Fuel Types

This guide is designed to help you understand the differences between each of the four main fuel types: petrol, diesel, hybrids and electric. As part of this, we will compare the costs and benefits of each of these fuel types.

For a more detailed understanding of these fuel types then you might want to look at our dedicated petrol, diesel, hybrids, and electric vehicles (EVs) guides.

What is Traditional Fuel?

A traditional combustion engine will run on one of two fuels, either petrol or diesel. The engine burns fossil fuel in order to power the vehicle, which is why your fuel consumption will increase when you need a lot of power, for example when accelerating or travelling uphill.

One thing to be aware of if you are looking at funding the vehicle yourself is that there are several restrictions and penalties that you might see for vehicles with a traditional combustion engine through the introduction of low emission zones as the government push drivers towards EVs options and individual towns and cities look to improve their air quality through vehicle restrictions.

Petrol

Petrol was the original fuel for combustion engines and remains on our roads as one of the most popular options for first time and long-time drivers alike. A large part of petrol’s longevity, especially with alternatives now available, is the great benefits that it gives drivers.

What Types of Petrol are There?

Petrol that we use in cars in unleaded but you might also see premium unleaded or super unleaded at the pumps. This premium fuel contains a higher octane content, which is measured by its Research Octane Number (RON), the higher RON means that the fuel will burn at a slightly higher temperature which means the engine gets more power.

When standard petrol changed to the higher ethanol content of E10, which allows up to 10% ethanol in the mix super and premium unleaded remained at E5. E5 has better fuel efficiency so will allow you to travel more miles on the same amount of fuel. 

Benefits of Petrol

Petrol is the most common fuel type available in the UK and so there is the widest range of models within this fuel type, from superminis and coupes to seven seat SUVs there’s a petrol car for every driver.

You will usually find that petrol vehicles are the cheapest, both in terms of initial cost, whether purchasing or leasing, and its running costs.

In terms of running costs, petrol is cheaper at the pump than diesel, the maintenance costs will usually be lower because they do not have the same electronics that a hybrid or EV has, or the specialist diesel equipment.

Of the two traditional fuel types petrol has the lowest overall emissions compared to diesel so will not have as high emission-based taxes, like road tax.

Drawbacks of Petrol

There’s a reason that cars using a traditional engine are being banned, which is that they are bad for the environment due to their use of fossil fuels.

It’s not only the use but also the production and transportation of petrol and diesel that pollutes the environment with toxic emissions.

Though petrol has fewer overall emissions the level of CO2 emissions they emit compared to a similar diesel model is higher. So, if you are looking for a company vehicle you should bear this in mind as the BIK rate will be higher on a petrol model, due to part of the calculation being based on CO2.

Another thing to be aware of is that as of 2030 the sale of new petrol models will be banned, along with the sale of new diesel and hybrid vehicles. Over the years following this you will see repairs and parts becoming more difficult to find and costly.

Diesel

The second traditional fuel we mentioned was diesel. Though there have been varying opinions on whether it is better or not than petrol there are a number of benefits that still make it a strong choice.

What Types of Diesel are There?

Most fuel stations will usually only have one type of diesel fuel available however there are some that will offer other types of fuel.

You might see city diesel or low-sulphur diesel on offer which is a diesel that has a lower sulphur content so is more environmentally friendly as it does not emit as much sulphur dioxide or fine particle matter. It also helps extend the life of your engine.

Additionally, some providers will offer you premium diesel which has a higher certane number, additional chemicals to help keep the engine clean and better lubricity.

Benefits of Diesel

Diesel engines are typically larger and more powerful, which gives you greater torque for faster overtaking and better towing power.

Typically diesel will offer drivers better fuel economy than petrol, so although it costs more per litre at the pump you can usually make your money run a little further on the road.

We mentioned above that petrol vehicles have higher CO2 levels, which means that diesel cars actually have lower CO2 emissions when comparing two similar models. Lower CO2 emissions also mean a lower BIK tax for drivers who are choosing a new company car.

In general diesel models are cheaper than electric or hybrid versions of similar style and spec levels, whether you are looking to purchase or buy your next model. If you are looking at a company vehicle and your business has a structure where you are only allowed models of a certain price bracket then you’ll be able to get more with a diesel.

Drawbacks of Diesel

Though there are many benefits with diesel vehicles there are also some considerations you need to make.

The first is that although diesel cars have lower CO2 levels their overall emissions are much higher than any other fuel type. In fact, they are so high that they need to be fitted with a diesel particulate filter (DPF) which helps filter out some of the most harmful emissions. This filter requires a particular driving style and is not suited for consistent low-speed urban driving.

If you do not drive regularly on high-speed moving roads then the filter might become clogged and need replacing which can be expensive. You might also find that as there are more parts like the DPF that maintenance prices might be more expensive than for a petrol vehicle.

The cost of diesel is higher than petrol so the cost of filling your tank up will be higher than if you have a petrol car. However, as mentioned above you can usually get better fuel economy from diesel.

Diesel cars have a higher road tax so if you are responsible for paying this then you will need to factor into your budget the cost of paying this.

What Happens If I Put the Wrong Fuel in My Vehicle?

If you put the wrong fuel in your vehicle it's important that you do not turn on the engine as this will push the fuel through the engine and cause further costly damage. If you've already started the engine you should turn it off as soon as you are able to. 

You should then call a professional to come and remove the fuel from your tank and clean the engine if required. 

Hybrid Vehicles

Benefits of Hybrids

As hybrids have both a traditional combustion engine as well as an electric motor they have some of the benefits and drawbacks of both of these as well as their own unique ones.

Many drivers, and businesses trying to encourage their drivers to go electric, see a hybrid model as a stepping stone in the electrification journey. They can give you some of the benefits without the major concerns the people have with an EV.

You will not need to worry about running out of charge on a hybrid as when the battery is depleted the vehicle will switch over to the combustion engine. This will be the case even with a PHEV, though we do recommend regularly charging them so you can actually utilise the electric motor.

PHEVs and the majority of HEVs will offer a fully electric range which means that you will benefit from some of the incentives that the government have in place for greener drivers, like a lower BIK rate.

Hybrids emit fewer emissions than a petrol or diesel car and so they are less harmful to the environment, produce less air and noise pollution. Lower emissions also mean that the road tax will be lower for you if it is your responsibility.

Drawbacks of Hybrids

If you opt for a PHEV then you will need to plug the vehicle in to charge it in order to make the most of the electric motor.

As a hybrid vehicle has both a combustion engine and an electric motor with a battery to power it you will likely find that this has had an impact on the car’s passenger and cargo space.

It will also have an effect on the cost when it comes to servicing and maintenance work. This is because there are two systems for work to be completed on.

Some hybrids, like those using mild-hybrid technology, will not have a purely electric range, the hybrid components instead kicking in when the combustion engine needs a boost of extra power.

You will also find that even the hybrids that do have a purely electric range will only have a short one compared to an EV. If you are wanting a larger range then it will be PHEVs that you want to look at, as they have a larger battery due to it being recharged by an external power source.

Electric Vehicles

An EV is one that is purely powered by a rechargeable battery and electric motor.

We mentioned above that the sale of new petrol, diesel and hybrid vehicles will be banned in the UK from 2030, which means that going forward from then the main option for drivers will be EVs. There are alternative fuel sources being developed, like hydrogen cells, but most manufacturers are focused on EV development for their mainstream products.

Benefits of Electric Vehicles

Electric vehicles come with a whole host of benefits and the most noticeable is the fact that they produce zero emissions when running. This will improve the air quality where you are driving, reduce your carbon footprint, both personally and for your business if you have a company car, and help reduce pollution in your area.

Depending on your energy provider there may be some emissions produced in manufacturing and storing the electricity that you then use to power your vehicle, however this will be less than the amount needed to extract, transport and use the fossil fuel that combustion engines require.

As there is no combustion engine EVs are much quieter than a traditional vehicle. In fact, they’re so silent that many companies have added an option for noise to help make other road users aware of their presence.

As they have zero emissions when in use the BIK rate of an EV is incredibly low compared to other options. Currently it is at 1% and will rise to 2% for the 2022/23 tax year, which is a great incentive if you’re looking at options for your company car.

If you are looking to fund the vehicle yourself then there are government grants available to help with the purchase price of EVs. For drivers considering a lease, this saving will be taken into account for you and will aid in giving you the best lease deals.

There are also grants available to help with the cost of installing a charger, both at home and business addresses.

In general, because they have fewer parts EVs will require less maintenance work than those with combustion engines.

Drawbacks of Electric Vehicles

There are two main concerns that we regularly see drivers express over driving an EV: charging and mileage range.

Many people worry that the mileage range will not be enough for their needs, however they’re often thinking larger than they need to. Most drivers will be able to charge the vehicle overnight at home or during the day at their place of employment and so you really need to break your mileage needs down to your daily need.

We recommend all drivers ask themselves ‘how far do I drive each day?’ and then seeing how that looks compared to the EV’s range.

There will be occasions when you need to travel further than the range on a vehicle and in these cases you will need to plan your journey around convenient charging stops, as well as factor in the charging time to your overall journey time.   

Due to the technology involved in them, EVs tend to have a higher purchase price which is why the government’s grant can be a helpful incentive and makes them more affordable for individual drivers.

Because of this technology, the maintenance costs when they do need work will be higher as they require specialist equipment, more expensive components and specially trained mechanics.

Deciding the Right Fuel Type for You

We hope this guide has been useful for you in looking at the pros and cons of each of the four common fuel types on UK roads and deciding which would be the best option for you.

The table below shows which we think is the best choice for each of the considerations listed.

Choosing the right fuel type is only part of the equation when deciding on the right car for you. We’ve got a more detailed breakdown here of all the other factors you want to take into account when looking for your next car.

If you want to find out more about the types of vehicle fuel available, making the most of your fuel and much more then head back to our helpful guides.