Reviewed by Lexie CornerApr 11 2025
According to a study published in Energy by researchers from the University of Auckland and Xiamen University, the environmental benefits of purchasing an electric vehicle (EV) may be limited if it is charged using electricity generated from fossil fuels. The study suggests that, in some cases, EVs may result in higher carbon dioxide (CO₂) emissions than traditional vehicles.
The researchers used a robust statistical method to analyze the environmental impact of human activities and assess the factors driving CO₂ emissions in different countries.
They examined data from 26 countries over 15 years, finding a significant trend: countries with higher EV adoption also experienced an increase in CO₂ emissions. This was primarily due to the continued reliance on electricity generation from fossil fuels, such as coal and oil, for EV charging.
Associate Professor Stephen Poletti and doctoral candidate Simon Tao from the Business School's Energy Centre noted that, despite increased EV uptake, the global reduction in CO₂ emissions has been minimal.
On the contrary, EV adoption is positively associated with CO₂ emissions. This finding appears counterintuitive; it challenges the conventional belief that EVs contribute to decarbonization. Our analysis highlights that the environmental benefits of EVs are contingent on the composition of a country's electricity generation mix.
Simon Tao, Doctoral Student, Energy Centre, University of Auckland
Take EVs charged using electricity from coal-fired power plants, says Poletti.
In that case, they may indirectly contribute to higher emissions than modern gasoline or diesel vehicles, especially considering the entire lifecycle from production to disposal.
Stephen Poletti, Associate Professor, University of Auckland
The study's findings indicate that EV adoption will not significantly lower CO₂ emissions until the global share of renewable electricity generation reaches approximately 48 %.
According to Poletti, renewable energy sources, such as wind, solar, and hydro, are expected to account for just over 30 % of global electricity generation in 2023, highlighting the need for further progress in this area.
He added, “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.”
New Zealand, which generates over 80 % of its electricity from renewable sources, is positioned to benefit from the increased use of EVs.
“This research is a reminder that decarbonizing transport can't happen in isolation. 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,” Poletti noted.
Poletti suggests that investments in smart grids and transmission networks can enhance the efficiency and reliability of renewable energy supplies.
He added, “Policies should support community-based renewable energy projects, which can increase public acceptance of renewable energy installations.”
The researchers also argue that eliminating fossil fuel subsidies and implementing carbon pricing mechanisms could promote the development of renewable energy.
Tao stated, “Electric vehicle uptake can help countries meet climate-related targets, as long as the energy used to power them is clean.”
In addition to examining EV adoption, the researchers analyzed the impact of economic growth, green technology innovation, renewable energy usage, and population density on emissions.
They found that while economic growth increases emissions, innovation in green technologies and higher population density, such as in more compact cities, can help reduce them. The most significant reduction in emissions came from the use of renewable energy.
Journal Reference:
Tao, M. et al. (2025) Deciphering the impact of electric vehicles on carbon emissions: Some insights from an extended STIRPAT framework. Energy. doi.org/10.1016/j.energy.2025.134473