Does diesel fuel have a future in the materials handling industry?

As electric forklift trucks continue to increase their share of the materials handling market and interest in renewable energy grows, is diesel power heading towards extinction?

According to Mark Nicholson there is good reason to believe that diesel will always be part of the world’s overall energy mix.

For many applications a diesel lift truck is a better choice than a battery powered alternative, and you may be surprised to learn that in some cases diesel actually offers greater environmental sustainability than electric.

Diesel advantages

Where electricity is not ‘green’ 

In an area where electricity generated by solar, wind, hydro or other renewable energy sources is not available, the total emissions resulting from use of an electric truck are greater than those from a diesel. The electric truck itself is non-polluting but you have to consider the amount of coal, gas or oil burnt to generate the electricity that charges its battery.

Bear in mind, too, that converting energy from one form into another is wasteful. When the energy in fossil fuels is converted into electrical energy, much of it is lost in the form of heat. When current electricity is converted to static electricity in the battery there are similar losses. By contrast, diesel powers an engine directly. The same arguments apply to trucks powered by hydrogen fuel cells, as electricity is needed to produce the hydrogen.

Where long life is important 

The structure of industrial diesel engines is extremely robust and the fact that they are designed to work at low revs makes them even less vulnerable to wear. Owners can expect a diesel truck to have a long life, to require minimal maintenance and to retain a good residual value. This makes economic sense and is also good for the environment, as it reduces the amount of raw materials consumed and the necessity for waste disposal.

The power of a diesel forklift is constantly ready to use, allowing 24/7 operation with just a few minutes of downtime if a fuel top-up is needed.

Where strength is a priority 

A diesel truck usually offers more powerful performance than a comparable electric truck, giving higher torque, gradeability, acceleration and lift speed. For the heaviest loads, diesel power is usually indispensable.

Where trucks need to work non-stop 

The power of a diesel forklift is constantly ready to use, allowing 24/7 operation with just a few minutes of downtime if a fuel top-up is needed. Battery powered trucks require regular battery changes and a carefully planned recharging regime. Low battery levels can prevent electric truck operators from using high-powered attachments but a diesel truck is fully operational as long as there is even a small amount of fuel in the tank.

Where the workplace is remote 

Think, for example, of a construction site before the mains electricity supply has been extended to reach it. Keeping an electric truck supplied with recharged batteries is difficult in those circumstances but fuel for a diesel forklift is relatively easy to transport to wherever it is needed.

Where capital is in short supply 

Diesel trucks cost considerably less to buy than electrics, so they will remain a popular choice for any business that needs to minimise capital investment.

Increasingly strict exhaust emission regulations... are driving manufacturers to make engines cleaner and more efficient.

Dealing with emissions

The main argument against diesel relates to emissions. Burning diesel, like any other fossil fuel, produces carbon dioxide and contributes to climate change. Diesel combustion also releases particulates and other pollutants which are damaging to human health. In the UK alone, it is estimated that around 5,000 premature deaths each year are related to exhaust emissions from combustion engines. It should also be remembered that the earth does not have an endless supply of fossil fuel, so we need to conserve it.

Thankfully there is much we can do to make diesel engines emit less pollution and consume less fuel. Increasingly strict exhaust emission regulations, in the EU and the United States in particular, are driving manufacturers to make engines cleaner and more efficient.

Since 1996 the EU has been implementing new limits in a series of stages. These specify the acceptable levels of nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO) and – in the case of diesel engines – particulate matter (PM) from Non-Road Mobile Machinery (NRMM). When we talk about particulate matter we refer mainly to soot particles but PM also includes oil residues. If you really want to know all the details you can look at Directive 97/68/EC and its various later amendments.

Most recently you will have seen references to the EU Stage IIIB emission regulations in forklift product literature, or the equivalent Tier 4 Interim when looking at American products. Provided you deal with responsible suppliers, such as Cat® Lift Trucks and its dealers, you need have no worries over complying with the rules. A schedule for necessary replacement of engines is in place and there is a flexibility scheme allowing for sale of existing stocks with Stage IIIA engines. Any truck bought before the introduction of Stage IIIB, or during the period of the flexibility scheme, can be legally operated without modification.