Plug-in hybrid vehicles are powered by an electric motor using a battery that is recharged by being plugged in or via an on-board gasoline or diesel engine. They account for 3% of new car sales in the UK. Analysis from pressure groups Transport and Environment and Greenpeace suggest they emit an average of 120g of CO2 per km. versus 44g per km in official "lab" tests
Plug-in hybrid electric vehicles are alternatives to more popular conventional hybrids, which can't be recharged by plugging them into an AC outlet. Plug-in hybrids can offer a 20- to 40-mile range as a purely electric vehicle, so are less polluting than other vehicles.
The official tests where plug-in hybrids emit an average of 44g per km of CO2 are conducted on a circuit and see vehicles driven in a way that regulators consider "normal". The pressure groups have analysed what they say is "real-world" data on fuel efficiency collected from some 20,000 plug-in hybrid drivers around Europe.
These are drivers who have chosen to record their mileage and fuel consumption for surveys or who drive company or leased vehicles whose fuel efficiency is recorded. According to this data-set the lifetime emissions of a plug-in hybrid average around 28 tonnes of CO2. The average gasoline or diesel car is estimated to emit between 39 and 41 tonnes of CO2 from fuel during its lifetime. So a plug-in hybrid would only deliver an emissions reduction of about one third, far less than the official estimates.
Transport and Environment’s says a key problem with plug-in hybrids is many owners rarely charge their cars, meaning they rely on the petrol or diesel engine. Many plug-in hybrid models automatically turn on the gasoline or diesel engine at start-up on a cold day, or will kick in that engine if driver accelerates hard.
"If you always charge the battery and tend to do lots of short journeys, they (plug in hybrids) will have very low emissions", says Nick Molden, who runs Emissions Analytics, a company that specializes in vehicle emissions evaluation. "If you never charge the battery and drive very aggressively then they can have significantly higher emissions than the equivalent petrol or diesel model." https://www.bbc.co.uk/news/science-environment-54170207
This has nothing to do with fake tests by the manufacturers. But ... the BBC forgot to explain how an EVs’ formal miles-per-kWh and range are assessed.
“… the car is ‘soaked’ overnight in an air-conditioned chamber at 18deg C while plugged in to ensure all cars are in the same state when the test commences.”
“The driving part of the test is only conducted when the ambient air temperature is between 10 and 15deg C.”
“All driving is done at What Car?’s private test track, so traffic conditions don’t affect the result. However, the 19.4-mile route simulates a mix of stop-start urban traffic, rural roads and motorways.”
https://www.whatcar.com/news/what-car-real-range-how-we-work-it-out/n18158#3
The tests are obviously not hilly routes, during wet cold January evenings with heater, lights and windshield wipers operating. You can't rely on battery power for long on a cold day, or when you drive aggressively.
Transport and Environment’s says a key problem with plug-in hybrids is that so many owners rarely actually charge their cars. Even though charging is a much cheaper alternative to gasoline or diesel fuel purchases. Maybe they can't charge at home? Maybe they don't want to waste time using public chargers? Maybe they are virtue signaling by showing others they own a plug in hybrid?
"This is why people don’t charge at home: I currently drive a VW Passat Estate 2.0l diesel. The latest version of this car attracts company car tax for a 20% tax payer of £1804 or £150 a month. The VW Passat Estate GTE hybrid attracts company car tax of £765 a year or £63.75 a month. I therefore want the hybrid as my next company car. Now I can charge it at home but I also have to pay my company 15p a mile for personal use. So why would I pay to charge the battery at home from my own pocket for business mileage? Since I don’t pay for fuel, just the 15p a mile, why would I charge it at home for personal usage out my own pocket and still pay 15p a mile? Unless I can come to an arrangement with my company to compensate me for home charging I’m not going to do it. So the tax system encourages hybrids for company car drivers but there’s no incentive to spend your own money to charge it. That’s why they are never charged".
JCalvert
The physics of hybrid vehicles is strange.
(1)
You haul heavy, unused batteries when you are driving using fossil fuels ... and when using the batteries, you have haul a conventional engine for the ride. The added weight of batteries to get a 40 mile, or 64 km, electric range is about 800lbs. or 365 Kg, plus an added cost of nearly $8,000. Even if an electric vehicle rebate was available, this only makes sense if the car is mostly driven on short trips, and you have access to an electric charger at work or home. If that’s the case, a pure electric may make more sense.
(2)
Plug in hybrids are "carbon-efficient" only when the carbon cost of generating the plug-in electricity is left out of the equation. Pure non-hybrid electric cars would make sense if we had 100% nuclear powered electricity. But we don’t. One third of US power comes from coal -- two thirds in my area. A lot of electricity comes from natural gas. It would be more efficient to burn the natural gas directly in the car engine.
(3)
The regular non-plug in hybrid charging the battery from the engine will be emitting CO2 when it is doing that. But regenerative braking can charge batteries without CO2 emissions, especially in stop and go city driving.
The hybrid solution favored in Norway is to have an electric AND a diesel car. The electric gets all the subsidies, and is used on short local commutes, but most electric car owners also have a diesel 4×4 for long journeys, load carrying and cold weather. That pattern may be repeating in the UK.
The hybrids getting the biggest tax benefits are the really expensive ones with unnecessarily large power ratings. If there was a sliding scale of benefits, where, say, a small NIssan got 100% of the calculation, tapering down to 0% for a 2.5 tonne large German (pick your brand), there would be some logic in the process.
City air quality has improved a lot in the last 50 years. Modern internal combustion engine cars have very low pollution. During COVID lockdowns, with 80% less traffic, the air quality in cities did not change.
https://airqualitynews.com/2020/09/08/pm2-5-pollution-did-not-decline-during-lockdown-in-scotland/
There's no such thing as ‘clean’ energy. Manufacturing EVs, hybrids, batteries, wind turbines, solar panels etc. is very dirty and bad for the environment one way, or another.