Study sheds new light on impact of electric cars on global warming

The results of a modelling exercise, conducted by Professor Malcolm McCulloch who heads up the Department of Engineering Science Energy and Power Group, and the Department’s former DPhil student, Reed Doucette, shows that in some countries electric cars could accelerate global warming.

Professor Malcolm McCullochProfessor McCulloch highlighted that ‘by 2050, we will live in a world of where climate change is a visible reality and where global energy supply could be constrained. It is clear that highly efficient and low carbon energy systems are vital in meeting these challenges. There needs to be a public awareness of the seriousness of the problems’.

Professor McCulloch said: “Given that the number of vehicles on the world’s roads is expected to grow to 2.9 billion by 2050, battery electric vehicles (BEVs) are being increasingly examined as a way to reduce CO2 emissions in transport. This modelling exercise simulated the tank to wheel energy consumption of several BEVs and compared the CO2 emissions they would be responsible for to the tank to wheel CO2 emissions from similar internal combustion engines (ICE)-based vehicles. Amongst the results, it was shown that BEVs have the potential to more significantly reduce CO2 emissions relative to ICE-based vehicles when the CO2 intensity of ICE-based vehicles is higher. This study also showed that for countries with power generation mixes with a low CO2 intensity, BEVs have the ability to significantly reduce CO2 emissions from vehicles”.

Professor McCulloch added: “For countries with high CO2 intensities (such as China and India), BEVs can actually have higher operating CO2 intensities than similar ICE-based vehicles. Therefore, unless countries with power generation of a high CO2 intensity significantly decarbonize their power generation, BEVs may only slightly reduce or in some cases may even increase the CO2 emissions coming from automobile transport”.

For full results of this study please visit:

New tool

The Department’s Energy and Power Group has developed a detailed vehicle simulation tool called Oxford Vehicle Model (OVEM), which was used in this study. OVEM together with experimental data was used to investigate future drivetrain topologies, impact of different fuels, efficient driving styles and relationship between technology performance, consumer choices and policy.

Tipping Point

Professor McCulloch believes that developing the technology is only the start. There needs to be a public awareness of the seriousness of the problems. Therefore he has been instrumental, together with a small team of people, in conceiving and developing Tipping Point, an annual event to bring some of the top artists and climate scientists together. Through the creative use of the open space format, this forum has proved to be extremely successful and has found international acceptance.

Professor Malcolm McCulloch has also presented the research to a wide range of audiences, from schools to the World Economic Forum in China.

About the Energy and Power Group

The Department’s Energy and Power Group focuses on developing innovative electrical and mechanical engineering tools and techniques to enable the development of smart, highly efficient, high performance energy system components. The Group has a strong focus on creating impact through industrial collaboration and spin-out activities.

Forthcoming event: Professor McCulloch will be talking on "Sustainable transport: electric dreams vs carbon reality" on 21st May 2015 at the Oxford Martin School in Oxford. For more information please visit: