Electric cars are widely hailed as the answer to pollution on our roads. Once a niche product, over the last few years their production has expanded at breakneck speed.
In America, three years ago only two models of zero-emission vehicles (ZEVs) were available, and only in a few states. Now there are 20 different models for sale across the country.
ZEVs are plug-in electric vehicles that rely on rechargeable batteries to power the car. Part of the reason for the uptick in production is increasingly demanding environmental regulations imposed by governments. But the fact that a car runs on electricity rather than petrol or diesel doesn’t necessarily make it more environmentally friendly.
What determines whether or not an electric car is greener than the alternative?
Firstly, it depends on what kind of car it is replacing. If it eliminates an old, heavy, petrol-guzzling tank then certainly. But if it replaces a modern diesel car of a similar size and weight, then one may be simply trading emissions from the tailpipe for emissions created by the energy used to charge the car.
The green factor also varies depending on where the car is charged. If the area uses clean or renewable energy sources like hydro-electricity, nuclear or wind and solar power, then the car will be cleaner. But if the power is created using coal – still the leading source for power generation in many populous countries – then it will be little better than a regular car.
Lastly, the environmental impact varies based on the time of day that the car is charged. Using a power source during peak hours can result in proportionately lower emissions overall. This is because peak demand requires that every available energy generator, including clean as well as dirty sources, is put to use. The inclusion of clean and renewable sources to the mix reduces the overall amount of carbon dioxide emitted per kilowatt-hour of electricity generated.
Many see zero-emission vehicles as an integral part of improving environmental prospects. China wants 30% of its government vehicles to be ‘new-energy’ in two years, aiming for 5m by 2020. Europe is aiming for 10% by 2025. But unless the creation of the power itself is addressed, how green these vehicles actually are will continue to be a lottery.