What Is HVO Fuel? A Complete Guide for UK Homes, Farms & Businesses

If you’ve been paying attention to the energy, construction, or transport sectors over the last few years, you’ve probably heard the acronym “HVO” thrown around. It’s often marketed as a miracle fuel—a “green diesel” that can instantly wipe out the majority of a business’s carbon footprint without requiring new machinery.

But what exactly is it? How is it made? And is it truly the silver bullet for the UK’s transition away from fossil fuels?

Whether you’re a homeowner looking to green up your off-grid heating, a farmer trying to reduce emissions on your tractors, or a logistics manager navigating Clean Air Zones, this guide breaks down everything you need to know about Hydrotreated Vegetable Oil (HVO).

Let’s lift the lid on the fuel that’s quietly transforming how the UK runs.

What Is HVO Fuel?

HVO stands for Hydrotreated Vegetable Oil. Despite the name, it isn’t exclusively made from vegetables anymore. It is a premium, 100% renewable, synthetic diesel alternative.

Unlike traditional fossil fuel diesel, which is derived from the earth and is a by-product of crude oil, HVO fuel is made from environmentally friendly sources of waste. Most importantly, it is classified as a “drop-in” fuel in industrial language. In other words, its chemical composition is basically identical to that of standard mineral diesel. It can be simply poured into any modern diesel engine without the need for any changes to the equipment.

It is completely colourless and odourless, earning it the nickname “green diesel” (due to its environmental credentials, not its physical appearance).

How Is It Produced? The Hydrotreatment Process

The magic of HVO lies in how it’s made. While older, first-generation biodiesels (often called FAME) were created using a simple chemical reaction called transesterification, HVO undergoes a highly advanced, multi-step refinery process.

1. Sourcing the Feedstock: The raw materials usually consist of verified waste products. This includes Used Cooking Oil (UCO) collected from restaurants, waste animal fats (tallow), and sometimes tall oil (a residue from the wood pulp industry).
2. Pre-treatment: The waste oils are heavily filtered and cleaned to remove impurities.
3. Hydrotreatment and Isomerisation: This is the core step. The cleaned oils are subjected to high temperatures and pressures in the presence of hydrogen. The hydrogen strips out all the oxygen from the oils and converts them into pure, paraffinic hydrocarbons.
4. The Result: Because the oxygen has been entirely removed, the final product is an incredibly pure, stable, and clean-burning fuel that mirrors the exact structure of standard diesel—just without the environmental baggage.

HVO vs Fossil Diesel: What’s the Difference?

While they might run the same engines, HVO and standard fossil diesel (often called DERV or white diesel) are worlds apart when you look under the microscope.

Here is a breakdown of why HVO often outperforms its fossil counterpart:

• Cetane Number (Combustion Quality): The cetane number of fossil diesel is usually about 51 while HVO has a cetane number of 70 to 90. It indicates that HVO ignites very quickly and effectively; hence, it gives an easy starting and less engine noise.
• Purity: Fossil diesel contains sulphur, aromatics, and metals that cause soot build-up in engines. HVO is a pure paraffinic hydrocarbon, meaning it burns incredibly cleanly.
• Cold Weather Performance: Standard diesel can “wax” or gel in freezing temperatures, clogging fuel filters. HVO has excellent cold-weather properties, with a freezing point extending well below -30°C, making it ultra-reliable in harsh British winters.

Applications Across the UK: Who is Using HVO?

Because it requires zero infrastructure changes, HVO is rapidly infiltrating multiple sectors across the UK as a fast-track solution to Net Zero targets.

1. Homes (Off-Grid Heating)

For the millions of UK homes located off the national gas grid, heating is usually provided by kerosene or gas oil boilers. HVO is stepping in as a direct drop-in replacement for domestic heating oil. While older boilers might need a minor, inexpensive nozzle or pump adjustment by a technician, making the switch instantly reduces household heating emissions by up to 90%.

2. Farms and Agriculture

There are many agricultural vehicles that run on diesel, including tractors, combine harvesters, and water pumps. By using HVO (“red HVO,” which includes the rebated duty dye), farmers can significantly decrease the carbon footprint of their crops. Since fuel is stored in bulk by farmers, the long shelf life of HVO becomes a huge benefit over conventional diesel.

3. Businesses, Haulage, and Construction

For the logistics fleet and HGVs, electric power is too bulky and offers limited range to operate on long distances. HVO helps reduce emissions without any delay caused by the development of electrical truck infrastructure.

Similarly, construction sites—which lost their right to use cheap red diesel in 2022—are increasingly specifying HVO to power their excavators and site generators, helping them meet strict corporate ESG targets and comply with urban Clean Air Zones.

Compatibility and Storage: The Death of the “Diesel Bug”

One of the biggest headaches with storing standard fossil diesel (and particularly first-generation FAME biodiesel) is the “diesel bug.” Because FAME absorbs water from the air, it creates a breeding ground for microbial bacteria in storage tanks, leading to sludgy fuel that blocks engine filters. Mineral diesel generally has a reliable shelf life of only about 12 months.

HVO eliminates this problem. Because the hydrotreatment process strips out all oxygen, HVO does not attract water. It is highly resistant to oxidation and bacterial growth.

• Shelf Life: You can store HVO safely for up to 10 years without it degrading. This makes it the ultimate choice for data centres, hospitals, and businesses that rely on standby backup generators that may sit unused for years.
• Mixing: You don’t even need to clean out your old tank. HVO can be mixed freely with whatever fossil diesel is left in your storage tank or vehicle.

Emissions Considerations: Is It Really “Green”?

It’s important to clarify that HVO is not a zero-emission fuel at the tailpipe. When you burn it, CO2 still comes out of the exhaust. So why is it considered sustainable?

It comes down to the lifecycle emissions. The carbon released by burning HVO is the same carbon that the plants (or the animals that ate the plants) absorbed from the atmosphere while they were growing just a few years ago. It is a closed carbon loop. Fossil diesel, conversely, pulls ancient carbon from deep underground and pumps it into the modern atmosphere, adding new carbon to the environment.

Across its full lifecycle, HVO reduces net Greenhouse Gas (GHG) emissions by 89% to 90%.

Furthermore, because it lacks the impurities of crude oil, it drastically improves local air quality by reducing tailpipe pollutants:

• Up to 30% reduction in Nitrogen Oxides (NOx).
• Up to 80% reduction in Particulate Matter (PM / soot).

Benefits and Limitations Summary

The Benefits:

• Immediate Impact: A 90% carbon reduction achievable today, without buying new fleets.
• Drop-In Ready: Zero modifications required for modern diesel engines (EN 15940 compliant).
• Engine Health: Cleaner burning means fewer blocked DPFs (Diesel Particulate Filters) and less maintenance downtime.
• Storage King: Up to a 10-year shelf life with zero risk of the diesel bug.

The Limitations:

• The Cost Premium: The advanced refining process means HVO currently costs more per litre than standard fossil diesel.
• Not Zero-Tailpipe: This is a transitional fuel and not a permanent solution like wind, solar, or green hydrogen.
• Supply Scalability: Even though supply has been increasing at a rapid rate in the UK, the feedstock of used cooking oil and fat is limited to finite global supplies.

Frequently Asked Questions (FAQs)

1. Do I need to clean my tank before switching to HVO?

No. HVO is fully miscible with fossil diesel. You can simply top up your existing tank with HVO. As you continue to refill with HVO over time, the concentration of fossil diesel will naturally dilute until you are running on pure renewable fuel.

2. Will using HVO void my vehicle’s warranty?

For the vast majority of modern vehicles, no. HVO meets the EN 15940 standard for paraffinic diesel. Most major heavy-duty OEMs (Original Equipment Manufacturers) like Volvo, Scania, and Caterpillar, as well as passenger car brands like Peugeot and Ford, officially approve its use. Look for the “XTL” sticker inside your fuel cap. However, always check your specific manufacturer handbook if you are unsure.

3. Is HVO made from palm oil?

This is a very valid question. In the past, there have been cases where biofuels were responsible for deforestation because of palm oil plantation purposes. However, today’s good and trusted UK HVO suppliers ensure that their HVO is 100% palm oil-free and only comes from verified waste products such as used cooking oil.

4. Can I use HVO in cold British winters?

Yes, indeed! In fact, HVO is superior to even conventional diesel in cold weather. The Cold Filter Plugging Point (CFPP) of HVO can be as low as –30°C, which means that your equipment will not freeze during cold January weather.