In a market where just about every car manufacturer seems to be promoting ‘electrified’ models, it can be hard to decipher just exactly what technology they’re referring to. In this article, we’ll be taking a look at hybrid cars and running through some of the benefits and drawbacks of this technology.
The word ‘hybrid’ can mean various different things in the car industry, which can be very unhelpful to customers. The general idea is that it refers to a vehicle that has both an internal combustion (petrol or diesel) engine and an electric motor, rather than just one or the other. But that’s just a starting point.
Broadly speaking, there are three recognised categories of hybrid vehicles: regular hybrid, mild hybrid and plug-in hybrid. This article will concentrate on the regular hybrid, which is the original hybrid vehicle and has been around for almost 30 years now.
Thanks to car company marketing jargon, regular hybrid cars may be known as full hybrids or (falsely) ‘self-charging’ hybrids. You may also see the abbreviation HEV, which stands for hybrid electric vehicle and is also misleading (it’s still predominantly a petrol vehicle, not an electric vehicle).
[Here at The Car Expert, the only descriptions we accept are regular hybrid or basic hybrid. All the rest is misleading marketing crap – ed]
A regular hybrid pairs a petrol (or, rarely, a diesel) engine and an electric motor, which gets its energy from a small battery. The car can drive on either petrol or electric power, or a mix of both at the same time.
The battery cannot be plugged into an external source, so all of its electricity comes either directly or indirectly from the petrol engine. We’ll come back to that shortly. A hybrid can run on its electric motor for a few miles without using the petrol engine, but only if you’re being gentle with the accelerator.
Other types of hybrid
There are two other types of hybrid that you may encounter: the mild hybrid and the plug-in hybrid.
A mild hybrid uses a small electric motor to assist a petrol or diesel engine, taking on some of the load to reduce the work that the engine has to do. This improves a car’s performance and/or fuel economy, but usually not by much. A mild hybrid can’t run on electric power alone as the electric motor is not connected to the wheels – it simply acts to support the engine. There’s also usually no battery, so the electric motor relies on the petrol/diesel engine to generate its electricity.
Here at The Car Expert, we generally don’t bother mentioning mild hybrids as they tend to provide very little practical benefit, and you drive the car like a conventional petrol or diesel vehicle anyway. We will usually describe a mild hybrid car as “a petrol (or diesel) car with mild hybrid assistance” as it’s more accurate.
A plug-in hybrid works similarly to a regular hybrid but is more developed in every way. The battery is bigger and, as the name suggests, can be plugged into an external charging point. That means you can charge the car at home or at a public charging point to fill up the battery, which you’ll need to do if you want to maximise the benefit of having a larger battery.
The electric motor is also usually bigger and more powerful, so can take more of the driving load on its own. Most plug-in hybrids can do at least 20 miles just on the electric motor and battery without calling on the petrol engine, and some of the latest models can do more than 50 miles.
How does a hybrid system work?
A regular or plug-in hybrid has two power sources to drive the car: a petrol engine and an electric motor. There have been some diesel hybrids and plug-in hybrids over the years, but very few (Mercedes still perseveres with them today, but most other manufacturers have given up on diesel altogether).
Depending on your driving circumstances and how much electricity is in the battery, the car can drive as a regular petrol car, a fully electric car, or use both sources at the same time for maximum performance. By using whichever power source gives the best result for your current driving need, a hybrid can maximise efficiency to reduce CO2 emissions and fuel bills. However, its effectiveness will depend on the sophistication of the car and how well it integrates petrol and electric motors. Newer hybrids do this much better than older models, giving a much better driving experience and better fuel economy.
The battery supplies electricity to the electric motor. While a plug-in hybrid allows you to connect the car to an external charger, a regular hybrid doesn’t have a plug so you can’t do that. Car companies also use misleading phrases like “no need to plug in!” when talking about a regular hybrid, as if that’s some kind of advantage. It’s not. It just means that the electricity has to come from the car itself, which it achieves in two ways.
Firstly, whenever you coast or brake in a hybrid vehicle, the car is able to generate a small amount of electricity that is sent to the battery. This is called regeneration, and what car company marketing people describe as “self-charging” and act like it’s magic. In reality, all you’re doing is recouping a small percentage of the energy you’ve already spent accelerating the car in the first place. So you might spend ten units of fuel energy to accelerate your car from rest to 30mph, and then get one unit of electrical energy back again as you slow back down to a stop. The electricity you’ve gained has been provided indirectly from the petrol engine.
Secondly, the car can use the petrol engine as a generator, burning petrol to create electricity. This is often described as forced regeneration. Some hybrid cars will have a button in the cabin somewhere that the driver can use to activate this function, while other cars handle it automatically.
How does a regular hybrid compare to a plug-in hybrid?
A regular hybrid system features a battery large enough to drive the vehicle using electric power only for short periods of time. That means a few miles, at most, before you run out of electricity in the battery and the petrol engine needs to take over.
Unlike plug-in hybrids, which have a quoted electric-only driving range, regular hybrids don’t tend to have a specified electric-only range. They excel on urban routes, managing the use of electric power and petrol power as necessary. Because you’re stopping and starting regularly, it maximises the regeneration of electricity to the battery, helping to improve your overall fuel economy. And when the car is running on purely electric power, it is usually much quieter and smoother than running as a petrol car.
When a hybrid is travelling at motorway speeds, it generally relies on the petrol engine alone while the electric motor is not used – so you’re effectively carrying a couple of hundred kilograms of ballast from a motor and battery that are not being used. That means your motorway fuel economy may not be as good as a pure petrol car.
A plug-in hybrid usually has a more powerful electric motor, so it can handle more of the driving duties – even at motorway speeds, if there’s juice in the battery. It still probably won’t be as economical for long-distance motorway cruising, however.
Regular hybrids are likely to be a better option for drivers who don’t have easy access to charging, since you’re not going to get the benefit of a plug-in hybrid if you can’t plug it in. If you do have access to home or work charging, a plug-in hybrid will give you more electricity more cheaply, which will significantly reduce your running costs.
Do hybrid cars use petrol?
Most hybrid cars have a petrol engine as their primary source of power to turn the wheels. There have only been a small number of diesel hybrids over the years (a few more diesel plug-in hybrids) as diesel engines are not as well suited to regular start-stop behaviour, so they don’t deliver the same level of economy and emissions benefits in a hybrid format.
As well as using the petrol engine to drive the car, hybrids can also use it to charge the battery, which then provides electricity to power the electric motor.
The amount of petrol you use, relative to the amount of electricity, will depend on a few factors such as your driving style, the driving environment and the car itself. If you’re driving gently in an urban setting and your car has an efficient electric motor, you will spend more of your journey using electrical power instead of petrol power. But when you put your foot down hard on the accelerator, or head out onto a motorway, you’ll be driving a petrol car.
What are the pros and cons of a hybrid car?
Having both a petrol engine and an electric motor can offer either the best of both worlds, or the worst of both worlds. For a regular hybrid, here’s an idea of some of the the pros and cons compared to a regular petrol car.
Pros
- Better economy than a petrol car in urban driving
- Smooth, quiet EV driving at low speeds
- Lower emissions rating than an equivalent petrol car, which usually means lower road tax bills
- Some benefits of a full EV without needing access to a charging point or changing your driving habits
- Combined petrol and electric power provides additional performance
- Relatively simple to provide part-time four-wheel drive, using petrol motor to drive front wheels and electric motor for the rear wheels (or the other way round)
Cons
- Motorway fuel economy no better than a petrol car, and often worse
- Transition between electric and petrol power under acceleration can often be clunky
- No manual gearbox option
- Very limited electric driving range thanks to small battery and electric motor
- Boot space and/or rear cabin space often compromised to fit battery and associated components
- Higher maintenance costs than equivalent petrol car, which can offset fuel savings
Are hybrid cars becoming more popular?
As part of the global transition from fossil fuels to electric vehicles, governments around the world are encouraging people to buy electric vehicles. But while EV sales are steadily growing, there’s no doubt that a percentage of the car buying public is still not ready to make the leap from pure petrol or diesel power to pure electric power. If that sounds like you, a hybrid may be a good compromise.
Here in the UK, sales of new hybrid and plug-in hybrid cars are growing, pretty much directly at the expensive of petrol and diesel cars.
As of mid-2025, petrol cars now make up about half of all new car sales, a market share that is steadily declining. Diesel cars are almost extinct in new car terms, making up less than 5% of the market. Electric cars make up nearly 25%, regular hybrids about 15% and plug-in hybrids 10%.
By contrast, if you look back to 2017, diesel sales made up more than half of all new car sales, with petrol taking another 40%. EV, hybrid and plug-in hybrid made up less than 10% of all sales.
We’re probably at the period of peak hybrid in terms of new car sales. According to the government’s roadmap, EVs are targeted to make up 80% of all new car sales by 2030, with the remaining 20% split between regular and plug-in hybrids. They will then be phased out from new car sales by 2035.
When will new hybrid cars be banned in the UK?
The UK government is banning the sale of new petrol and diesel cars from 2030. Regular hybrids and plug-in hybrids can still be offered until 2035. There is no plan to remove used cars from UK roads, so these dates only apply to the sale of new cars.
Under the previous Conservative government, the rules around which hybrid cars would be permitted to be sold after 2030 were unclear. The Labour government has confirmed both plug-in hybrid and regular hybrid cars can be sold until 2035, after which time only electric cars will be allowed.
Additional reporting by Stuart Masson
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