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Plug-in hybrid cars: pros & cons

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Thinking of buying a plug-in hybrid car? Let’s look at all the main advantages and disadvantages of plug-in hybrids.

  • What is a plug-in hybrid car & how do they work? 

  • What are the advantages & disadvantages of plug-in hybrid cars?

    •  Advantages of plug-in hybrid cars

    •  Disadvantages of plug-in hybrid cars 

  • Are plug-in hybrid cars worth it?

  • FAQs

  • Power NI electric vehicle plan

What is a plug-in hybrid car & how do they work? 

Plug-in hybrid cars (also known as PHEVs) are cars that offer the financial and environmental benefits of electric cars combined with the flexibility and reassurance of a petrol or diesel engine. That’s because PHEVs have both an electric motor and a combustion engine. 

PHEVs are plugged in and charged at electric vehicle charge points. If the charge runs out during a journey, the car will simply start to use the combustion engine and run like a regular car.

Difference between hybrid, plug-in hybrid & electric vehicles:

  • Electric vehicles run solely on energy stored in a battery and electric motors. 
  • Hybrid vehicles have combustion engines and an electric battery that is charged by regenerative braking — energy created when the car brakes. 
  • Plug-in hybrid vehicles have a combustion engine and an electric motor that is plugged in to charge like pure electric vehicles. Plug-in hybrid cars can run for longer on electric power alone than standard hybrids — usually up to 50 miles — but their range isn’t as long as pure electric cars. PHEVs usually have a larger battery but smaller fuel tank than hybrid cars.

What are the advantages & disadvantages of plug-in hybrids?


There are a variety of advantages and disadvantages of plug-in hybrid cars when you compare them to other vehicle types. You’ll see some of the key pros and cons of PHEVs in the table below, and we’ll go on to discuss each of them in more detail.

Pros Cons
Reduced tailpipe emissions 

Fuel efficient for short journeys 

Lower tax costs 

No range anxiety

Easy transition to EV
Expensive to purchase

Poor fuel economy for long journeys

Maintenance costs 

Still rely on fossil fuel 

Losing relevance

5 advantages of plug-in hybrid cars 
Let’s explore the main advantages of plug-in hybrid cars. Here are some areas in which PHEVs have got the edge over the alternatives.

Reduced tailpipe emissions 
For as long as a plug-in hybrid car is running on its electric battery, it will release zero tailpipe emissions (just like a pure electric car). Absolutely no carbon dioxide or other greenhouse gases are emitted on shorter journeys, which makes PHEVs better for the environment than petrol, diesel and hybrid cars.

Fuel efficient for short journeys
Within the electric range of a plug-in hybrid car, you can save money on petrol and diesel. There are no fuel costs for shorter journeys when the car is running off its battery — just the significantly lower cost of charging your car. This will reduce the amount you spend on running your car for most journeys, with the average NI car journey in 2019 under 8 miles. 

Lower tax costs 
When you register a plug-in hybrid car, the first year road tax is usually £155. This compares to £210 for the average petrol car. For the second year onwards, PHEVs will pay around £170 per year (depending on emissions) while petrol and diesel cars pay £180.

No range anxiety 
For longer journeys — particularly in remote areas — the backup option of a petrol or diesel engine means you don’t need to worry about being stranded without a nearby charger. This alleviates what’s known as range anxiety  — the dread of running out of charge midway through a journey.

Easy transition to EV
PHEVs can be a simple way of making the switch to electric cars. You’ll build your understanding of how and when to charge while still enjoying the familiarity of a combustion engine. If you later make the move to a pure electric car, it will be a much smoother transition and you’ll know exactly what’s involved.

5 disadvantages of plug-in hybrid cars 
It’s not all good news when it comes to PHEVs. Let’s delve into the disadvantages of plug-in hybrid cars in comparison to pure electric cars, hybrid cars and conventional cars.

Upfront cost
Plug-in hybrid cars are usually more expensive to buy than equivalent petrol and diesel cars. The on-the-road price for PHEVs is also typically higher than for hybrid vehicles. If you’re buying on finance, your monthly payment will be higher for a PHEV.

Poor fuel economy for long journeys
Electric batteries are heavy. When a PHEV’s electric range runs out on longer journeys and the car reverts to its combustion engine, this additional weight leads to reduced fuel economy. You’ll usually get fewer miles to the gallon from a PHEV than a conventional petrol or diesel car.

Maintenance costs 
Since the technology is relatively new, electric cars have more expensive batteries and lower availability of both spare parts and suitably qualified mechanics. Combustion cars have cheaper parts but they have more moving parts and more things to go wrong. PHEVs — with an electric motor and combustion engine — come with the potential downsides of both.

Battery replacement 
As we mentioned in relation to maintenance, replacing the battery of a plug-in hybrid vehicle can be very expensive in comparison to new batteries for conventional petrol or diesel cars. It's worth noting that batteries are usually under warranty for at least 100,000 miles, so this isn’t an everyday problem.

Losing relevance 
We’re moving closer to 2030 and the ban  on the sale of new petrol and diesel vehicles in Northern Ireland. While plug-in hybrids have been given an extension until 2035, there is still a limited lifespan for this technology. There is an argument that PHEVs will lose relevance for manufacturers and drivers alike as that deadline gets closer.

Are plug-in hybrid cars worth it?

Whether a plug-in hybrid car is a worthwhile investment will depend on the type of journeys you plan to make. If you live in a town or city and typically make short journeys, PHEVs are a great way of enjoying all the benefits of electric vehicles over shorter distances. Similarly, if you still have some reservations about moving towards electric vehicles, PHEVs can be a useful stepping stone. 

The sale of new PHEVs will be banned from 2035, but plug-in hybrid vehicles are likely to retain a high resale value for the foreseeable future as more people move away from conventional petrol and diesel cars.


What happens if you don't charge a plug-in hybrid? 
If you don’t charge a plug-in hybrid, you can still drive it as you would a conventional car. Although it is designed to be plugged in to charge, the battery has some self-charging capability. This allows the car to drive like a petrol or diesel car even when it hasn’t been plugged in. 

At what speed do plug-in hybrid cars switch from battery power to petrol power?
Plug-in hybrids can use battery power at any speed. While hybrid cars can only power a car at lower speeds, PHEVs can use their electric battery even at high speeds. This is due to the different ways in which the battery is charged.

Does the UK 2030 ban on petrol & diesel cars affect plug-in hybrids?
While the sale of new petrol and diesel cars in the UK is banned from 2030, plug-in hybrids have been given an extension. Car manufacturers will be able to sell plug-in hybrid vehicles with the “capability to drive a significant distance with zero emissions” until 2035.

How long do plug-in hybrid batteries last?
Plug-in hybrid batteries will typically last up to 10 years or 100,000 miles. Some vehicle owners have reported PHEV batteries lasting much longer than this — even up to 200,000 miles. Batteries will usually be under warranty for around 100,000 miles, so you should be covered if you experience problems before this.

Does a plug-in hybrid charge whilst driving?
Some plug-in hybrid vehicles self-charge when you brake in the same way that hybrid cars do. Others don’t have this regenerative braking capability. In reality, its impact is minimal in comparison to plugging in the vehicle to charge it. All PHEVs self-charge to some level so that they can run as combustion cars when there is no electric charge.

Should I charge a plug-in hybrid every day?
That will depend on how often you’re using the car and how far you drive. If you use all or most of the electric range every day, it makes sense to top it up regularly to give yourself the full zero-emission, high-efficiency range of electric miles.

Power NI electric vehicle plans 

We’re committed to helping drivers in Northern Ireland move towards a green future and electric vehicles. Whether you’re planning to buy a plug-in hybrid or pure electric vehicle, we’re here to help you.

Choose from our special EV tariffs to enjoy cheaper electricity rates for overnight charging with the equivalent of 100% of the electricity you use sourced from renewable generators. We also offer the world’s smallest smart home charger for discreet and convenient plug-in charging.