According to a study by the Norwegian University of Science and Technology, electric cars might pollute much more than petrol or diesel-powered cars.
Researchers found greenhouse gas emissions rose dramatically if coal was used to produce the electricity. Electric car factories also emitted more toxic waste than conventional car factories, claims their report in the Journal of Industrial Energy.
However, in some cases electric cars still made sense, the researchers said.
The team looked at the life-cycle impact of conventional and electric vehicles, considering how the production, the use and the end-of-life dismantling of a car affects the environment. "The production phase of electric vehicles proved substantially more environmentally intensive," the report said, comparing it to how petrol and diesel cars are made. “The global warming potential from electric vehicle production is about twice that of conventional vehicles."
Added to this, producing batteries and electric motors requires a lot of toxic minerals such as nickel, copper and aluminium, meaning the acidification impact is much greater than that of conventional car production.
"Across the other impacts considered in the analysis including potential for effects related to acid rain, airborne particulate matter, smog, human toxicity, ecosystem toxicity and depletion of fossil fuel and mineral resources, electric vehicles consistently perform worse or on par with modern internal combustion engine vehicles, despite virtually zero direct emissions during operation," according to co-author Prof Anders Hammer Stromman.
With electric car production being so damaging to the environment, these cars have already polluted a great deal by the time they hit the road, the report says.
However, if the cars were then powered by electricity made from low-carbon electricity sources, they could nevertheless offer "the potential for substantial reductions in greenhouse gas emissions and exposure to tailpipe emissions" over time. The report counters this by saying that in regions where fossil fuels are the main sources of power, electric cars offer no benefits and may even cause more harm. "It is counterproductive to promote electric vehicles in regions where electricity is primarily produced from lignite, coal or even heavy oil combustion."
According to the study, electric cars do offer environmental benefits when compared with cars with internal combustion engines in Europe, where electricity is produced in a number of different ways. "Electric vehicles powered by the present European electricity mix offer a 10 per cent to 24 per cent decrease in their global warming potential relative to conventional diesel or petrol vehicles."
The report points out that the longer an electric car in Europe stays mobile, the greater its lead over petrol and diesel engines. "Assuming a vehicle lifetime of 200,000km exaggerates the global warming benefits of electric vehicles to 27-29 per cent relative to petrol and 17-20 per cent relative to diesel," it said.
"An assumption of 100,000km decreases the benefit of electric vehicles to 9-14 per cent with respect to petrol vehicles and results in impacts indistinguishable from those of a diesel vehicle."
Battery life has a bearing on an electric car's longevity, not least since batteries are very expensive to replace, although they are gradually improving, which could result in electric cars being used for longer. However, as petrol and diesel engines are also improving, the relationships between the different types of vehicles are not constant.
"A more significant reduction in global warming could potentially be achieved by increasing fuel efficiency or shifting from petrol to diesel," the report said.
"If you are considering purchasing an electric vehicle for its environmental benefits, first check your electricity source and second look closely at the warranty on the batteries," said Professor Stromman.
Researchers found greenhouse gas emissions rose dramatically if coal was used to produce the electricity. Electric car factories also emitted more toxic waste than conventional car factories, claims their report in the Journal of Industrial Energy.
However, in some cases electric cars still made sense, the researchers said.
The team looked at the life-cycle impact of conventional and electric vehicles, considering how the production, the use and the end-of-life dismantling of a car affects the environment. "The production phase of electric vehicles proved substantially more environmentally intensive," the report said, comparing it to how petrol and diesel cars are made. “The global warming potential from electric vehicle production is about twice that of conventional vehicles."
Added to this, producing batteries and electric motors requires a lot of toxic minerals such as nickel, copper and aluminium, meaning the acidification impact is much greater than that of conventional car production.
"Across the other impacts considered in the analysis including potential for effects related to acid rain, airborne particulate matter, smog, human toxicity, ecosystem toxicity and depletion of fossil fuel and mineral resources, electric vehicles consistently perform worse or on par with modern internal combustion engine vehicles, despite virtually zero direct emissions during operation," according to co-author Prof Anders Hammer Stromman.
With electric car production being so damaging to the environment, these cars have already polluted a great deal by the time they hit the road, the report says.
However, if the cars were then powered by electricity made from low-carbon electricity sources, they could nevertheless offer "the potential for substantial reductions in greenhouse gas emissions and exposure to tailpipe emissions" over time. The report counters this by saying that in regions where fossil fuels are the main sources of power, electric cars offer no benefits and may even cause more harm. "It is counterproductive to promote electric vehicles in regions where electricity is primarily produced from lignite, coal or even heavy oil combustion."
According to the study, electric cars do offer environmental benefits when compared with cars with internal combustion engines in Europe, where electricity is produced in a number of different ways. "Electric vehicles powered by the present European electricity mix offer a 10 per cent to 24 per cent decrease in their global warming potential relative to conventional diesel or petrol vehicles."
The report points out that the longer an electric car in Europe stays mobile, the greater its lead over petrol and diesel engines. "Assuming a vehicle lifetime of 200,000km exaggerates the global warming benefits of electric vehicles to 27-29 per cent relative to petrol and 17-20 per cent relative to diesel," it said.
"An assumption of 100,000km decreases the benefit of electric vehicles to 9-14 per cent with respect to petrol vehicles and results in impacts indistinguishable from those of a diesel vehicle."
Battery life has a bearing on an electric car's longevity, not least since batteries are very expensive to replace, although they are gradually improving, which could result in electric cars being used for longer. However, as petrol and diesel engines are also improving, the relationships between the different types of vehicles are not constant.
"A more significant reduction in global warming could potentially be achieved by increasing fuel efficiency or shifting from petrol to diesel," the report said.
"If you are considering purchasing an electric vehicle for its environmental benefits, first check your electricity source and second look closely at the warranty on the batteries," said Professor Stromman.
