Flawed hybrid car efficiency data to stifle UK EV sales and propagate pollution

Auto Express

19-05-2025

The government's decision to permit the sale of hybrid-powered vehicles post-2030 has the potential to increase carbon emissions and stifle the sales of EVs, according to a leading transport sustainability group.
Following the review by Labour into the ZEV Mandate – a set of rules which not only dictates the phase-out date for internal-combustion engined (ICE) vehicles, but also how many EVs must be sold per year up to that point – full-hybrid and plug-in hybrid cars will now be allowed to be sold from new between 2030 and 2035. Advertisement - Article continues below
However, The European Federation for Transport and Environment (T&E), says that the decision to consider plug-in hybrids as low-emissions and thus suitable to be sold after 2030, was based on what it describes as 'flawed' data that 'dramatically understate[s] the true emissions of PHEVs'.
Recently, it was highlighted that emissions data for plug-in hybrid cars on the WLTP test cycle were largely unrealistic and not representative of what most buyers achieved on the road.
T&E says that, on average, the real-world emissions of a plug-in hybrid car are typically three-and-a-half times higher than what the official figures suggest.
Such a disparity is much greater than that for petrol or diesel cars. This has largely been put down to the fact that PHEVs are tested with a charged battery and because tests take place over a short distance, the effectiveness of the battery and accompanying electric motor is overstated. A stricter test cycle has already been introduced, with a new, more representative set of regulations due to be introduced in 2027 that will better reflect real world driving. Skip advert Advertisement - Article continues below
Despite this, the government has stated that emissions targets for manufacturers will continue to use the old figures and test cycle. This, T&E fears, means that drivers will continue to be 'misled by the 'low emission' image of PHEVs portrayed by carmakers' and that the UK may struggle to hit its lofty climate targets as a result.
In fact, the European transport sustainability group believes this mixed messaging surrounding PHEVs could see as many as 500,000 additional new cars using the tech hitting the road by 2030, in turn jeopardising the sales of cleaner, fully-electric cars.
T&E has called on the government to bear in mind the new updated plug-in hybrid emissions figures and regulations before pressing ahead with its ZEV mandate changes to avoid 'duping' the public.
Such a sentiment is backed by Professor of Business and Sustainability at the University of Cardiff, Peter Wells, who told Auto Express that T&E's analysis was 'entirely correct, both in terms of the real-world performance of PHEVs, and the actual cost to consumers. It is a flawed policy.'
Wells continued, saying: 'We too easily forget that the point of all of this is to slow down the rate of climate change. Once again the government has allowed itself to be distracted by short-term economic expediency.'
Auto Express has approached the UK Department for Transport for comment, but we have yet to receive a response.
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