Choosing the Right Fuel Type for You

Still the most common way for drivers to power their car, petrol isn’t going away anytime soon, although it has dwindled in popularity a little in recent years. It’s burned as part of a car’s internal combustion engine, and the energy produced is used to move your car. It’s readily available from petrol stations all over the world, where you can pump it into your car quickly and easily.

Probably the main advantage that petrol has over other fuel options is its price. Petrol is cheaper to buy than diesel, and when manufacturers produce a particular model with a variety of engine options, the petrol unit tends to be the most affordable. Buyers with a limited budget will, in most cases, opt for a petrol engine.

On the other side of the coin, the savings that you make when using a petrol engine will be reduced significantly if you’re driving a lot or driving over long distances. This is because petrol has a much lower efficiency than other types of fuel, and you’ll get more miles to the gallon with a diesel engine. A typical example is the most recent VW Golf. The German manufacturer claims that its petrol engine can achieve around 50 miles to the gallon, which is a very respectable figure for a petrol unit. But when you compare this to an advertised figure of over 60 mpg for the diesel engine and over 200 mpg for its plug-in hybrid powertrain, you’ll see that the petrol engine might not be the most cost-effective option in the long term. Take a look at our list of ten of the best petrol cars with great MPG to check out the most fuel-efficient petrol cars.

Another drawback of the petrol engine is its harmful impact on the environment. The burning of petrol and other fossil fuels releases huge amounts of CO2 into the atmosphere, contributing towards air pollution and climate change. Sourcing and processing these fuels also does a lot of damage to the planet. If you’re someone who cares about sustainability and driving in an eco-friendly way, you’ll want to make sure you find a petrol engine with the lowest emissions figures possible – or more likely opt for an alternative fuel type.

Diesel is another popular fuel choice, though it’s unclear what the future of diesel engines has in store. Though a number of models are being produced with new diesel units available alongside their petrol equivalents, diesel engines have been largely discontinued in the UK by some leading manufacturers, including Renault and Honda.

Diesel has always been a popular fuel choice for larger vehicles, such as lorries and buses. This is partly down to the increased torque that diesel engines can provide. Diesel also contains more energy per gallon than petrol, so it’s a more efficient fuel, particularly for motorway driving with fewer stops and starts. This made it the go-to engine option for drivers who regularly travel long distances for commercial reasons. The key difference between a petrol and diesel engine is that the latter doesn’t have spark plugs, and generates heat using more extreme compression. This also means that a diesel engine has fewer parts, and is cheaper and simpler to maintain as a result.

Diesel is often slightly more expensive than petrol, and cars with diesel engines usually involve a greater initial outlay. But if you’re planning to put some serious mileage on the clock, a diesel unit might be the best choice for long-term savings. We’ve put together a list of ten of the best diesel cars to help you choose which one is right for you.

Diesel has always had a bit more of a problem with putting out soot and harmful gases than petrol, but advancements in technology such as diesel particulate filters and AdBlue cleaned up these emissions somewhat. For years, this satisfied motorists and governments that diesel was a clean enough option, and perhaps even a superior choice to petrol due to its efficiency.

That positive perception changed with the emissions scandal of 2015, and diesel sales since have tumbled. While the current Euro 6 standards (and even tighter incoming EU7 standards) ensure new diesels are a relatively clean choice, the damage to diesel’s reputation has possibly already been done. Cars that don’t meet these standards can be subject to higher congestion charges, higher tax and even further restrictions in some cities around Europe, with more similar legislation being proposed all the time.

With this comes speculation that diesels on the used market won’t be able to hold their value well, whether they meet the higher standards or not.

That said, a lot of the major changes headed our way over the coming years and decades target all internal combustion engine cars – both petrol and diesel – as part of a push towards an all-electric future with no emissions. Most notably, the UK government has announced it will ban the sale of new internal combustion engine cars from 2030. So, while the future of diesel doesn’t look particularly bright, it’s likely no different for petrol.

If you’re looking for a forward-thinking option, hybrid and all-electric might be the way to go.

Since the Toyota Prius first introduced the mass-market to electric power back in 1997, hybrid cars have become a hugely important new breakthrough for the automotive industry. It’s now becoming the norm for newer models to have at least one petrol-hybrid or diesel-hybrid engine available for buyers.

There are two main types of hybrid engines. A mild hybrid combines a regular petrol or diesel engine with a backup electric motor. When extra power is needed to turn the wheels, the electric engine uses its stored energy to provide support. That engine is run not off fuel, but off a battery, which is charged up by the regular fuel engine when it’s not needed to power the wheels – like when it’s coasting or cruising. The use of electric power means that this conventional engine can also be turned off entirely in certain situations, for instance when the car is stopped at traffic lights or travelling downhill. You can also find full hybrid cars, which are similar to a mild hybrid but with a larger battery, sometimes offering electric power assistance to the engine in more situations.

A plug-in hybrid (PHEV) is a more advanced version of this concept, with an electric engine that can run independently of the petrol/diesel unit. You can charge its battery using an external mains power supply, and it has enough juice to power the car entirely on its own.

Switching between electric and diesel/petrol power means that a hybrid car gets more miles to the gallon than a regular petrol or diesel one. The mild hybrid electric engine can’t run the car completely on its own, so the difference isn’t always hugely significant, but it’s definitely noticeable. With a PHEV or full hybrid, you’ll see some unprecedented efficiency figures, often up to four times better than a conventional engine. The huge fuel savings make a plug-in or full hybrid particularly appealing to those who might have looked to a diesel in the past.

Probably the most obvious benefit of hybrid power is its reduced impact on the environment. Carbon emissions are significantly lower for hybrids, with even the most basic mild hybrid powertrains offering figures well below 100 g/km, compared to around 120 g/km for the cleanest petrol or diesel engines. As well as allowing you to drive in a more sustainable way and contribute to a better future, these lower emissions can also get you major discounts on your road tax in the UK – up to 100%.

One note of caution. While the plugin-hybrid might still look like a future-forward engine to some, it might not actually be around for as long as you think. The UK government’s announcement on the banning of new combustion engine car sales from 2030 came with a second announcement: a similar ban on the sale of new plug-in hybrid cars from 2035. That said, this change is still a fair way off, and with the above benefits in mind, plug-in hybrids are likely to be a desirable option for a good while yet.

View our list of ten of the best hybrid cars available to buy to see if one’s right for you.

Relatively speaking, all-electric cars are still in their infancy, but advancements in electric motor tech and performance are making them more and more common on UK roads. Some models have already made a name for themselves – the Nissan Leaf is now well over a decade old, and it’s one of the models leading the way in terms of pure EV cars that are within the price range of the average buyer.

An EV car has no petrol or diesel unit whatsoever and its engine runs entirely on electricity. Instead of filling up with petrol or diesel, you’ll need to recharge your battery, either at a public charging point or at home. It’s possible to just plug in your car to the mains, but most vendors will recommend that you install a special charging point with a higher voltage to cut down on recharge times.

The eco-friendly and cost-cutting benefits of EV vehicles are obvious, and they’re increasingly rivalling the top petrol and diesel-powered cars for performance and reliability. Go electric and you’ll be reducing your contribution to climate change and also cutting down on noise pollution with the engine’s whisper-quiet road presence – all that without sacrificing speed or driving satisfaction. You’ll also probably find that your slightly higher electricity bills will be hugely outweighed by having zero fuel costs. Plus, you might even be able to get money towards paying for a charging point at home or at your work, depending on where you live. Why not take a look at our list of the best electric cars on the market to see if any catch your eye.

However, there are a few obvious drawbacks with this still-emerging technology. Charging your battery is, as it stands, a lot less convenient than filling up with petrol or diesel. Charging points aren’t always conveniently located and at-home charging can sometimes take up to 20 hours. There are also issues with the driving range of electric vehicles. Even the best-in-class EV cars can’t achieve more than 300 miles on a fully-charged battery, and an average figure is closer to 150 miles. Compare this with a petrol or diesel car, which can travel up to 400 miles on a full tank and you’ll see the main downside to this type of engine.

Now you know the basics of the different fuel types, you’re in a better position to choose your next car. So it’s time for you to decide what your main priorities are. Do you want to pay as little as possible now, or make savings in the long term? Do you want to protect the planet, or do you need convenience above all else? To learn more, take a look at our advice guides and in-depth reviews covering the best petrol, diesel, hybrid and electric cars on the market.