But are viable alternatives available now and how can fleet operators minimise these fuel-related risks? Over the following pages, we try to shed some light on the options currently available, using both existing and new, cutting-edge technologies.

Liquid Petroleum Gas

Liquid Petroleum Gas, or LPG, has made several attempts to make inroads into the UK fleet market. LPG numbers peaked in 2003 but declined dramatically in 2004 following the removal of a Government grant scheme. This resulted in most vehicle manufacturers stopping production of LPG models.

The key benefit of LPG is reduced fuel costs (average UK pump price for October 2009 is 54 pence per litre) although there is a price premium for an LPG car, with the average cost to convert an engine typically falling between £1,000 and £1,800. The cost savings from the cheap fuel should provide an overall cost saving over petrol in the short to mid-term, dependent on mileage. Other benefits include reduced CO2 and exhaust emissions.

Downsides of running LPG vehicles include; a limited refuelling infrastructure, limited availability of LPG model vehicles or engine converters, and some reliability issues.

The largest cost savings are available for depot-based fleets (on-site bunkering of fuel is even more cost-effective). LPG may be making a comeback due to high petrol and diesel prices, but will probably remain very much a niche fuel.

Hybrid

Hybrid cars utilise two power sources, typically petrol and electricity.

They use traditional high efficiency internal combustion engines but have an electric motor to provide extra power when needed.

Regenerative braking means that the cars don't need to be charged or plugged in to an external electrical supply as they recharge the batteries when braking. Hybrids are most effective in urban stop-start driving environments and can drive in electric mode only at low speeds.

Plug-in hybrids are now coming to market that have larger battery packs and although they require plugging in, their range in electric mode is considerably greater.

Plug-in hybrids have a significant price premium, however Government grants are being introduced in 2011 which could offset this.

Due to their fuel efficiency, hybrids have some of the lowest CO2 emissions of any car available in the UK. Significant cost savings are generated for employers through lower Vehicle Excise Duty, Class 1A National Insurance contributions, 100% writing down allowance and lower fuel costs. The employee can also benefit from lower company car tax and lower personal fuel costs.

Hybrids are becoming very cost-effective now as their numbers increase, and in the short to medium term look to be a very cost-effective solution.

You can expect to see greater model availability in the next few years, astheir only real drawback is limited model availability. The current low emission hybrids available in the UK are the Honda Insight, Civic IMA and Toyota Prius.

Bio fuels

Bio fuels can be viewed as a sustainable fuel source, which could help move the world's reliance away from fossil fuels.

The CO2 benefit of bio fuels is that the plant or crops that yield the bio fuel absorb CO2 while they are growing, which offsets much of the CO2> that is later emitted from the vehicle's exhaust.

The key issue with bio fuels is where the raw material is sourced. Bio fuels can come from many sources including recycled cooking oil, plant matter and crops. Bio diesel or bio ethanol is available through UK forecourts as low blend mixes with standard petrol and diesel. Using high bio-blends requires vehicle modification or a suitable vehicle to be obtained in the first place.

Bio fuels provide environmental and sustainability benefits, however their cost of production usually offsets the duty rate discounts provided by HMRC. This option therefore targets longer term sustainability and rarely provides cost saving opportunities for fleet operators, even though there is typically no cost premium for the vehicle.

Compressed Natural Gas

Compressed Natural Gas, or CNG, is mainly used on commercial vehicles (usually HGVs) as the fuel tanks are typically heavy, large and expensive.

Limited light weight vehicles exist in the UK with the only manufacturer offering being Volkswagen's Caddy van. CNG has always had similar problems to LPG but on a larger scale. Essentially, users need to provide their own refuelling facility, making this option only really available for large "return to depot" fleets.

CNG is therefore not expected to make any significant inroads into the UK car market in the short to medium term.

Electric cars

Electric cars have been promoted as potentially being the environmentally friendly vehicle of the future as they produce no exhaust emissions, and recent improvements in battery and motor technology have made them more practical.

The UK is currently seeing an increase in interest in electric light commercial vehicles, but actual sales of electric cars declined in 2008.

Typically, electric cars cost more than traditionally-fuelled cars to operate, due to the high cost of the batteries. This is despite the fact that they benefit from cheap fuel, zero rate VED and other tax breaks. In London, however, a 100% discount from the London Congestion Charge, free parking and plug-in points (in some boroughs) can make them cost-effective, and explains why most of the UK's electric cars are operated there.

Electric vehicles are seen by many as the mid to long term environmental solution, although vehicle cost and range limitations mean these vehicles are only suitable for urban driving conditions, so again are very much niche players.

Government grants to promote electric vehicles are being introduced in 2011, which may help address the cost issues.

Hydrogen fuel cells

For many years, hydrogen fuel cells have been a future dream, but now some vehicle manufacturers are getting tantalisingly close to a practical working solution.

Currently the cost of the vehicles is prohibitively expensive and there are still issues over range and reliability. The biggest issues to overcome, however, will be the provision of a suitable refuelling infrastructure, and the clean and efficient production of sufficient volumes of hydrogen.

In short, we believe it will be a minimum of 10 to 20 years before we can expect to see hydrogen powered vehicles on our streets in any significant numbers, although Honda has already released the 'Clarity' hydrogen fuel cell car in Japan and the US.