Fuel Type Guide

Petrol has long been the middle-of-the-road, standard option, and is still a popular alternative to diesel and electric for car owners. There are three common types in the UK:

If you’ve got a petrol fuel car sitting in the drive-way, there’s a high chance that you’re using premium unleaded fuel. The ‘premium’ in its title comes from a higher-than-average octane rating. Despite this name, it’s still the most commonly used fuel-type in the UK and compatible with almost all petrol engines.

Super unleaded is a petrol fuel that comes with a higher octane rating – usually 97/98 is common to see at the fuel pump. The octane rating determines just how ignitable the fuel is. The higher this rating is, the more resistant to ignition the fuel is when under pressure – which is, of course, a good thing. This fuel is mostly used with high-performance vehicles that require that extra resistance.

Premium fuels are, in theory, the most efficient and should offer the best value. This is because they have the highest octane rating of any petrol fuel. Naturally, the benefits of premium fuels depends on how often you drive your car and the distance you drive it. Only with frequent travel over long distances will you truly gain from its incremental difference to unleaded petrol.

While everything else has adapted to the rising tide of green energy, diesel fuel has struggled to compete – despite its performance benefits. But there are still a few options to consider when choosing the best diesel fuel. In the UK, there are three types of diesel to choose from:

Usually, you will only find one diesel pump at the station – it’s normally black, marked as diesel and will work with any diesel vehicle. Should you come across a label that says low-sulphur or city diesel, then it’s important to know that the main difference between them lies in their sulphur levels. The lower the sulphur level in the diesel, the less harmful it is to the environment – though the sulphur is needed to lubricate your car’s engine and retain its performance levels. So while less sulphur is more eco-friendly, it’s not always great for your car. This issue is part of the reason why diesel has struggled to adapt to the growing demand for eco-friendly fuels.

Similar to premium petrol, premium diesel offers generally better fuel economy and better performance. But instead of octane, look out for cetane with diesel engines. The higher the cetane rating, the more efficiently it will burn fuel and perform at a higher level for a longer period.

Cleaner and cheaper than petrol, liquified petroleum gas (LPG) is a combination of propane and butane gas and available at most UK fuelling stations. The most important benefits of LPG are that it produces a lower rate of harmful emissions can can be more cost effective. However, it’s worth noting you may not get as many miles to the gallon with LPG as you do with regular petrol. Petrol engines can be converted to run on LPG and the process of conversion is relatively inexpensive. But the differences are incremental and the benefits will depend on whether you’re a frequent road user or not.

Eco-friendly regulations are testing fuel suppliers’ creativity, and biofuel is an excellent example of more efficient, greener solution. It’s likely that your car will need to be modified to run on these types of fuel, so double-check to see if your vehicle is compatible before making the switch. There two main types of biofuels are:

A plant-based fuel that’s produced by the fermentation of wheat, sugar cane sugars and other plant material. It can be ethanol-free and used on its own, or blended with petrol as ethanol fuel.

Similarly to bioethanol, biodiesel is plant-based, but made from rapeseed oil and other plant-based oils. It can also be used on its own, or blended with diesel.

As more cars step away from traditional fuel-focused options, the hybrid phenomenon continues to grow in popularity. Hybrid cars run on two or more different power sources working simultaneously to propel your car – petrol or diesel combined with an electric motor. There are three main types of hybrid available to you in the UK:

PHEVs have become more common in recent years, most likely to due to their diverse capabilities and improved electric-only range. They can be driven on fully electric power as well as switched over to petrol or diesel power as needed. PHEVs also boast the ability to ‘self-charge’ – using the car’s braking power to recharge the electric motor, a common practice in hybrid vehicles. When you’re not driving, you also have the added benefit of being able to plug your car in to charge its battery – an option available only on plug-in hybrids.

Unlike PHEVs, the electric motor plays more of a supporting role here, while the petrol or diesel engine does the main work. The difference between the two is a matter of degrees: in full hybrids, the electric motor plays more of a role in powering the car than in mild hybrids. The electric motor in a full hybrid can take over powering the car at certain speeds and will combine with the combustion engine to increase performance and power at high speeds. In a mild hybrid, the electric motor may simply help out with accelerating.

Full and mild hybrids are only self-charging and cannot be plugged in. Self-charging is a slightly fancy branding name given to the process. Essentially, when the car isn’t accelerating, it requires less power to function. The electric motor transfers this unused energy to its battery, effectively recharging it while driving. Different models use different processes to help charge the battery, such as using energy from the brakes. For this reason, manufacturer’s refer to this feature as ‘self-charging’ – which also sounds better than saying you can’t plug it in while you’re at home (the main difference to PHEVs).

We’ve saved the greenest to last – if being eco-friendly is a priority then the full-electric options are for you. Recent innovations mean that EV performance is just as reliable as petrol or diesel performance these days. Electric vehicles use a battery-powered motor that can be plugged in and recharged. Charging is a little more demanding, and can take a minimum of several hours – which in the past, would’ve required more planning. However, there are now more charging-stations popping up across the UK in accessible locations like supermarkets and public car parks, so this is no longer so much of an issue. The range these cars can travel before needing a recharge has increased too – the popular Nissan Leaf Plus manages 226 miles, while the Tesla Model Y can top 310.

The rapid growth in popularity of eco-friendly cars, as well as pressure on manufacturers to deliver green vehicles, has led to the development of innovative fuel types. A lot of these options are still being developed, so it’s important to research them before making a permanent switch. Armed with the right information, like this handy fuel type guide, you can make the best choice for your needs.