Fuel for thought

They’ve been running cars on ethanol for years without incident in South America. But apart from adding a small quantity of the stuff to our unleaded petrol it really hasn’t taken off here yet.

And even this small quantity has not been without controversy, with claims that it can damage engines.

That could all change, however, with the arrival of Saab’s BioPower cars, designed to run specifically on ethanol – led by the Saab 9-5 BioPower.

We’re not talking about 10 per cent, but E85 or 85 per cent pure ethanol, which is combined with 15 per cent unleaded petrol.

While some engineering changes are required to run E85, Saab says it does not require any special technology. BioPower vehicles will run happily on either petrol or ethanol, but some modifications are required before you go sticking ethanol in the tank because of its corrosive nature.

They include the addition of more durable valves and valve seats and the use of ethanol compatible materials in the fuel system, including the tank, pump, lines and connectors. In return you get a more environmentally-friendly fuel and one that delivers better performance, because of its higher octane rating. The trade-off is that you burn more of it.

Ethanol is alcohol distilled from grain, cellulose or sugar cane. It has been produced from sugar cane for many years in Brazil and also from corn in the the US Mid-West.

In Sweden, it is produced from wood pulp and forest residues, with feasibility studies to see whether it can be produced from lignocelluloses.

As a fuel, the most important difference between petrol and ethanol is that ethanol does not add to global carbon dioxide (CO2) levels.

This is because CO2 is removed from the atmosphere during photosynthesis by the crops grown to produce ethanol.

The main thing, of course, that ethanol is renewable and oil isn’t.Currently Saab offers BioPower versions of its 2.0 and 2.3-litre turbocharged four cylinder engines.

Our test vehicle was a 2.0-litre wagon with “Saab BioPower” emblazoned on the side. Normally this engine would produce 110kW of power and 240Nm of torque, but with E85’s higher octane rating of 104RON this figure is boosted to to 132kW and 280Nm.

The wagon certainly has plenty of zip, but at the same time seemed to chew through a full tank of E85 quickly.

We had barely travelled 170km before the 68-litre (not standard 75-litre) tank was reading half empty and at 319km the low fuel light came on.

By 347km the trip computer was demanding we refill the car. If you are planning any long distance trips this could be an issue, as there only half a dozen fuel outlets in NSW that offer E85. At the time we refilled the tank, the trip computer was proclaiming fuel consumption of 13.9 litres/100km.

However, the tank only took 58.4 litres of E85, which working out the maths put our consumption at 16.8 litres/100km – about the same as a hoary old V8.

There are no official fuel consumption figures for the 9-5 BioPower, but in comparison the same car with a 2.0-litre petrol engine delivers a claimed 10.6 litres/100km.

Of course this needs to be weighed up against the cost of E85 (85.9 cents a litre when we filled up), compared to unleaded which was selling at the same servo for 116.9 cents – 26.5 per cent less. However, as we were burning 58 per cent more fuel, that in fact puts us 31.5 per cent behind the eight ball.

Saab meanwhile claims fuel consumption for the BioPower is about the same as a petrol model at constant cruising speeds. But in mixed driving conditions it is uses about 25-30 per cent more E85. Carbon emissions for the petrol engine are 251 grams, but there are no figures on ethanol.