Three factors dominate all forklift operators today – economics, safety and the environmental issues and in the choice of motive power all three will be influenced by technical and legal changes to come. Environmental legislation, like the Energy Act 2011, and technical advances in the trucks’ motive power are likely to see a serious change in the choice of motive power over the next 10 years. While there are three basic forklift power sources, diesel, gas and electricity, the option range will rise sharply, along with the complexity of calculating their real impact on the environment, about which there may be considerable confusion.
In sensitive areas like food and pharmaceutical manufacturing, electric trucks are almost always the truck of choice because of their zero toxic emissions. That is likely to remain so for some time but in the bigger picture LPG-powered trucks produce less CO2 than electric trucks, unless the electricity generated is from a totally clean source like hydro. The Carbon Trust, for example, found that LPG produced 0.214 kg CO2 per KWHR whilst electricity produced 154% more CO2 and diesel produced 18% more than LPG. The same problem currently occurs with hydrogen fuel cells, an energy source entirely clean at point of use but far from clean at point of production.
The choice of motive power can influence the choice of truck because the fuel type chosen affects the overall purchase and running costs of the truck. LPG trucks, for example, tend to be cheaper to buy than both alternatives and they are significantly cheaper to run than electric, which require costly recharging units and often standby batteries in multi shift work. As LPG is cleaner than diesel it means less wear and tear on LPG engines, bringing significant savings on maintenance and replacement parts. Compared with electric trucks, LPG machines are much quicker to refuel, involve less safety considerations and are operational 24/7. Performance is more consistent with LPG as they easily cope with steep and uneven terrain, not to mention climatic challenges, and are immune to electricity power cuts. But for an even cleaner gas-powered truck there is compressed natural gas (CNG) which is entirely free of the carcinogen, benzene.
New fuel sources being seriously considered and variants of existing ones may shift the preference from one fuel type to another but there is much disagreement within the industry over their adoption and their time frame, and that applies to hybrid trucks. Hybrids have produced significant cuts in fuel consumption when combining diesel with lithium-ion batteries, like Mitsubishi’s Grendia Ex range, but they rely on at least two energy converters or motor systems and that means doubled costs and maintenance and service and more stringent safety requirements.
Within the electric camp there is much buzz about the prospects for Li-ion batteries compared with lead-acid batteries. The former can be charged in only 20 minutes as against eight hours for lead-acid. The lifetime for Li-ion is three times that of lead-acid, requires no maintenance and can be re-charged at any time. However, Li-ion costs about nine times as much as lead-acid batteries and their lack of weight precludes them from present designs of counterbalanced forklifts. But Li-ion battery prices are likely to fall sharply with any serious growth in demand.
Any exercise that considers the environmental impact of fuel choice for forklifts must take a holistic view and that means looking at renewable and recyclable issues. Not all gas forms are come from finite fossil fuels. Methane gas, for example, can be made from waste food by anaerobic digesters. The concept of extracting methane gas fro rubbish tips is far from new and has been used to power a paper mill, while at the same time reducing the niffy nuisance for householders living nearby.
The future will almost certainly see the decline of diesel powered forklifts but less clear is which fuel source will rise through the ranks to hegemony.
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