Vehicle emissions testing specialist Emission Analytics has highlighted how electric vehicles, that are thought to be a greener option, can sometimes actually be more polluting than the petrol and diesel models they are designed to replace.

This comes about not only because electric vehicles place increased draw on a power grid that will often not be zero emission, but also certain secondary effects of electrification.

Emission Analytics say that the most frequent concern with battery electric vehicles (BEVs) is that the additional weight compared to equivalent internal combustion engines leads to higher non-exhaust emissions, which may equal or exceed the eliminated exhaust emissions.  These non-exhaust emissions from the vehicle come from its brakes and tyres. For example they have calculated that a Jaguar I-Pace would emit 16% more tyre particle wear than the nearest equivalent Jaguar F-Pace, due to the 443kg additional overall weight.

As a reference, the maximum exhaust particle mass emissions permitted in the EU since 2009 is 5mg/km1.  Often, real-world emissions on vehicles with a particle filter are well below 1mg/km.  Therefore, for every 100kg of extra payload, the added tyre wear emissions may be as much as the maximum allowed out of the tailpipe in total, and more like five times more than the tailpipe emissions in practice.

Emissions Analytics have also conducted tests which have shown that electric and hybrid vehicles also have poorer quality in-car air due to added pressure on the filtration system. The average cabin air quality index from hybrids was 55% worse than other vehicles in a similar size grouping and requires greater energy consumption.

Emissions Analytics have also expressed concern that electric vehicles may also encourage a switch from public transport and this will impact on traffic congestion. As heavy vehicles are likely to remain petrol or diesel from many decades, this could also increase overall emissions.