An Abundance of Choice - Powertrain Options Explained

There has never been more choice of powertrains than there currently is, and the SMMT recognises only five powertrain options in its reporting, but that isn’t all the choice available because there is more to it. We look into it all and explain the pros and cons for each.

Official Powertrain Choices

• Petrol - Runs only on petrol power. Prices of fuel vary.

• Diesel - Runs only on diesel power. Prices of fuel vary.

• HEV - Hybrid Electric Vehicle
  - Small battery and electric motor. Petrol engine does all the work, but combined saves fuel.

• BEV - Battery Electric Vehicle
  - Large high-voltage battery and motor, but smallest running costs with home charging and an EV tariff. Requires a home charger.

• PHEV - Plug-in Hybrid Electric Vehicle
  - Medium-sized high voltage battery, motor and engine. Does short journeys on the BEV powertrain and long journeys on the petrol/diesel engine. Requires home a charger to fully benefit.

There are many more choices than those that are reported, and what the SMMT doesn’t report I’ve rolled into sub-categories, and it’s these subcategories that we’ll dive into.

Sub-Categories

• Petrol MHEV - Mild Hybrid Electric Vehicle (subcategory to Petrol)
  - Small electric motor
  - 48-volt battery
  Usage: For improving fuel efficiency, cutting emissions, assist with acceleration.
  Application: Drives like a regular petrol car.
  
  Pros: Improves fuel efficiency slightly
  Cons: Doesn’t save much money on fuel
  

• Diesel MHEV - Mild Hybrid Electric Vehicle (subcategory to diesel)
  - Small electric motor
  - 48-volt battery
  Usage: For improving fuel efficiency, cutting emissions, assist with acceleration.
  Application: Drivers like a regular diesel car.
  
  Pros: Improves fuel efficiency slightly
  Cons: Doesn’t save much money on fuel
  

• REX - Range Extender (sub-category to PHEV)
  - Electric Motor for propulsion
  - Small High-voltage battery
  - Petrol engine generator doesn’t drive the wheels

  Usage: Full EV experience, requires plugging in like an EV and an occasional refill of petrol
  Application: Has a back-up fuel tank to eliminate EV range anxiety
  
  Pros: Mostly driven in BEV mode and best used with home charging & EV Tariff
  Cons: The petrol generator will be used very rarely
  

• EREV - Extended Range Electric Vehicle (sub-category to PHEV)
  - Electric Motor for propulsion
  - Large High-voltage battery
  - Petrol engine generator doesn’t drive the wheels

  Usage: EV experience and best used when charged at home with an EV tariff.
  Application: Maximum range combing petrol and electric power, could be good for towing.
  
  Pros: Alternative to diesel, but even lower on running costs. Good for long distance drives
  Cons: Still requires petrol so it will incur added fuel costs over a BEV
  

• Series Hybrid - (Sub-category to HEV)
  - Electric Motor for propulsion
  - Small High-voltage battery

  Usage: EV experience, petrol only power
  Application: For those who would like a HEV but with the BEV experience. No plugging in.
  
  Pros: More efficient than petrol power alone, but with an EV drivetrain
  Cons: All the running costs of petrol included, but with fewer benefits than a BEV
  

• FCEV - Fuel Cell Electric Vehicle (hydrogen car)
  - Electric Motor for propulsion
  - Small High-voltage battery
  - Hydrogen Fuel Cell

  Usage: Converts Hydrogen into electricity in-motion for the full EV experience.
  Application: Alternative to BEV, requiring cooled liquid hydrogen as a fuel source.
  
  Pros: Can be pumped in minutes, like refuelling a petrol car, for example
  Cons: Scarcity of filling stations, expensive fuel, expensive maintenance costs

With so much choice of powertrains available now - even more so now that Chinese manufacturers are entering the U.K. market at a pace - being informed is key to making the right decisions, especially as we cover so many cars here at Definitely Not A Guru.

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About the Author

Graeme Cobb is a lifelong car enthusiast with a passion for writing about cars, EVs, industry updates and more.

You can find Graeme on 𝕏 at @graeme_cobb or YouTube @REV-EV.