What is B7 diesel?
B7 diesel is the standard grade you’ll find at most UK forecourts. It contains up to 7% biodiesel, made from used cooking oils and animal fats. This blend helps reduce carbon emissions compared to pure petroleum diesel.
The 7% biodiesel content affects how the fuel behaves. It may affect engine performance in older vehicles and require proper storage to avoid issues. Most modern cars handle B7 fine, but older models might need a switch to lower blends during cold weather. Many older vehicles may struggle with B7 in cold weather.
B7 is also more corrosive than traditional diesel. Additives like anti-wear agents help mitigate this, but some older fuel systems lack the necessary components to handle the blend. That’s why you’ll see warnings on some older car manuals advising against using anything above B5.
What’s in premium diesel?
Premium diesel includes additives like detergents and corrosion inhibitors. These claim to clean fuel injectors, reduce carbon build-up and protect engine components. Some brands add more than others, but the difference is rarely visible in real-world driving.
Is it worth it? For most drivers, no. Unless your car is under warranty and the manufacturer specifies premium, the extra cost isn’t justified. Many drivers do not notice significant benefits from using it. Even when used, the additives in premium diesel don’t significantly improve fuel economy or engine longevity.
Manufacturers often push premium as a ‘premium experience’, but the science doesn’t back it up. In lab tests, the difference between premium and standard diesel is negligible. The main savings come from using it in high-mileage commercial vehicles, where injectors might benefit from regular cleaning.
Where is diesel heading?
B10, with 10% biodiesel, is becoming more common. It’s a step towards lower emissions but carries the same risks as B7. Some fleets use it, but it’s not yet widespread for private vehicles.
HVO, or hydrotreated vegetable oil, is the future. It’s made from plant oils and waste materials, and it burns cleaner than B7. A few forecourts in the UK now sell HVO, though it’s pricey. It’s compatible with all diesel engines and doesn’t require engine modifications.
HVO is a major development. Unlike B7, it doesn’t produce particulate matter or nitrogen oxides. HVO production is increasing, though it remains limited in availability.
The price question
Premium diesel is typically more expensive than B7, though the exact difference varies by location. Use the compare fuel prices tool to see local differences. Some areas have bigger gaps than others. In London, for example, premium diesel is often more expensive than B7, while in rural areas the gap is smaller.
HVO is even pricier. At 169.4p, HVO costs around the same as other premium fuels. That’s a significant premium. The higher price of HVO is due to both production costs and limited supply. Only a small number of UK forecourts currently sell HVO.
The environmental angle
B7 and B10 are part of the UK’s strategy to cut emissions. The biodiesel in B7 helps reduce emissions compared to pure diesel. But the real challenge is scaling up to higher blends without damaging older engines.
HVO is a cleaner alternative. It’s made from waste materials, so it doesn’t compete with food crops like traditional biodiesel. It also has a lower carbon footprint than fossil diesel.
Yet adoption is slow. HVO is more expensive and less widely available than B7.
Common questions
What’s the difference between B7 and B10?
B10 has 10% biodiesel instead of 7%. It’s slightly cleaner but carries the same risks for older engines.
Is premium diesel better for my car?
Only if your manufacturer specifies it. For most cars, standard diesel works fine.
What is HVO and why is it important?
HVO is a renewable diesel made from plant oils. It’s cleaner and compatible with all diesel engines, but it’s expensive.
How much more does premium diesel cost?
Typically more expensive than B7, though the exact difference varies by location. Use the prices by brand page to check local rates.
Are there any benefits to using HVO?
Yes. It reduces emissions and doesn’t require engine modifications. But it’s not yet widely available.