Changing energy landscape

Compressed Natural Gas (CNG) is a viable alternative to LPG in powering forklifts. It has been something of a slow burner in terms of uptake in the UK but against the background of increasingly stringent emissions regulations on diesel, the smart fleet manager will consider all other options.

Charles Thurman-Baker is sales manager at Marshall's Industrial, which is a distributor of Volkswagen Powersystems, IMPCO fuel systems (including CNG) and Doosan diesel engines. He thinks there is plenty of life in diesel still but concedes that increased regulation has made diesel more costly both in terms of engine purchase and maintenance.

Charles explains: "Diesel is a fantastic product. It offers a power profile that suits most industrial engines. Therefore, we simply will not see the death of diesel engines in forklift trucks. 

"That said, there are interesting times for diesel engines. To move on to higher stages of tighter emission regulations will be more expensive and it's not just manufacturing, it's the ongoing maintenance costs. Forklift trucks often don't work hard enough to help diesel particulate filters burn off the soot. The start / stop operation doesn't suit this."

The Doosan G2 Tier-4 & Euro-Stage IIIB compliant diesel engine, distributed by Marshall's, works without the need for a DPF (Diesel Particulate Filter).

"Furthermore," says Charles. "With the stage V levels of emission, diesel powered trucks will/should be clean enough to operate indoors, which could mean an increase in the use of diesel."

Rather than prompt the end of diesel, stiffening regulations will shift the changeover points at which fuel choices become viable, says Charles.

"The lower end is nearly all electric, there is a changeover to LPG / CNG and then most of the top end is diesel. I think what will happen over time is that the changeover points will move upwards, so electric will move to higher outputs, then you'll have electric / LPG, then you'll have CNG / diesel.

"With CNG there are lot of larger engines, whereas there are very few large LPG engines, because management of the gas canisters is too difficult. Large CNG engines are in use already on buses and lorries, so there will be products that are inexpensive enough to be converted for use with larger capacity forklifts."

CNG v LPG

While diesel emission challenges provide an interesting background to the development of other power choices, at the moment the main opportunity for gas-powered forklifts is dependent on applications which combine indoor and outdoor work. Here, diesel trucks are seen as too dirty for indoor work, while electric trucks are often seen as not robust enough for yard work (although this perception is changing). LPG may be the predominant option here, but CNG can challenge.

Adam Wise, technical support engineer at Marshall's Industrial says: "CNG is cheaper than propane in terms of running costs. We have case studies where an end user has changed their whole fleet to CNG, and are saving a lot of money over propane."

Marshall's IMPCO CNG solution is Hyster approved. Marshall's supplies a conversion kit and instructions, which requires, for example, software updates to inject more fuel.

Adam continues: "CNG is also easier and safer to produce and store. It is lighter than air so if a leak occurs, it disperses easily. In contrast, propane is more dense than air and will collect into in the event of a leak creating an ignition hazard."

With CNG, there are also no fuel handling safety issues, for example, trucks with LPG bottles on the road and bottles in the plant. They are relatively rare, but there have been instances of fire in areas where LPG cylinders are stored, causing cylinders to explode and shoot off.

Natural gas is also a cleaner burning fuel than LPG, and with mains gas supplied virtually throughout the country the fuel is reliable and 'on tap'.

CNG does require a certain amount of infrastructure to be built, however. For mains gas to be used with forklifts a compressor and filling station must be installed. For low usage applications (one truck used four hours per day or less) a slow fill station that can refill overnight may be sufficient. This costs around £5,000 to install.

Adam continues: "To use the trucks more often you need fast-fill and that costs approximately £100,000 for a fleet of trucks. You need a large capacity CNG pipe come to the facility and storage space. A truck can be refilled in two minutes using fast-fill, with trucks operational for 4-6 hours per refill. Running hours are important to the success of an installation. CNG will prove its worth in big DCs with trucks running 24 hours a day.

"But every site is different and you need to analyse quite closely to determine the best fuel choice. Even within an application, forklift use can vary dramatically. For example, with one customer we've observed, they load and unload on different sides of the yard. The loading forklifts use twice as much fuel as the unloaders."

In addition to this investment, the downsides of CNG revolve around its small footprint in the market. There are no dedicated CNG forklifts at present, with models in use being converted from LPG. There is also no established market for second hand CNG trucks. As well as this, bigger cylinders are required to store CNG as opposed to LPG.

An encouraging sign for CNG is increasing uptake among HGVs. A number of 3PLs have taken the plunge and converted some lorries to CNG. In addition, the Government has committed to maintain the differential between the main rate of fuel duty and the rate for CNG until 2024 because it is a cleaner fuel. The commitment gives businesses long-term certainty when considering CNG investments. The duty on CNG is 24.7p/kg (equivalent to approximately 18.6p/litre of diesel). That contrasts to a duty on diesel of 57.95p/litre.

Charles explains: "If a company has a fleet of HGVs running on CNG then it will have made significant investments in infrastructure and this may make it more affordable to include forklifts as part of an overall package."

The forklift market could piggy back on increased CNG update in lorries, especially if this builds greater awareness of CNG.

While CNG may not be right for every site, it is a viable alternative to LPG, particularly at a time when diesel is under pressure to comply to ever more stringent emissions regulations.