What is a hybrid car and how do they work?

Hybrid vehicles are more popular than ever and there is a huge selection of high quality new and used hybrid vehicles. Hybrids have a petrol or diesel engine and an electrical system that helps improve fuel economy and reduce CO2 emissions and can be a good choice if you want to switch from a petrol or diesel car but aren't ready to go full electric.

You may have heard of "regular hybrid", "self-charging hybrid", "mild hybrid" or "plug-in hybrid". All of them have common features, but there are also significant differences. Some of them can only run on battery power and some can't, and the distance they can travel on battery power varies greatly. One of them can be connected for charging, while the rest do not need it.

Read on to find out exactly how each type of hybrid car works, its pros and cons, and how it compares to others.

How do hybrid cars work?

Hybrid vehicles combine two different power sources - a gasoline or diesel internal combustion engine and an electric motor. All hybrids will help you improve fuel economy and emissions compared to vehicles running on gasoline or diesel only.

Most hybrid vehicles use an internal combustion engine as the main power source, with an electric motor providing additional power when needed. Many hybrids can be powered solely by the electric motor for short distances and at low speeds. Some of the latest examples can go much farther and faster on electric power alone, allowing you to commute to and from work without using the engine, saving money on fuel.

Toyota Yaris

What is a normal hybrid?

A conventional hybrid (or HEV) is also known as a "full hybrid", "parallel hybrid" or, more recently, a "self-charging hybrid". It was the first type of hybrid car to become popular and the most famous representative of this type is the Toyota Prius.

These models use an engine (usually a gasoline engine) with electric motor support for power. They also have an automatic transmission. The electric motor can drive the car for short periods of time, usually a mile or so, but it is mainly used to assist the internal combustion engine. The engine battery is charged by the energy recovered when braking or using the engine as a generator. Thus, there is no need - and no possibility - to connect and charge it yourself.

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Toyota Prius

What is a hybrid plugin?

Of all the different types of hybrids, the plug-in hybrid (or PHEV) is gaining the most popularity. Plug-in hybrids have a larger battery and a more powerful electric motor than conventional hybrids, allowing them to travel longer distances using electric power alone. The range typically ranges from 20 to 40 miles, depending on the model, although some can do more and options are growing as new plug-in hybrids are released. Most of them have a petrol engine and all have an automatic transmission.

Plug-in hybrids promise much better fuel economy and lower CO2 emissions than conventional hybrids, which means they can lower your fuel costs and taxes. You need to charge the battery regularly using a suitable outlet at home or work, or a public electric vehicle charger for the plug-in hybrid to perform at its best. They also recharge while driving in the same way as a conventional hybrid - by recovering energy from the brakes and using the engine as a generator. They work best if you make mostly shorter trips, so you can make the most of the electric-only options. You can read more about how a plug-in hybrid car works here.

Mitsubishi Outlander PHEV

Plug-in hybrids combine the advantages of both a petrol car and an electric car. An electric-only model can cover the daily commute of most people without harmful emissions or noise. And for longer trips, the engine will go the rest of the way if you give it enough fuel.

Historically, the Mitsubishi Outlander has been the best selling plug-in hybrid in the UK, but now there is a model to suit most lifestyles and budgets. For example, every Volvo has plug-in hybrid versions, and brands like Ford, Mini, Mercedes-Benz and Volkswagen offer plug-in hybrid models.

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Plug-in Mini Countryman Hybrid

What is a mild hybrid?

Mild hybrids (or MHEVs) are the simplest form of a hybrid. It's basically a regular gasoline or diesel car with an auxiliary electrical system that helps start the car and assists the engine, as well as powering the main electrical system that controls the air conditioning, lighting, and so on. This reduces the load on the engine, which helps improve fuel economy and reduce emissions, albeit by a relatively small amount. The mild hybrid batteries are recharged by braking.

A mild hybrid system does not allow the vehicle to be driven using only electric power and therefore they are not classified as "proper" hybrids. Many car brands are adding this technology to their latest petrol and diesel vehicles to improve efficiency. Some people like to add the label "hybrid" to such cars, while others do not. You can read more about how a mild hybrid works here.

Ford Puma

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What benefits do hybrid cars offer?

You will see two main benefits of buying a hybrid car: reduced operating costs and less environmental impact. This is because they promise much better fuel economy and lower CO2 emissions while driving.

Plug-in hybrids offer the biggest potential benefits. Many promise official average fuel economy of over 200mpg with CO2 emissions below 50g/km. The fuel economy you get in the real world behind the wheel will depend on how often you can charge your battery and how long your trips are. But if you keep the battery charged and take advantage of the battery-powered electric range, you should see more mileage than an equivalent diesel car. And because exhaust emissions are so low, the vehicle excise (car tax) costs very little, as does the in-kind tax for company car drivers.

Conventional hybrids offer the same benefits - fuel economy at least as good as diesel and lower CO2 emissions. They also cost less than PHEVs. However, they can only go a couple of miles on electric power alone, so while a conventional hybrid is good enough for a quiet ride at low speeds in cities or stop-and-go traffic, it probably won't get you to work, as some PHEVs can. without using an engine.

Mild hybrids offer slightly better economy and lower emissions than a conventional petrol or diesel car for about the same price. And they're becoming more common - it's likely that every new petrol and diesel car will be a mild hybrid in just a few years.

Is a hybrid car right for me?

Hybrid vehicles are a great choice and there are so many options to suit most buyers' needs. 

conventional hybrids

Conventional hybrids are a great alternative to petrol and diesel cars because you use them the exact same way. Batteries do not need to be charged, you simply fill the fuel tank as needed. They tend to cost more to buy than a petrol or diesel car, but they can provide better fuel economy and lower CO2 emissions, and therefore less car tax.

Plug-in hybrids

Plug-in hybrids work best if you can make full use of their electric range. To do this, you will need access to a suitable power outlet at home, at work or while traveling. They charge fastest with a suitable EV charger, although a three-prong outlet will do if you're not going to drive again for a few hours.

With this longer range, PHEVs can deliver extremely good fuel economy compared to an equivalent petrol or diesel vehicle. However, fuel consumption can increase significantly if the batteries are discharged. Official CO2 emissions are also usually very low in favor of your car tax, which can help offset the higher purchase price.

mild hybrids

Mild hybrids are essentially the same as any other petrol or diesel car, so they are suitable for everyone. If you switch to a mild hybrid, you will likely see a slight improvement in your operating costs, but little to no difference in your driving experience.

There are many quality used hybrid cars to choose from at Cazoo and now you can get a new or used car with Kazu's subscription. Just use the search feature to find what you like and then buy, fund or subscribe to it online. You can order delivery to your door or pick up in the nearest Cazoo Customer Service Center.

We are constantly updating and expanding our range. If you're looking to buy a used car and can't find the right one today, it's easy set up promotional alerts to be the first to know when we have vehicles that suit your needs.