DATA from 26 countries over 15 years has led to two university researchers finding that higher EV uptake generates more CO2 emissions, not less.

The surprising trend is not related to EV use, but to the fact that many countries are still using electricity generated by burning fossil fuels like coal or oil. The research said that EVs are only as green as the power they plug into.

Researchers from the University of Auckland and Xiamen University in China, published in the journal Energy, analysed the environmental impacts of human activity and used a robust statistical approach to investigate what drives a nation’s CO2 emissions.

Associate Professor Stephen Poletti and Simon Tao, a doctoral candidate at the Business School’s Energy Centre, didn’t observe a significant reduction in CO2 emissions globally due to EV adoption.

Stephen Poletti

“On the contrary, EV adoption is positively associated with CO2 emissions,” said Professor Tao.

“This finding appears counterintuitive; it challenges the conventional belief that EVs contribute to decarbonisation.

“Our analysis highlights that the environmental benefits of EVs are contingent on the composition of a country’s electricity generation mix.”

Professor Poletti said EVs charged by using electricity from coal-fired power plants “may indirectly contribute to higher emissions than modern gasoline or diesel vehicles, especially considering the entire lifecycle from production to disposal.”

The study results suggest that only when the global share of renewable electricity generation reaches approximately 48 per cent will electric vehicle adoption contribute to reducing CO2 emissions.

Simon Tao

Professor Poletti said that renewable energy – mainly wind, solar and hydro – accounted for only a little more than 30 per cent of the world’s electricity in 2023 “so there’s a way to go.”

“Electric vehicles are often seen as a silver bullet for climate change, but our results show that’s not the case if the electricity powering them isn’t clean,” he said.

New Zealand, where more than 80 per cent of electricity generation is renewable, is well-placed to reap the benefits of EVs. 

In Australia, a Clean Energy Council report found that renewables overall accounted for nearly 40 per cent of Australia’s total electricity supply in 2023.

“This research is a reminder that decarbonising transport can’t happen in isolation,” Professor Poletti said.“EVs are only as green as the grid they plug into, and government policies should aim to increase the adoption and integration of renewable energy like solar and hydro. “This can be achieved by setting ambitious renewable energy targets and providing adequate subsidies such as tax credits to producers and consumers of renewable energy.”

He said that investments in smart grids and transmission networks can boost the efficiency and reliability of renewable energy supply.

“Policies should support community-based renewable energy projects, which can increase public acceptance of renewable energy installations,” he said.

Further, the researchers say eliminating subsidies for fossil fuels and implementing carbon pricing mechanisms could also incentivise renewable energy development.

“Electric vehicle uptake can help countries meet climate-related targets, as long as the energy used to power them is clean,” said Professor Tao.

In addition to EV uptake, the researchers examined the impacts of economic growth, green technology innovation, renewable energy consumption and population density on emissions.

They found that economic growth increases emissions, while innovation in environmentally friendly technology and population density, in the form of more compact cities, can help lower them. 

Renewable energy use had the most significant emissions-reducing effect.