Energy systems for economically sustainable intralogistics
Hamburg, September 29, 2021 – Lead-acid battery, lithium-ion technology or fuel cell? If you want to operate economically and efficiently, you have to identify the energy system that is suitable for your particular transport processes. This decision depends on many factors and therefore requires a high level of experience. During yesterday’s “Energy” webinar, the intralogistics and energy experts from the Hamburg-based intralogistics provider STILL provided a comprehensive overview of the different energy systems and explained the advantages and disadvantages of each system in a practical and clear manner.
The topic of energy is becoming increasingly important in intralogistics. The European Union aims to achieve a climate-neutral economy by 2050 at the latest – Germany wants to reach this goal much sooner. This means that CO2 emissions must be avoided as far as possible or stored to the same extent as they are emitted. In order to achieve this goal, the EU Commission and the federal states are now making it their duty, through laws and regulations, for everyone to make their contribution. For example, by means of a high CO2 tax, with expensive emission certificates and with a complete ban on combustion engines, which would make electric drive mandatory for every type of vehicle from 2030 at the latest.
In addition, consumers are also becoming increasingly sensitive to the climate neutrality of services and products. For this reason, too, companies are increasingly making sure that their supply chains meet sustainability requirements. For example, suppliers must provide certificates on the origin of raw materials, production conditions and the carbon footprint. A good ecological balance sheet is thus increasingly becoming a competitive advantage.
The search for the appropriate energy system
In any case, the following applies throughout Europe: energy is precious and becoming ever more precious – and therefore the consumption and use of energy must be managed intelligently. In intralogistics, this begins with the selection of the appropriate energy system for driving industrial trucks. The current choices are lead-acid batteries, lithium-ion technology or fuel cell systems. But no matter which system you choose, that decision will have an impact. On the infrastructure of warehouses and production facilities, on the choice of transport systems, on operating costs and ultimately on the size of the investment. “Each of these energy systems has its own specifics and requires certain prerequisites in handling,” explained Dyrk Draenkow, product manager for energy systems, during yesterday’s webinar. To arrive at a sustainable and economically efficient decision, he says, the big picture must be considered: the transport processes, the desired handling performance, the type of vehicles and, of course, the infrastructure of the warehouse.
According to Björn Grünke, also product manager for energy systems, there are therefore five criteria that can be used to identify optimally suited systems for the respective requirements: vehicle availability, consideration of the infrastructure, acquisition and operating costs, and future security. In this consideration, lead-acid batteries come to a rather moderate overall result, according to the expert. While their performance in terms of vehicle availability is mediocre, they are not at all convincing in terms of infrastructure due to their high storage space requirements. By contrast, they are right out in front when it comes to investment costs. Compared to all known energy systems, the lead-acid battery has a very low purchase price of around 150 euros per kilowatt hour. However, this plus point is offset by the system’s only moderately efficient operating costs. And when it comes to future-proofing, this energy system can only partially convince the STILL experts. “This technology is exhausted. No further developments towards significantly shorter charging times or higher power density are to be expected,” said Dyrk Draenkow, adding, “However, if we disregard the limitations described, this type of battery will remain a reliable and very usable energy system for years to come. It is especially suitable for those users who have only a few vehicles to work with.”
Lithium-ion batteries can be temporarily charged at any time – and within a very short time, without damaging the battery or shortening its service life. This enables flexible use of the vehicle, around the clock, without the need to change batteries. Lithium-ion technology thus ensures maximum availability even in multi-shift operation. In terms of charging time, experience shows that charging for one hour means driving for up to three hours. In addition, this energy system places very few demands on infrastructure. The situation is somewhat different when it comes to investment costs: Because lithium-ion batteries still have a purchase price that is about two to three times higher than lead-acid batteries. “However, lithium-ion batteries have at least twice the service life for the same capacity. If you look at the general price development of lithium-ion cells since 2010, the direction is clear: It is getting cheaper and cheaper,” says Björn Grünke. The system also scores points in the area of future-proofing. Charging options as well as control options to increase efficiency are constantly being developed further, while at the same time reducing the acquisition costs for the system.
Fuel cell systems
The special feature of this energy system is that the electricity is generated in the vehicle and no longer comes from the socket. Dyrk Draenkow: “When we talk about a fuel cell in intralogistics, we mean a so-called Battery Replacement Module. This corresponds to a specific battery trough in terms of size, weight and shape. This means that an existing lead-acid or lithium-ion battery can be replaced one-to-one by this module. All the components required for the fuel cell are assembled in such a module.” A so-called complete system first contains the fuel cell itself, the so-called stacks. These convert the energy stored in the hydrogen into electrical energy. This energy is used to charge the integrated lithium-ion battery, which supplies the vehicle with constant power. The system also includes a high-pressure hydrogen tank with tank nozzle and other components.
Since the system does not need to be recharged, but refueled, there is no downtime at chargers or power outlets. After only two to three minutes at the hydrogen filling station, the vehicle is available again at full capacity. This creates maximum flexibility in terms of operating times and allows heavy-duty applications or even multi-shift operation without restriction. Experience shows that one tank of fuel can provide up to eight hours of use, depending on vehicle type and usage.
However, the hydrogen required must be delivered by tanker truck. Or you can make yourself completely independent and produce the hydrogen yourself with your own electrolyzer on the premises. However, additional power is required for this. If you don’t want to emit any CO2, you can produce the “green” energy yourself: with wind turbines or photovoltaics. Since this involves a certain amount of effort, fuel cell technology can only be rated as moderately suitable for the infrastructure criterion. This also applies to the investment costs: On the one hand, a “fuel cell ready” vehicle must be purchased from scratch, and on the other hand, costs are incurred for the acquisition of the appropriate fuel cell system. These costs are four to five times higher than the price of a lead-acid battery. High investments are also still required to create the necessary infrastructure, so that it is currently hardly possible to use fuel cells for vehicles economically. However, funding programs at national and European level will help to make the business case “green” in economic terms in the future. Subsidies are available for both vehicle equipment and infrastructure. Says Dyrk Draenkow, “Basically, economies of scale apply to the future of fuel cells: the more hydrogen consumers there are on the store floor, the faster the cost per kilogram of hydrogen can be reduced.”
The efficiency of an energy system always depends on the particular application – unfortunately, there is no such thing as a system that fits all applications. Guidance in this very confusing situation is provided by the intralogistics and energy experts from the Hamburg-based intralogistics supplier STILL, for example during yesterday’s webinar(www.still.de/webinar). But even beyond that, they are always available to provide advice and support to companies facing an investment decision.