Fuels FAQ – Learn the What, Who & Why

Gas Oil – The What, Who & Why of Fuels

which gas oil
Are you wondering what the difference between gas oil and red diesel fuel is?

With so many different types of fuel available nowadays, it can be hard to know which is the correct choice for your vehicle or machinery.

From diesel fuel to kerosene, there are many different types of fuel available nowadays. In this article, we explain what you can use each type for, who uses it and why.

There are two main types of diesel called gas oil and road diesel. They are virtually the same thing except that a coloured dye gets added to gas oil for industrial purposes.

What is gas oil?

It is a type of fuel oil distilled from petroleum and heavier than paraffin oil. It is cheaper than normal road diesel as it is a rebated fuel.

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What about red diesel?

[schema type=”product” name=”Red Diesel” description=”Aka. gas oil, is a heavy oil which carries a lower (rebated) rate of duty. It is also commonly known as ’red’, ’red diesel’ (because of the red dye) or ’marine gas oil’.” condition=”New” ]

Red diesel is similar to white diesel with only one important difference – it contains a red dye to make it distinguishable from authorities such as the police or VOSA (Vehicle and Operator Services Agency) who may need to inspect it.

Red diesel has a rebated tax associated with it as you can only use it as a non-road user. You may hear it being called “gas oil”, “tractor diesel”, “heating oil”, “generator fuel” and “digger fuel.” Although the red dye can be removed from red diesel, this is not a legal process and could result in a hefty fine or even a prison sentence being given to you.  This is because it is subject to lower taxes than diesel / derv. You are only meant to use it in certain types of machinery or vehicles used in certain industries such as within agriculture or construction.

There are some exceptions for using red diesel on the roads, although these are usually in rare, limited occurrences. If you absolutely need to use it in a vehicle on the public roads, you must get a license from the HMRC. However, this is only for exceptional circumstances. This is where it would unnecessarily cause an obstruction for someone to have to take the necessary steps to avoid using rebated heavy oil on the public road. If you are unsure about the law, you can find out more information from the HMRC website.

[schema type=”product” name=”Diesel / Derv” description=”Diesel (or diesel engined road vehicle) is a fuel which you can use to power vehicles with diesel engines.” condition=”New” ]

You might sometimes hear diesel or derv being called “taxed diesel”, “road diesel” or a “regular pump diesel.” Derv is a liquid fuel product which you can use for transport and passenger vehicles. You can use it most commonly in cars and lorries which have diesel engines, for vehicles used on the roads and some other equipment.

As well as these products, there are other types of fuels to discover:

What is kerosene?

[schema type=”product” name=”Kerosene / Heating Oil” description=”Kerosene is the perfect heating fuel for all types of commercial and domestic premises.” condition=”New” ]

You can store kerosene in a blue or blue-labelled barrel so you don’t mix it up with other fuels. You can also keep it in a drum or container. You can use it to power both industrial, commercial engines, some machinery, and domestic heating systems. Some people know it as “paraffin” or “heating oil.” Like gas oil, Kerosene contains a chemical marker to distinguish it from other fuels.

Who uses these fuels?

If you use construction machinery or agricultural machinery, then you are more likely to need gas oil (red diesel). You can also use it in commercial equipment such as bulldozers, generators, tractors, cranes, bobcats and combine harvesters.

If you need to use fuel for lamps or lighting fuels, fire entertainment or even for jet engines, then you will more likely need to use Kerosene.

As well as red diesel / gas oil, white diesel / derv and kerosene, we have a range of additional fuels and lubricants at Crown Oil. From Carbon Offset fuel to CHP biofuel and AdBlue, to help reduce NOx emissions and comply with existing laws, there are plenty of fuels available to choose from.

Why use the right fuel?

It is important to use the right fuel for your machinery or equipment to avoid causing unnecessary problems associated with the overall performance. Using the wrong type may lead to blocked filters, a sludge build-up within the tanks or even water intrusion.

Want more advice?

Here at Crown Oil we have the answers with almost 70 years’ experience in the industry. We can advise you on your red diesel, diesel/derv, and heating oil requirements. Give our friendly, knowledgeable fuels specialists team a call on 0845 313 0845. They will be happy to assist you with your unique requirements and provide you with the best solutions.

If you want further information about gas oil, diesel/derv or kerosene, please find the following fact sheets available below:

Gas Oil

Kerosene factsheet

diesel / derv






You can also learn more about which fuel you can use in road vehicles via the following link:

From a technical perspective, the sulphur is the main difference between Gas Oil (0.1%) and Diesel (0.001%).