Plug-in hybrid owners, you do not have to feel guilty for having one after reading that they can be more pollutant than they should. As we mentioned in that article – and for the time being – it is just a matter of preventing your car from taking control of the best driving mode. Use it in EV mode as much as possible. When you decide to buy a new one, you can choose one that fits what T&E (Transport & Environment) recommends.

Apart from pointing out how polluting PHEVs can be, T&E also suggested to InsideEVs fundamental changes to make these vehicles exactly what they propose to be: a safe transition from combustion-engined vehicles to all-electric cars instead of a way to conceal big engines.

Emissiongate For PHEVs? T&E Claims They Pollute More Than They Seem

According to Anna Krajinska, emission engineer at T&E, there are three aspects that PHEV manufacturers have to address urgently: motors, battery pack, and charging capacity.

“The average electrical power of PHEVs on sale is less than half – 43 percent – of the power of the internal combustion engine fitted to the car. That means that current PHEVs are closer to conventional ICE cars than BEVs. To improve PHEVs, manufacturers should ensure that the electric power of the car is at least equal to the power of the internal combustion engine by fitting more powerful electric motors to PHEVs. The car should be able to drive at least 80 km electrically, stay in electric-only operation under all conditions, and be capable of fast charging.”

As you are probably aware, very few PHEVs have a fast-charging capability, and most of them fire up the combustion engine just to make up for their small battery packs. This is one of the reasons why PHEVs have emitted carbon in T&E’s emission tests, even if not the only one.

“During T&E's tests, it was found that both the XC60 and X5 switch on the engine when more power – due to faster accelerations – is demanded, decreasing the EV-only range by up to 76 percent. Similarly, while it was not seen on T&E's tests, the Outlander PHEV manual states many conditions under which the engine can turn on automatically, including if the car is not regularly refueled, despite having a charged battery.”

Exhaust pipe emissions

Apart from these situations in which the car demands the engine to work, T&E made its tests under the RDE (Real Driving Emissions) test procedure for 92 km (57.2 miles). That is a longer distance than most PHEV ranges, which implies they will have to switch their engines on anyway, as Krajinska told InsideEVs.

“After 75 km (X5), 37 km (XC60), and 48 km (Outlander), the internal combustion turned on, and therefore CO2 emissions were measured on this test.”

2019 Mitsubishi Outlander PHEV First Drive: A Shocking Bargain

Although the Outlander PHEV is the one with higher emission levels in EV mode, it is one of the most efficient in hybrid and battery charging modes. That's because its combustion engine can also work as a generator instead of solely to power the car, as we told you when we reviewed it.

Summing up, PHEVs should be more like EVs. If a big battery pack is an issue, due to costs, carmakers could reduce it by having an engine solely for charging it. That’s something Nissan has proposed to do with the e-Power system. Its penalties are a tiny battery pack and no charging port – which makes these cars look just like more efficient hybrids instead of the electric cars powered by gas Nissan wants customers to define them as.


Obrist went a little further: it developed an affordable and efficient zero vibration engine to feed the battery pack of a PHEV based on the Tesla Model 3. Such an arrangement could cost as little as €20,000 –$23,839 at the current exchange rate. The Obrist Mark III will be an interesting machine.

With T&E’s suggestions in mind, you can avoid the trap PHEVs may become if they keep on using powerful engines instead of powerful and clean motors. You will also manage to dodge poor charging infrastructures with more peace of mind – especially if you have access to renewable fuels in your country. In case you cannot buy an all-electric car, make sure you choose the best PHEV you possibly can.

Got a tip for us? Email: