Glossary
Zero-emissions vehicle (ZEV)
A Zero-emissions vehicle (ZEV) is formally defined as a vehicle that emits no exhaust gases from its onboard source of power. As the name suggests, it creates zero tailpipe pollution, making a significant contribution to the improvement of air quality, especially in urban areas where the vehicle population density is high.
ZEVs, also known as ultra-low emission vehicles, encompass several renewable technologies and could potentially play a pivotal role in mitigating the negative environmental impacts associated with conventional combustion engine vehicles. These vehicle types are predominantly powered by electric motors, harnessing this energy from external sources such as the grid, or stored onboard in renewable forms like hydrogen.
Electric vehicles (EVs), fuel cell vehicles, and hydrogen combustion engine vehicles are prime examples of ZEVs, with each having distinct technologies that ensure zero tailpipe emissions. Electric vehicles store electrical energy in rechargeable batteries, while fuel cell vehicles combine hydrogen and oxygen to create energy, leaving only water as a byproduct. Hydrogen combustion engine vehicles combust hydrogen in an internal combustion engine, similar to a traditional gasoline car, but also produce water as the only emission.
The advent of ZEVs can be considered a significant milestone in green energy innovation, directly contributing to carbon accounting, an area focused on measuring and reducing greenhouse gas emissions. As ZEVs produce no direct carbon emissions, they offer a clear pathway to reducing the transport sector’s significant carbon footprint, thus supporting global decarbonization efforts. Their popularity continues to grow alongside a supportive policy landscape, improved battery technology, and the proliferation of charging infrastructure.
However, it is essential to note that while ZEVs emit no direct tailpipe emissions, indirect emissions are often associated with their use. These could be from the production of the electricity used to charge EVs or the extraction and processing of hydrogen, depending on the energy mix of the region. Therefore, although ZEVs represent a major leap towards an environmentally friendly transport sector, the overall carbon intensity of their lifecycle usage is dependent on the green credentials of the broader energy ecosystem.