Power shift
August 1st 2006

Significant progress has been made in the design of 'clean' engines and the control of forklift truck exhaust emissions, but with no let up in the amount of new environmental legislation emerging from Europe, truck users are seeking more eco-friendly fuels

With greenhouse gases and exhaust emissions growing causes of concern and health and safety legislation demanding the highest levels of welfare within the workplace, a forklift truck's 'green' credentials are a major consideration for today's truck specifier. And while, in recent years, there has been significant progress in both the design of 'clean' IC-engine powered trucks and the control of exhaust emissions, more and more companies are seeking more environmentally-friendly fuel sources for their forklift fleets.

Natural gas is regarded by many as the cleanest burning fossil fuel and over the last decade or so sales of lift trucks powered by Compressed Natural Gas (CNG) have been enjoying steady growth. According to Benchmark Research's highly regarded survey of the lift truck market, some 11% of all counterbalanced trucks sold in the UK during 2005 were CNG-powered and this figure is expected to continue to rise.

Because it contains significantly fewer harmful pollutants than other fuels, CNG exceeds all current and anticipated indoor and outdoor air quality standards. It offers significantly reduced air pollution since it produces little smoke, odour or carbon dioxide emissions and, in addition, carbon monoxide emissions and other exhaust hydrocarbons are reduced. Furthermore, CNG is virtually free from lead, sulphur particles and aromatic hydrocarbons that cause general air pollution. In simple terms, all of this means exhaust emissions from CNG-powered trucks are so low that the trucks can be operated both outside and inside a building without putting staff at risk or creating an unpleasant working environment.

Improved performance

In addition to offering improved workplace air quality, CNG-powered forklifts' performance characteristics and running costs also compare favourably with liquified petroleum gas (LPG) and battery-powered alternatives. During typical applications, for example, a full tank of CNG will support a complete eight-hour working shift.

Furthermore, noise and vibration fatigue levels among operators are proven to be reduced, while truck downtime is less and service intervals longer when CNG is used.

Historically, despite the host of benefits offered by CNG, the practicalities of having a storage tank on site have limited the uptake of the fuel particularly among companies operating smaller fleets. Potential users have been put off by the cost of installing refuelling equipment and also by the widely held belief that the refuelling process is somewhat less than straightforward.

In truth the process for 'topping-up' a CNG-powered truck is relatively simple and, while set up costs must be considered, the long term pay-back from CNG means that truck operators can achieve sizable cost savings over the lifetime of their fleet even allowing for the installation costs of storage and compressor facilities.

There are two main ways of refuelling compressed natural gas equipment the 'fast fill' and 'slow fill' methods. The 'fast fill' system allows CNG refuelling in approximately two to three minutes and is usually adopted when fleets of six or more units operate on a multi-shift basis. The 'slow fill' method is more suitable for single shift applications where less than six units are on site. It uses what is known as a 'Fuel Maker' and refuels a system in around eight hours.

Safe refuelling

The actual refuelling operation is extremely safe. It is a sealed process so there are no hazardous spills and the operator does not need to wear special protective clothing.

Also, because the fuel is delivered underground via the national gas supply network, the need for hazardous fuel tanker deliveries is removed.

"Safety is a vitally important factor in the workplace and neither personnel nor product safety can be compromised by the presence of lift trucks," says Tom Pickering, Yale Europe Materials Handling's product sales manager. "Since CNG is lighter than air and has a narrower flammability range than LP Gas and diesel, accidental ignition is almost impossible. Yale's range of CNG trucks have an excellent safety record. They incorporate special vents which release gas into the atmosphere in the event of excessive pressure caused by exposure to fire or heat. If this gas should then ignite it will burn with a controlled flame."

Yale has been at the forefront of CNGpowered truck developments and first introduced the concept to the UK market in the mid 1990s. By this time CNG trucks were already popular in the United States. The company now has several hundred CNG counterbalanced trucks operating throughout Europe.

One of the earliest converts to CNGpowered trucks in the UK was Bulmers the Cider maker. Based in Hereford, the company first took delivery of a fleet of 2.5t CNG-powered Yale counterbalanced trucks some five years ago.

Bulmers work the trucks hard at the mill and, typically, trucks operating in this kind of environment would be expected to be reaching their working life after five years.

However, because CNG is kinder to engines than other fuels, the trucks' service life has been extended by some 18 months. This has had significant cost saving implications for Bulmers.

A further plus is the fact that, following some restructuring of its production process, Bulmers has been able to streamline its fleet profile from 24 to 18 trucks. The company is now moving the same number of SKUs in and out of the site every day with fewer trucks.

Of course, every individual truck application is different and before any decision is taken to make the switch to CNG, certain practical criteria have to be considered such as, for example, the availability of natural gas at the facility.

Accurate assessment

"Potential users of CNG need to take into account the number of truck units they operate and the amount of time the trucks are utilised. Their truck supplier should be able to give a fairly accurate assessment of the likely cost of running the fleet on CNG," says Pickering.

Worldwide, there are more than a million vehicles operating on CNG and despite the fact that public refuelling stations remain scarce (although more are being introduced at motorway service stations), many haulage operators are being tempted by massively reduced running costs and significant tax incentives to switch a proportion of their lorry and van fleets to CNG. With their own depot-based refuelling facilities on-site these companies are turning to CNG for their forklift fleets in growing numbers.

"By using compressed natural gas forklifts a company demonstrates its commitment to innovation, the environment and employee health and safety," concludes Pickering.

"With no let up in the amount of new environmental legislation emerging from Europe, more and more companies will turn to CNG as an alternative fuel source for their lift truck fleet."

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