Review of the new Saab 9-5 2.3t Biopower Range

It's tough to make a case for fossil fuels. Future generations will look back with horror and bemusement at the headless rush to deplete a resource that is to all intents and purposes irreplaceable. There are sustainable alternatives available if you're willing to open your minds a little, as Saab are keen to prove with their BioPower Range of models. Instead of being diverted by short-term dead ends like LPG, another fossil fuel, or the long term dream of hydrogen fuel cells, Saab has instead delivered a system that uses sustainable fuel sources right here, right now. What's more, it's no underpowered bore either, the latest 9-5 2.3t BioPower serving up 230bhp of greener grunt.

Running a car like a petrol-electric hybrid is all well and good, but it's worth considering what others will think of you. They'll have you down as some sort of leftie lentilista, smugly looking down your nose at everybody else as you whirr along sanctimoniously. The great thing about this Saab is that you don't need to flaunt your green credentials quite so ostentatiously. To the uninformed, it just looks like another Saab 9-5, long, lean and wearing those unusual Dame Edna-style specs at the front.

Plant your right boot, however, and if you've got a tank full of bioethanol E85, you'll jet to 60mph in 7.6 seconds. Fill it with regular 95 RON, as you can if you want, and you'll add 0.6 seconds to that figure. This performance boost is something Swedes are waking up to before anybody else, native supercar manufacturer Koenigsegg getting the best performance figures from their cars when run on E85, which has an octane rating of 104. In this country, it's still around two pence per litre cheaper than unleaded, so you win every way up. Saab's Trionic engine management system automatically detects whether you have bioethanol or unleaded petrol, or indeed any conceivable mix of the two, and adjusts the car's ignition for optimum efficiency.

"So many environmentally friendly projects are pie in the sky. Saab has come up with one firmly grounded in reality"

The biggest impediment to the take up of this fuel in the UK has been availability. Morrisions started pump deliveries of bioethanol in March 2006 and the chain has been spreading it across many of its converted Safeway stores in the East and South West of England. Saab is bullish about the prospects of BioPower, expecting the take up rate to accelerate as newer and more exciting models come on stream.

Biological fuel sources are nothing new, as many farmers will have realised down the years, running their vehicles on ethanol which can be derived from corn, wheat, potato wastes, sugar beet, forest residue, molasses, sugar cane and virtually any other form of cellulose. Petroleum is also used to make industrial ethanol.

Ethanol, which is the same chemical as the alcohol in alcoholic beverages, can reach 96% purity by volume by distillation, and is as clear as water. Ethanol is flammable and pure ethanol burns more cleanly than many other fuels. However, pure ethanol reacts with or dissolves certain rubber and plastic materials and cannot be used in unmodified engines. Additionally, ethanol has a much higher octane rating (about 115) than ordinary petrol, requiring changes to the compression ratio or spark timing to obtain uncombusted nonvaporized ethanol. If 5 per cent ethanol is mixed with petrol, no engine modification is typically needed, although if you go higher, you'll need a revised fuel system as well as more durable valves and valve seats. This is how Saab has modified the 9-5 BioPower, a car that uses an 85 per cent ethanol, 15 per cent petroleum mix. Therefore the fuel isn't from a totally renewable source, but it represents a good start. Engineers are also looking at the feasibility of gradually upping the percentage of ethaol in the fuel to augment its sustainable credentials.

E85 bioethanol was introduced nationwide in Denmark, and in 1989, Brazil produced 12 billion litres of fuel ethanol from sugar cane, which was used to power 9.2 million cars. With an octane rating of 104, this makes the 9-5 BioPower a good deal swifter than if running on normal 95 octane petrol. Saab estimate a 20 per cent gain in brake horsepower and a 16 per cent boost to torque. The addition of a small amount of petrol helps the engine under cold start conditions. With oil prices at a record high, motorists could make long term savings, get better performance and help the environment by switching to BioPower. Those amongst you who paid attention in chemistry classes will know that the net products of ethanol combustion are carbon dioxide and water. So where's the environmental benefit? Aside from being able to replenish the fuel stocks, the plants harvested to create the ethanol consume more carbon dioxide in their growth cycle than the resultant fuel will emit when burnt, meaning a net depletion of CO2. Now that is clever.

US magazine Popular Science certainly thought so, the 9-5 BioPower featuring in their annual ranking of 100 breakthrough products and technologies that represent a significant leap in their categories. To date Saab has sold over 5,000 9-5 BioPower models in its home market since sales began in July 2005, to take 1.5 per cent of the total Swedish new car market. The Saab 9-5 BioPower is already outselling all other eco-friendly vehicles combined in Sweden, it's unique combination of 20 per cent more power, with fossil CO2 emissions reduced by up to 70 per cent, forming a key part of its appeal.

Pragmatism is a key tool in getting people to switch from fossil fuels. Show them an alternative that's cheaper, offers more power and which requires no effort on the user's part and it has to be a surefire winner. Saab certainly hopes so.