BusinessCar assesses the leading fuel technologies and reveal which is the best green option for UK companies

Once upon a time there used to be just petrol and diesel engines. Today and increasingly tomorrow, organisations will be able to choose up to a dozen ways to power their fleets, but which way should you go?

Direct-injection petrol, common-rail diesel, full electric, hybrid electric, bioethanol, gas-to-liquid, fuel cell, hydrogen, LPG, CNG. it’s all very confusing.

Most fleets just want their vehicles to move around as safely and efficiently as possible, avoid too much tax at the pumps and company car tax for the drivers, plus have a technology under the bonnet that will be worth something in residual value terms after three or four years. But increasingly, they also want to look and act in a responsibly environmental and sustainable way too. It’s a tough remit.

So we trawled through all the various existing commercially available fuel technologies, plus speculated a little on future ones you may have heard about – and rated the top 10. We judged on emissions (that’s all of them, and not just tailpipe CO2), fuel economy, tax benefits, availability and long-term viability – and then crowned a winner. So, counting down from the number 10 spot.

10. GTL (Gas to Liquid)

Eco fuel rating 44%

What is it? A type of diesel made from natural gas rather than oil. Can be used as a blend with normal diesel or neat.

For Allows use of remote gas resources created in oil refining process by turning them into a liquid that’s transportable, thus avoiding waste or needless CO2 creation from ‘burn-off’ – the flames commonly seen on oil rigs; Little or no engine mods needed to run GTL blends with diesel fuel; Can offer higher cetane rating (more power and efficiency) than normal diesel; overall greenhouse gases (well-to-wheel) said to be lower than normal diesel – especially in use.

Against No plans to sell fuel in UK yet (maybe by 2010 as a diesel blend); High production costs at present compared to normal diesel; Some existing engine tech is not yet sharp enough to fully exploit its benefits; Non-renewable.

Who are the market leaders? Audi uses neat GTL in its R10 TDi Le Mans diesel racecar with Shell as fuel provider. South African/USA fuel maker alliance Sasol Chevron is another player developing the fuel.

9. LPG

Eco fuel rating 52%

What is it? Conventional petrol engines are converted to run on liquefied petroleum gas or petrol – thus becoming ‘dual-fuel’ vehicles. LPG is a byproduct of the oil and gas industries (and is the generic name for commercial propane and butane).

For Lower emissions (especially local air problem emissions); Reduced fuel duty about half the price of petrol and diesel, as well as other tax breaks.

Against Despite almost 10 years in the UK as an established player at manufacturer level, there is still not a critical mass of conventional filling points for the vehicles; Less efficient than petrol and diesel; Requires a separate tank and filler cap; Fuel duty benefits are slowly reducing; Factory-fit carmaker support for the tech is seriously on the wane.

Who are the market leaders? Vauxhall.


Eco fuel rating 56%

What is it? Compressed natural gas is a gaseous fossil fuel consisting primarily of methane (basically cooker gas) that can run in converted combustion engines either by itself or as a dual-fuel vehicle alongside petrol or diesel.

For One of the cleanest technologies currently available from a total emissions tailpipe perspective; Some tax breaks for fuel and vehicle use.

Against Hidebound by thick, heavy and large separate fuel tanks that work better in LCVs and buses; Almost non-existent refueling infrastructure outside of private depots or limited industrial spaces; Non-renewable.

Who are the market leaders? Volvo (cars) and Mercedes (LCVs).