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FOR THOUGHT
The future of diesel as a practicable engine fuel could be in doubt. Chris Graham considers some of the alternatives.
The arguments for and against alternative fuels drag on with, it seems, little progress being made. Every now and again there's a spurt of enthusiasm from one quarter or another, then interest disappears for a bit. But the days for dallying are melting away.
Alternative fuels are set to become a raging issue within the commercial vehicle sector over the next few years. With fuel industry giants such as Mobil making big efforts to finalise its product strategies, and high-profile fleets such as Safeway engaged in alternative fuel vehicle trials, the stage is set for an interesting battle.
Environmental issues As is so often the case, legislation and regulation will be the driving forces behind change. The recent international conference in Kyoto focused attention on environmental issues—specifically the steadily rising levels of carbon dioxide production (23% of which is emitted by motor vehicles). But while CO2 is certainly a cause for concern with regard to atmospheric warming, there are other pollutants which are potentially more serious.
The monitoring of these other nasties, which include nitrogen oxides (NOx) and the dreaded
particulates, is at the core of the UK Government's National Air Quality Strategy (NAQS). It's been estimated that NOx has 40 times more global warming potential than carbon dioxide, and that I IC Vs are responsible for nearly 60% of NOx emissions from road traffic.
"So what?" says Joe Soap haulier. 'There's not a lot [can do to improve things on a global scale. My fleet is well maintained and dieselpowered. That's the way it's always been!" Well, unfortunately the net is tightening. Whether you accept the emission-induced climate change theories or not, the reality is that the authorities do and they are the ones with the power to act. Restrictions will be enforced progressively and those who continue to pollute will be made to pay for their actions. Now is the time to start planning You must consider your operation and look to the future.
Colin Matthews is sales and marketing manager at Mobil CNG, and he has clear views on the best way forward. "The core of our thinking is that operators must decide on the right fuel for the right vehicle, dependent upon application," he explains.
It seems likely that conventional diesel will remain, but its inherent polluting problems will eventually limit its use. Also, the Government is committed to annual price increases on the rate of duty of at least 6% above inflation. Matthews believes that diesel is set to become the most expensive of the hydrocarbon fuel options.
Ultra-low-sulphur diesel (ULSD) represents an option for which significant claims have been made. But it costs more to produce, is not widely available and boasts a lower energy content than traditional fuel. The production process is costly environmentally too: 20 tonnes of CO2 is generated for every tonne of sulphur removed from diesel fuel to make ULSD.
When used in combination with a particulate trap LTISD does show impressive reductions in the emissions of hydrocarbons, carbon monoxide and particulate matter; but the problem of NOx production remains.
The arrival of Euro-3 emissions legislation next year will screw down the permitted NOx, CO HC and particulates levels further, followed by yet another reduction when Euro-4 comes into force in 2005. Matthews believes conventional diesel engines will find it hard to achieve these higher levels of efficiency without significant design and operating improvements. He says: "As far as I'm aware there is nothing coming through which is going to help with reducing NOx and, as for the important issue of noise levels, the situation looks rather bleak for these engines."
The tighter Euro standards will apply only to new vehicles sold after implementation, but don't imagine that just because you run a fleet of nearly-new trucks your operation will be unaffected. Matthews warns operators: "The introduction of glow emission zones' could provide an effective block for those running older vehicles. A number of local authorities are already considering this option they will be obliged to implement the NAOS standards.
"Pilot schemes are currently under way, with vehicles entering built-up areas being monitored to record emission levels," he adds, "Quite how such a scheme would be implemented remains open to debate. The one certainty is that legislation will be tightened and the polluters will suffer."
Matthews believes the only financially and environmentally viable solution is to switch to gas power. Currently there are two options; liquefied petroleum gas {LPG) or compressed natural gas (CNG). His money's on CNG because of its advantages over LPG in terms of performance, availability and cost: '''Quite apart from the significant emission benefits CNG has over diesel fuel, it is already cheaper than diesel and will become more so as diesel prices are increased in line with Government plans. We believe the saving when using a product such as our Cleanerburn Natural Gas can be about 15-20p per litre compared with diesel."
Comparisons between a Euro-2 diesel-powered vehicle and one fuelled by Mobil's CNG show that latter reduces HC emissions by 80%, CO emissions by 97%, NOx emissions by 86% and particulate matter emissions by an impressive 94%. That's good enough to meet the yet-to-bc-introduced Euro-3 standard.
Operating noise
The other significant advantage is a reduction in operating noise. It's been established that CNG-powered engines make less noise, at all engine speeds, than conventional diesel equivalents. According to Mobil, independent testing has shown them to be up to 80% quieter, which is a significant factor in view of the growing usage limitations being imposed by local authorities in a bid to counter noise pollution.
Matthews adds: "Safeway, for example, has been able to push back noise-related curfews because of the significantly quieter running of its CNG-powered engines The reduction is accounted for by the fact that these modified engines work more like petrol motors than diesels—it's a spark ignition-based system.
"This allows for night deliveries which reduces congestion during daylight and cuts exhaust emissions," says Matthews. "Safeway has calculated it could perhaps reduce its fleet by 20% if 24-hour operation became possible."
Another query hangs over product availability. While the delivery infrastructure is already in place—existing gas pipelines are perfectly adequate—refuelling stations are few and far 'between. Mobil's preferred solution is to install pumps in operators' yards Engine maintenance requirements are no greater than for diesel trucks, although familiarisation training for technicians will be required. You may also have doubts about the safety of CNG but, according to Matthews, these are unfounded.
"Safety is an obvious concern for those unfamiliar with gas power," he says, "people automatically associate pressurised gas containers with the risk of explosion, but this product really is extremely stable. It's difficult to ignite, requiring a very high intensity spark. If there is a leak then, being lighter than air, CNG disperses instantly—unlike petrol or diesel fumes which can hang in a vapour cloud, with potentially disastrous consequences."
As with anything new, gas power continues to be regarded by many as a quirky, slightly half-baked idea. Current support from the vehicle manufacturers is patchy at best_ But this will change. Gas works as a fuel source. It's affordable, practical and environmentally friendly. What other viable option is there?
E See CM 21-27 January for a report on Iveco's CNG findings.