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Turning coffee grounds into Biofuel

The UK drinks over 95 million cups of coffee a day, producing vast amounts of spent coffee grounds. Most end up in landfill, where they release methane.

But these waste grounds contain valuable oils that can be converted into biofuel, offering a practical way to reduce waste and cut reliance on fossil fuels.

Why coffee waste is suitable for biofuel production

Spent coffee grounds are rich in oils, typically making up 10 to 20% of their composition, which makes them an effective raw material for biofuel. These oils can be extracted and converted into biodiesel using standard processes.

Coffee waste is also widely available and consistently produced in large volumes, particularly across the food and beverage sector. This makes it a reliable feedstock compared to some other biofuel sources.

As a waste product, it does not compete with food crops or require additional land use, making it a practical option for reducing both waste and reliance on fossil fuels.

How do you turn spent coffee grounds into biofuel?

Turning spent coffee grounds into biofuel involves extracting oils from the waste and converting them into biodiesel using a process called transesterification. This separates and refines the oil into a fuel that can be used in transport.

Once processed, the biodiesel can be blended with conventional fuels and used in existing engines. For example, blends like B20 are already being used to power vehicles, including London’s double-decker buses.

How the process works:

Spent coffee grounds are collected through restaurant waste collection and office waste collection services
The grounds are dried to remove excess moisture
Oils are extracted from the coffee waste
The oil undergoes transesterification to convert it into biodiesel
The final fuel is blended with diesel or petrol for use in vehicles

This provides a practical way to turn everyday waste into a usable fuel.

Coffee ground recycling and waste management

Most spent coffee grounds are disposed of alongside food waste, typically through existing commercial food waste collection services. Without separation, this material is usually sent for anaerobic digestion or composting, rather than being recovered for higher value uses like biofuel.

To produce biofuel, coffee grounds need to be collected separately or segregated at source so they can be processed for oil extraction. This is usually done through dedicated collections or as part of a structured food waste stream where separation is in place.

In the UK, dedicated coffee waste collection services are only available in the biggest cities. For example, First Mile’s collection service in London.

While biofuel is one of the most valuable uses, spent coffee grounds are also used in other ways when properly recovered:

Anaerobic digestion to produce biogas and electricity
Composting and soil improvement in agriculture and landscaping
Use as a fertiliser due to their nutrient content
Manufacturing applications, including biomaterials and textiles
Odour control and filtration in commercial settings

What are the advantages and disadvantages of using coffee waste as a biofuel?

Below, we look at the key advantages and disadvantages of using spent coffee grounds as a biofuel, including the environmental benefits, practical limitations, and how it compares to other fuel sources.

Advantages

Reducing carbon emissions by removing coffee ground waste from general business waste disposal.
Reduction in the use of crop-derived biofuels like palm, sugarcane and corn oil, which have a questionable environmental reputation.
High-quality oil may be used to power vehicles.
Requires less filtering than other oils like spent cooking oil.
There is a renewable source of coffee waste, which is unlikely to stop.
Reducing the required volumes of commercial waste collections and their associated business waste collection costs.

Disadvantages

Spent Coffee Ground oils cannot be used as biofuels alone as infrastructure is often designed for diesel and petrol.
Relies on coffee consumption. If this stops for any reason, the entire industry will collapse.
Re-processing the spent coffee grounds removes their potential as plant nutrients, disrupting the carbon cycle.
Even if renewable, burning spent coffee biofuel still emits greenhouse gasses.

Is using coffee grounds as a biofuel classed as green energy?

Green energy refers to the generation of energy from sources that are renewable in a human timescale, and spent coffee grounds certainly fall within this range. Given current consumption rates, coffee grounds are an extremely resilient source of green energy.

A study by the University of Loughborough (using spent coffee from their cafe) suggests that the spent coffee generated annually in the UK has the potential to replace 4.4% of the coal used for electricity generation in the country.

Using coffee grounds as a biofuel – FAQs

Our business waste experts answer commonly asked questions regarding using coffee to produce biofuel.

Are coffee grounds classed as a biofuel?

Coffee ground waste is unusable as a biofuel in its spent state and needs further processing to extract its liquid oils (remember, biofuels must be a liquid or gas!)

The coffee ground can also be upcycled into useful materials like bioplastics, and the remaining fibres can be used to create coffee logs, which may be categorised as a source of biomass energy.

Realistically, how sustainable is it to use coffee waste as a way to power vehicles?

This is not a question of whether it’s possible but how much the re-using process can scale.

As mentioned earlier, the fleet of double-decker London buses has already been powered by a B20 biofuel since 2017. 20% of this biofuel comes from Spent Coffee Ground oils.

Can I heat my business using spent coffee grounds?

You can certainly use coffee logs made of spent coffee grounds to heat your business if you have a kiln or wood/coal burner.

However, the reality is that most buildings in the UK use gas heating systems, and infrastructure is difficult to replace from one day to another.

We understand that with the current business gas prices everyone is looking to save on heating costs, especially as winter is coming.

What are the challenges with turning coffee grounds into biofuel?

The main challenges are collecting and separating coffee waste at scale, the cost of processing and refining the oils, and the need to blend the final fuel with diesel due to existing engine and infrastructure limitations. It also relies on consistent coffee consumption and still produces emissions when used.