In 2008 Top Gear, the world’s most popular TV motoring programme, tested – on the same track and at the same speed – a BMW M3, a high-performance sport sedan with a thirsty four-litre V8 engine, against an eco-friendly Toyota Prius with a 1,5-litre petrol-electric engine.
The aim was to prove so-called green cars such as the Prius aren’t as light on fuel as people might believe. And
indeed, the test by Jeremy Clarkson and his fellow madcap motoring clowns showed the BMW used less fuel than the Toyota.
To celebrate the unthinkable petrolheads worldwide broke out the bubbly and trumpeted the shock result all over the
internet.
But the green camp was unmoved. The only thing the ridiculous test proved, they argued, was the way you drive can have a significant effect on petrol consumption. They insisted if you want to save the environment and money the Prius is still the appropriate car to drive.
But is it? Apart from Lexus’ GS sedan and RX sport utility vehicle (which is geared to performance rather than environmental friendliness) the Toyota Prius is the only hybrid car sold in South Africa. Hybrids are powered by a combination of two powerplants (a petrol engine and a battery-driven electric motor in the case of the Prius).
At low speed the electric motor powers the car and when you brake the battery is charged by the car’s kinetic energy. This saves fuel and results in less environment-damaging exhaust emission.
But a car’s true green characteristics don’t begin and end with the exhaust pipe. You have to take into account the materials used to build it – materials that had to be mined, transport of the materials and what can be recycled when the car reaches the end of its life.
This is where the Prius loses many of its green points. The mining of the nickel used in the battery has a devastating environmental impact, causing soil erosion, air pollution and acid rain. The area around the mines can look like a bleak
lunar landscape.
Other materials used come from all over the world and the vehicles used to transport them use fossil fuels such as oil. Yet the Prius is supposed to reduce emissions caused by the burning of these fossil fuels.
Batteries are heavy and the Prius weighs about 10 per cent more than its petrol-driven equivalents. Its electric engine contributes to fuel saving but the battery’s weight largely negates the advantages because the petrol engine must work harder to move the extra weight. A smaller, lighter engine can be just as light on petrol.
So the Prius seems not to be the greenest car around.
Read the full article in the YOU of 18 February 2010.