Introduction

Plug-in hybrid electric vehicles (PHEVs) connect two energy systems—the electric power network and the transportation sector—in ways that could provide significant public health benefits.

To begin, it is important to distinguish between three types of vehicles: conventional cars, hybrid electric automobiles and PHEVs. Most modern automobiles employ internal combustion engines fuelled by gasoline or diesel that start quickly and provide power as soon as drivers need it, but operate inefficiently and waste energy when idling and braking. Hybrid electric vehicles add a larger battery and an electric motor in addition to a normal engine. Commercially popular models include the Toyota Prius and the Honda Insight. PHEVs employ hybrid electric vehicle technology, but feature an even larger battery and a plug-in charger and can usually travel 20–60 miles (30–100 km) on electricity alone. PHEVs, by coupling advanced power electronics and computer controls with conventional and electric drive trains, tend to operate more efficiently than ordinary automobiles. Unlike hybrid electric vehicles, PHEVs can recharge from the power grid and travel moderate distances on electricity alone, without using the internal combustion engine. PHEVs lessen fuel usage because they draw from the electric motor (especially in slow traffic or all-electric mode), minimise use of the internal combustion engine when the vehicle has stopped and recapture otherwise discarded kinetic energy during braking.1

While this may sound rather dry to those in the medical and health professions, it should not. By relying on vehicles that draw on power from the grid instead of directly combusting fossil fuels, a transition to PHEVs could significantly mitigate air pollution, and the morbidity and mortality associated with particle pollution, ozone and climate change.