T&E and ICCT analyses highlight PHEV emissions problem
Bigger PHEV batteries is not a viable solution
Automatic emission-free city driving solves a regulatory hurdle, it does not address the core emissions problem
According to Transport & Environment (T&E), a Brussels based think-tank, tests confirm that plug-in hybrid electric vehicles (PHEVs) pollute significantly more than automakers claim. “Plug-in hybrids are fake electric cars”, claims Julia Poliscanova, senior director for clean vehicles at T&E: “Our tests show that even in optimal conditions, with a full battery, the cars pollute more than advertised. Unless you driven them softly, carbon emissions can go off the charts. Governments should stop subsidising these cars with billions in taxpayers’ money”.
PHEVs combine an electric and a conventional combustion engine drive train. However, they typically contain small battery packs, compared to full-battery electric vehicles (BEVs), which do not tolerate long emissions free range. Furthermore, the battery pack weighs down the car so that when driven on conventional diesel or gasoline, fuel efficiency falls further.
A September 2020 whitepaper by The International Council on Clean Transportation (ICCT) makes an in-depth analysis of real-world usage of PHEVs, and related fuel consumption, electric driving, and carbon dioxide emissions. This paper, comes to the same conclusion, but recommends that vehicle manufacturers “should increase the all-electric range of their PHEVs from an average of about 50km today to a level of about 90km in future years”, as this would “be sufficient to cover the full daily distance driven electrically on about 85% of driving days or approximately 70% of total distances driven by German private car owners if charged every day”.
Even if PHEV battery pack sizes increase to cover a typical daily driving distance – which in itself varies widely by country and region – these vehicles are inherently inefficient. On one hand, the combustion engine carries around significant battery weight, at the same time as the battery drive carries deadweight in the form of a combustion engine. On the other, buyers face the problem of combustion engine issues as well as battery pack issues. An environmentally conscientious PHEV owner would likely charge the battery to maximum capacity on a daily basis, which leads to faster lithium-ion battery degradation. He or she would also have to battle the usual internal combustion engine problems of broken valve seals, holes within cylinders, faulty piston rings and an assortment of other issues.
Some automakers, including BMW, have advertised ‘automatic emission-free city driving’. This involves an “automatic switchover to purely electric operating mode” when entering pollution restriction areas (typically urban environments). While this solves a regulatory issue for drivers, it does not address the core emissions problem.