A comedian on the TV was recently rubbishing the green credentials of hybrid cars. He did seem to have a point with his doubting as he found that on comparable journeys the fuel consumption of the hybrid car was similar to that of an equivalent diesel powered car. He also made out that the hybrid car contained two engines, both of which were being worn down by the journeys and that meant carriage of extra weight.
Curious then that the hybrid bus when used in Birmingham, really does use less fuel than the conventional bus. I thought I needed to know more.
Diamond Bus were keen to show me an example of their hybrid fleet, Straight away one myth was blown away; the bus does not have two engines but one. The wheels on the bus are operated by an electric motor. The electric motor is powered by a battery, and the battery is charged by a diesel engine. This really is quite sensible as an electric motor does not need various gears and, when moving slowly or at a standstill, little or no energy is needed.
It is because when at bus stops, traffic lights or generally standing, energy is not being burned, that the hybrid bus has less of a thirst than the standard diesel.
Burning diesel is not green and the hybrid’s claims can be overstated. The form of the bus is a move in the right direction and battery powered electric could be increasingly powered by solar on the bus body and recharging points at bus garages. Reduced exhaust from diesel means better air quality and improved human health and this, surely justifies the bigger price tag. Longer term, a bus based around an electric motor may last longer than a diesel bus grinding through the gears; in whole life costs the hybrid bus could be a winner.
The reassuring symbol of manufacturing quality, Mercedes Benz, speaks of a West Midlands lost opportunity. Not only should all buses be at least ‘hybrid’, but also ‘Made in Birmingham’.
