Plug-in hybrids, or PHEVs, combine regular hybrid technology with a plug-in system like that found on pure battery electric vehicles. Automakers view PHEVs as the halfway point between ICE vehicles and EVs. However, PHEVs still have combustion engines and thus produce C02 emissions. Automakers prefer not to acknowledge this but facts are facts, and now Reuters cites a report stating PHEVs produce more emissions than advertised.

A European campaign group calling itself Transport and Environment (T&E) has gathered the data and is now calling on governments to end PHEV subsidies and other tax breaks.

T&E's data comes from tests conducted by Emissions Analytics who studied three PHEV SUVs - the BMW X5 Hybrid, Volvo XC60 Hybrid, and Mitsubishi Outlander PHEV. The results indicated all three emitted more C02 than claimed even under optimal driving conditions.

"Plug-in hybrids are fake electric cars, built for lab tests and tax breaks, not real driving," Julia Poliscanova, T&E's senior director for clean vehicles said in a statement. "Governments should stop subsidizing these cars with billions in taxpayers' money."

In response, Mitsubishi and Volvo said that their respective PHEVs comply with all current emissions legislation. Mitsubishi even added independent testing might provide unreliable information depending on conditions. BMW has to comment. The timing of T&E's report also happens to follow a new European Union proposal that would see automakers forced to abide by even stricter emissions standards in order to be classified as a sustainable investment.

In addition, it calls for hybrids to lose their 'green' label beginning in 2026. A regular Toyota Prius may no longer be the green vehicle it has been for over 20 years. PHEVs have proven to be popular in Europe, accounting for nearly half of all-electric or semi-electric vehicle sales on the continent this year as buyers continue to take advantage of subsidies.

But the industry is shifting gears as a growing list of countries, including the UK, continues to propose the elimination of new combustion-engined vehicle sales completely within 15 years. In the US, the state of California wants this to happen by 2035, and other states are expected to follow suit.