7.7.2011 Comment: Electric body and soul

Whether or not the electric car succeeds in becoming the mainstream vehicle technology of the twenty-first century, electrification has already left its mark on power-train design.

With early innovations including the starter-motor and alternator, the performance of the humble combustion engine has been improved beyond recognition with the addition of electric wizardry, ranging from 'start-stop' to full hybrid drive.

The electric car's 'trail of disruption' is also challenging vehicle policy and regulation. With zero-emission vehicles now a commercial reality, tailpipe-focused taxation makes little sense when there isn't a tailpipe, the emissions being generated away from the vehicle. Non-standard materials used for battery and motor production, such as lithium and rare-earth elements, also cast doubt on the assumption that vehicle manufacturing emissions can be ignored. (They currently contribute around 15% for conventional vehicles.)

In a report just published for the Low Carbon Vehicle Partnership, Ricardo observes that "current tailpipe comparisons of car CO2 emissions will become increasingly inappropriate with the introduction of lower carbon car technologies." They conclude that the development of a new life cycle metric is required to allow a realistic comparison of new vehicle technologies; one that includes both 'well-to-wheel' fuel emissions, and the embodied energy used for vehicle production.

The study concludes that, on a life cycle basis, electric vehicles do reduce carbon emissions relative to conventional vehicles (by around 20%), but by far less than is predicted by considering fuel use alone (around 40%). The difference is due to the higher emissions associated with the production of plug-in vehicles, which for battery electrics can account for as much as 46% of the total life cycle carbon. (Embodied carbon emissions for hybrids and fuel cell cars is estimated at around 30%.)

While consumer interest in vehicle emissions is growing, car buyers are becoming increasingly savvy about manufacturers' green claims. A full life cycle metric that both represents real-world driving impacts and can accommodate new technologies can therefore perform an important function in providing an independent accreditation of new technologies – and is why we developed the Green Car Rating at nextgreencar.com.

In transferring some of their capabilities to conventional vehicles, battery electrics could be their own worst enemy. However, it may turn out that their greatest legacy will be a lasting impact on power-train design, on technology policy, and on environmental regulation. Whatever the future of electric vehicles, their soul will certainly live on.

© Dr Ben Lane, nextgreencar.com

Article also appears in the July edition of GreenFleet Magazine