutions offer considerable advantages, this is a key question for many engineers and designers. They can be employed to increase the safety and productivity of vehicles and for more efficient management of processes. At the same time, however, the potentials of established power systems have not yet been fully explored. Linde Material Handling is actively pursuing new developments in all areas.
The current situation can be compared with the automotive industry: various alternative power concepts for material handling vehicles compete with conventional technologies that each have their own clear advantages. Ultimately, the decisive factor is where and how the vehicles are deployed.
Different market developments
For example, increasing numbers of electric forklifts are now deployed in what were previously the exclusive domains of their gas-powered or diesel counterparts. Not only as replacements for smaller vehicles – Linde has offered E-forklifts for loads of up to eight tonnes since 2014. Correspondingly, demand for vehicles powered by rechargeable Lithium-ion (in short, Li-ion) batteries is currently growing not only in the warehousing segment. They can be charged much faster than conventional lead-acid batteries, have a much longer service life, have a higher power density and require no maintenance. Fuel cell powered material handling vehicles are widespread in the USA and have the particular advantage of refuelling times of only a few minutes. Both systems share the common advantage of being electronically controlled. This allows precise documentation of charging histories and maintenance status. For example, charging processes can be controlled and monitored by IT systems – one of the preconditions for Industry 4.0 solutions.
Despite this, many users continue to rely on drive systems powered by conventional lead-acid batteries, primarily due to the higher procurement costs for alternative power concepts. Cost-effective operations with such vehicles cannot, however, be realised in every operational scenario. The more intensively they are used, the more economical they are –for example in multi-shift operations. With this in mind, Linde actively pursues the development and advancement of all past, current and future power system technologies. Ultimately, the experts always work towards the same goal – to provide the customer with the most productive overall system and the charging or refuelling infrastructure it requires.
Linde also supports customers in the assessment of the sustainability of the respective power systems. With the aid of a certified eco-balance methodology, the environmental impact of a product can be assessed for its entire operational life cycle.
The comparison between the battery types is impressive in every respect. For example, the charging process: while the Li-ion batteries utilised by Linde take only 1.5 hours to charge to full capacity, the charging time for a comparable lead-acid battery is around eight hours. The charge itself is different, too: batteries with Li-ion can be discharged to a level as low as two per cent, while the residual charge in the case of the lead-acid type is up to 20 per cent. What’s more, lead-acid batteries can withstand only around 1,250 charging cycles without detrimental effects. After this, their charge retention level falls to 50 per cent. In the case of Li-ion batteries, twice the number of charging cycles is possible without any significant loss of performance. At the same time, the charge retention level remains at a respectable value of 75 per cent. Li-ion batteries bring enormous cost benefits due to significantly longer replacement intervals.
Danone: an example of ideal connectivity
Some further advantages of Li-ion technology are illustrated by this case study of their use at the ‘La Sablonnière’ facility of the French food processing concern Danone in Normandy. One of the main reasons for their use there is their ‘connectivity’: The material handling vehicles are equipped with an interface that enables communication between the battery and the forklift. When the charge level gets lower, the vehicle automatically reduces its performance level and completes its assigned shift without having to stop for top-up recharging. Similarly important is the very precisely measurable residual charge level of the Li-ion battery. For example, one of the material handling routes serving the Danone facility operates for exactly 15 minutes of every hour. In the waiting time between routes, the vehicle stops briefly at a recharging station – a perfect exploitation of time and resources.
Faster refuelling – a clear consequence of this, and a significant advantage in multi-shift operations, is the significantly increased operational readiness of forklifts and tow tractors. In addition to this, the braking energy of Linde vehicles is recuperated and stored in the Li-ion battery of the hybrid system and released again under peak loads. Basic power requirements are fulfilled by the fuel cell. Further advantages are that battery replacement is just as superfluous as keeping stocks of spare batteries and the installation of bulky recharging stations. A basic precondition is, however, the availability of a hydrogen supply infrastructure.
Cost-effectiveness confirmed by case study
A comprehensive study of the cost-effectiveness and technical potentials of this technology was jointly conducted by the BMW Group, Linde Material Handling and the Materials Handling, Material Flow and Logistics Institute of the Technical University of Munich (TUM). Material handling vehicles powered by hydrogen fuel cells were deployed in the body production facility of the BMW i plant in Leipzig – for a period of over 20,000 working hours. The verdict: the jointly developed, hydrogen-fuelled power train concept for material handling vehicles is already a marketable proposition and a cost-effective solution when certain preconditions are fulfilled. In summary, the high availability of the technology and its utilisation of regeneratively produced hydrogen gas was rated highly for its low environmental impact.
Focus on hydrogen production
Just how environmentally friendly is the production of hydrogen gas? Up until now, the gas was predominantly a by-product in the chemical industry and was generally utilised for other purposes on site. A large proportion is also generated in the processing of natural gas. There are, however, alternative methods. For instance, climate-neutral biomass is already utilised in the so-called thermochemical conversion process to produce hydrogen and carbon monoxide. Basically all that is needed to produce hydrogen is water and electricity, the latter can, for example, be generated by wind power or solar panels. Large-scale electrolysis plants could then produce hydrogen with zero environmental impact from CO2 emissions. Experts estimate that the general significance of hydrogen as an energy source and, with this, the production of ‘green hydrogen’, will increase in the next few years.
Convincing research results
Linde has already conducted two extensive research projects on the use of this technology with various partners. In addition to the previously mentioned trial at BMW, a second pilot project was conducted at the DB Schenker cargo handling centre in Hörsching, Austria. A hydrogen refuelling station was installed at both locations. The results were identical: the hydrogen supply infrastructure operated without problems from the start, vehicle downtimes remained at the same level as for battery-powered vehicles and drivers accepted the new technology without misgivings. Interesting here is the measured ecological balance in Hörsching – the hydrogen for this project was generated by the thermal conversion of biomass: In comparison with vehicles powered by lead-acid batteries recharged with electricity from the EU power mix, the greenhouse gas emissions sank by around 75 per cent.
Read more in Linde's Sustainability Report
Linde analyses the ecological balance
Just how environmentally friendly are forklifts, stackers & Co.? Linde customers who perform their own environmental audits receive the hard data they need for the optimisation of their environmental strategies. In collaboration with the Fraunhofer Institute for Building Physics (IBP), Linde Material Handling devised a method for quantifying the environmental impact throughout the life cycle of its forklifts and warehouse equipment. The quantification process covers all phases of the product life cycle – from raw materials extraction and the manufacture of individual components to transportation and the operational lifetime to the recycling of vehicle components. All significant effects on the environment, such as water usage, greenhouse emissions, air and ground emissions etc., are taken into account. Linde integrates the insights gathered into future design and development processes. The TÜV-certified methodology also enables extremely precise analysis of the effects of customer-specific configurations or the replacement of individual components. This methodology was employed in the H2IntraDrive project for the assessment of sustainability issues in the utilisation of fuel cell powered vehicles.
Mark Hanke, head of Components Predevelopment at Linde Material Handling, talks about the opportunities and possibilities that fuel cells offer as the drive system for industrial trucks
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