Report Proposes Smaller Gas Tanks to Boost Plug-In Hybrid Charging
Transport & Environment argues capping tanks at 15 liters would force PHEV owners to rely on electric power.
European clean transport advocacy organization Transport & Environment (T&E) is proposing that policymakers incentivize plug-in hybrid electric vehicles (PHEVs) with significantly smaller fuel tanks to encourage drivers to charge more frequently. The organization argues that limiting gas capacity would make electricity the primary power source and relegate gasoline to a backup role.
What Happened
T&E recommends capping PHEV fuel tanks at 15 liters, approximately four U.S. gallons, as part of a broader set of criteria designed to improve real-world performance. The group also calls for a minimum of 200 kilometers (124 miles) of real-world electric range by 2030, DC charging power exceeding 100 kilowatts, and electric motors with at least three times the power of the combustion engine. According to the report, these specifications would ensure that the vehicle behaves primarily like an electric car, using the internal combustion engine only when necessary.
Why It Matters
The proposal addresses a significant discrepancy between official estimates and actual emissions data. An analysis of European Environment Agency data revealed that PHEVs registered in 2024 emitted nearly six times their official CO₂ figures, a worsening trend from the five-times gap seen in 2023 models. While official figures suggested an 83% reduction in emissions compared to conventional cars, real-world emissions were only 14% lower. Pure-electric driving accounted for just 27% of the distance traveled, and the combustion engine ran during 32% of charge-depleting kilometers. T&E noted that PHEVs powered predominantly by fuel incur higher annual running costs, with 2024 models costing an estimated €1,810 annually to operate versus the €1,130 suggested by official consumption figures.
The Bottom Line
T&E’s recommendations aim to close the gap between theoretical and actual PHEV efficiency by forcing a shift in driver behavior through hardware constraints. While stricter EU emissions calculations are already pushing automakers to increase electric range, such as the Volkswagen Tiguan eHybrid’s jump from 55 km to 119 km, the organization warns that freezing future corrections could understate real-world emissions by 56%. The proposed changes remain recommendations for policymakers rather than implemented regulations.
