Alternative Fuel and Transportation

Published on April 27th, 2009 | by Derek Markham

Just How Green is That Electric Car, Anyway?

With the push to reduce the carbon emissions from transportation, sometimes the newest developments, the latest technology, gets the spotlight. By putting more hybrid and electric vehicles on the road, though, are we really getting “greener” vehicles? A report by an independent UK transportation group, Transport Watch, may have some surprising information for electric car aficionados.

Photo: frankhElectric Car

Electric Car

If your electric vehicle is charged with electricity from a coal-fired power plant, then the CO2 emissions to fuel your EV are about double the amount emitted by a diesel engine, due to the inefficiencies in electrical power generation and transmission.

According to Transport Watch, only about 30% of the energy generated by the power plant actually reaches the vehicle because of losses in the transmission route. Of the energy delivered to the vehicle, 20% is then lost to the batteries and electric motor. This means that most EVs are only about 24% efficient.

Contrast that with a modern diesel engine, which achieves an efficiency of 40-45% on the fuel burned by the vehicle. Granted, the internal combustion diesel engine does emit CO2 at the tailpipe, while an EV does not. However, the CO2 emitted by the EV is not seen at the curb, leading to the assumption that electric cars decrease CO2 emissions overall.

“We conclude that the notion that electric cars will reduce emissions is a fiction unless we hypothecate that the UK electricity generating industry will be de-carbonised.” – Transport Watch

If a true low-carbon transportation initiative catches on, we might be seeing more diesels and less electric vehicles on the road, simply because of efficiency. Coupled with the fact that manufacturing new EVs takes new technology, materials, and factory re-tooling, the CO2 emissions factor could mean that diesels are the cleanest transportation option we have right now.

If large-scale renewable energy electric power plants start feeding the grid, and EV owners can opt to choose clean energy for their cars, then a shift to an electric vehicle economy will begin to make the most ‘green’ sense. Until then, however, EVs are still coal-powered vehicles…


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