HVO fuel: is fryer fat the miracle fuel we’ve been waiting for?

HVO fuel – much of it from used cooking oil – is being touted as the most viable eco-friendly diesel alternative to date. But is it all it’s cracked up to be? Risa Merl investigates...

In the quest to make yachting more sustainable, the use of alternative fuels has been oft discussed, but making the switch from diesel is far from easy. Many diesel alternatives including biodiesels (known as (Fatty Acid Methyl Ester, or FAME) aren’t ready to be rolled out en masse to superyachts due to safety concerns, storage limitations, bunkering challenges, lack of availability or because their application requires completely overhauling engine room design. 

So, when a renewable, sustainable and biodegradable fuel source known as hydrotreated vegetable oil (HVO) came onto the scene with a promise to cut carbon emissions by up to 90 per cent while also being easy to bunker and use in existing diesel engines, the industry sat up and took notice.

Nordic commercial ships are already using HVO successfully, and on land it’s being rolled out in heavy goods vehicles — the UK’s Royal Mail, as just one example, has announced plans to switch its fleet of postal delivery vehicles to run on HVO fuel. HVO has been making headlines worldwide, but is it really the miracle that some are proselytising?

A greener fuel

What’s under little dispute is that it has become increasingly important to find a greener fuel alternative in yachting. “In order to mitigate the risks associated with climate-related effects, we must support the transition to a carbon-neutral emissions future,” says Ross Wombwell, head of technical services at British Marine, which recently collaborated with the International Council of Marine Industry Associations (ICOMIA) on a report titled Pathways to Propulsion Decarbonisation for the Recreational Marine Industry. The report points out that while recreational boats are a relatively small contributor to greenhouse gas (GHG) emissions, accounting for 0.4 and 0.7 per cent of CO2 emissions emitted by the transport sector in the EU and US, respectively, the marine leisure sector is still investigating options to reduce GHG emissions.

The push to find a cleaner fuel source is also being driven by client requests, from owners and charterers alike. “There is definitely an increased interest in alternative fuels, and the discussion is becoming more frequent with owners, crew and shipyards,” says Ed Beckett, a partner at Burgess and naval architect in the broker’s New Construction team. On the new-build side, HVO is now being negotiated into specifications, and some yachts in the Burgess charter fleet already have experience using HVO. “Discussion on other fuels such as methanol is also increasing, but the implications and challenges of including this in a new yacht are much more significant,” Beckett says.

The 44-metre Sanlorenzo Lammouche, managed for charter by Burgess, has been trialling HVO after taking delivery of 15,000 litres of Cristal Power XTL 100 fuel sold by Fioul 83 last year. Trying out an alternative fuel is just part of Lammouche’s approach to sustainability, along with using eco-friendly toiletries and improving efficiency of the water taps on board. 

Lammouche’s captain, Jean-Maxime Berthet, says responding to the sometimes negative perception of superyachts was also a factor in the decision to try HVO. “The increase of protests in the South of France by activists against yachts was starting to be a concern, and I wanted to have an answer,” Berthet says. While yachts might not be the biggest contributor to GHG, he adds, “a yacht is still a huge energy consumer for only 12 passengers”.

Many HVO fuels, like the kind Lammouche trialled, are derived from used cooking oil (UCO). This is why you might’ve heard that HVO allows yachts to be powered by fryer fat. To turn UCO into HVO, it is synthesised with the addition of hydrogen and the induction of a catalytic reaction. These create a paraffinic diesel fuel with a chemical structure that’s nearly identical to traditional diesel, or “fossil diesel” as it’s known in the biz. HVO is one of the sustainable paraffinic fuels that’s regulated in both Europe and the US by the European EN 15940 and US ASTM D975 fuel standards, respectively.

HVO’s similarity to diesel is why it can be used as a direct replacement in diesel engines, and it can also be mixed with diesel. (Other diesel alternatives, like methanol, require extensive engine room overhauls.) “From an operational standpoint, it’s good to know that HVO can be mixed with fossil fuel in any ratio, so if you’re in an area where you cannot get HVO, you can still bunker diesel,” says Bram Jongepier, senior specialist at Feadship De Voogt Naval Architects.

Switching to HVO is seemingly such an easy win that engine manufacturer MTU has approved it for use in its MTU series 2000 and 4000 engines. “HVO sustainable diesel can be used in any of our engines today,” says Denise Kurtulus, vice president of Global Marine at Rolls-Royce Power Systems. While Kurtulus sees methanol fuel as the long-term goal for cleaner emissions, she deems HVO as a winning stopover in the energy transition to methanol engines. “There is a transition, because we can’t just jump into (using methanol), but one thing we can do now is start to use HVO. The technology is there, and using HVO reduces CO2 emissions by 90 per cent.”

Not all HVO fuels are created equal 

When ICOMIA conducted its study on alternative fuels, it looked at HVO derived from UCO as well as HVO made with alternative feedstocks such as palm oil. “The risks associated with alternative feedstocks include the use of palm oil and the environmental impacts that can arise from land transformation for its cultivation,” Wombwell says.

According to the World Wildlife Fund, palm oil cultivation can lead to wide areas of tropical forests being cleared to make room for it. Not only does palm oil harm the plant and animal species that are displaced, but a common way to clear the forests is to burn them down, which creates carbon dioxide, further contributing to climate change. Adding to palm oil’s ills, it’s linked to soil and water pollution and soil erosion. “A key concern is ensuring that any HVO supply is truly sustainable and ethical – for example, avoiding deforestation or conversion of much needed agricultural land,” says Beckett.

Whether you get UCO or a palm oil derivative depends wholly on the source. The European Commission plans to phase out palm oil used in transport fuel by 2030. However, until then, palm oil might still pop up in HVO. It’s been reported that an HVO fuel used in transport in Sweden, for example, was found to be nearly 50 per cent palm oil. “You’ll find a mix internationally depending on location and supplier,” says Wombwell, noting that Crown Oil, which supplies marine HVO in the UK, doesn’t support the sale of palm oil and only supplies International Sustainability Carbon Certification (ISCC) verified waste-derived HVO.

“HVO is becoming more available as we speak and more production facilities are coming online every year, however, it’s very important to ensure the fuel carries the correct ISCC certification,” says Jongepier. “In order to have a low [environmental] impact, HVO should be produced from waste flows — used cooking oils or animal waste fats — and not from palm oil or other feedstocks. Due diligence from the operator is required.”

Shipyards and alternative fuels

Feadship started considering certified alternative fuels back in 2009 on its futuristic concept Aeon. At the time, the Dutch builder looked at BTL (biomass-to-liquid) made from algae, but production has yet to ramp up to make BTL a viable solution. Then they tested the chemically similar GTL (gas-to-liquid) on the 46-metre Feadship Kiss, launched in 2015. “However, since GTL is still fossil based, we had to wait for a bio-based EN 15940 fuel, which turned out to be HVO,” says Jongepier. “After we got the go-ahead from our engine suppliers in 2018/2019, we’ve been informing owners, captains, management companies, etc. of this possibility. We intend to use HVO as factory fill for every new Feadship from now on and keep informing the existing fleet of the option.”

Some yachts in the Feadship fleet have already switched over to HVO, and the 84-metre Feadship Obsidian, launched in 2023, was the first new build to use HVO. “Because Obsidian’s owner has had a strong drive to reduce impact from the beginning, he embraced the introduction of HVO on his yacht,” says Jongepier.

Azimut-Benetti is also making a commitment to HVO. At the last Cannes Yachting Festival, the Italian builder presented the results of a certified independent scientific panel, including input from Professor Massimo Santarelli of the Politecnico di Torino’s Energy Department, Eni Sustainable Mobility, Lloyd’s Register and Superyacht Eco Association, a non-profit organisation created by the Yacht Club de Monaco and Credit Suisse.

Azimut-Benetti has signed an agreement with Enilive (Eni Sustainable Mobility) for the supply and use of HVOlution, an HVO biofuel produced from 100 per cent renewable raw materials. “This is a very important step forward in the industry’s decarbonisation process as it is the first agreement in this sector,” says Alessandro Rossi, Azimut-Benetti Group’s chief technical officer. HVOlution is produced in Enilive’s Venice and Gela biorefineries from waste raw materials and vegetable residues, or from oils generated from crops that do not compete with the food chain.

The new Azimut Magellano 60 has cruised the Mediterranean powered by HVO. “The tests recorded a reduction in well-to-wake CO2 emissions of more than 80 per cent compared to a yacht of comparable size powered by fossil fuel,” says Rossi. And Azimut-Benetti has begun using HVOlution biofuel during sea trials, technical tests and transfers of prototypes and newly produced boats.

The pros and cons

Once an owner decides they want to go with HVO, approval is needed by the yacht’s classification society, engine and generator manufacturers and the yacht’s insurer. While the process is now getting easier as more engine manufacturers have approved the use of HVO, because Lammouche was an early adopter, they went through a challenging six-month approbation process that included discussions with the engine and generator manufacturers, class approval, as well as agreement from the owning and management companies. “At first, Caterpillar and John Deere were confused by HVO, which was still pretty new to them, and thought we were going to use FAME, a first-generation biodiesel, which is unstable and requires a precise blend,” says Captain Berthet.

What’s especially appealing about HVO is that it can drop in to existing diesel engines, enabling yachts to start using it fairly quickly after gaining approval. Using HVO only requires minor modifications to the engine room, says Jongepier, such as adding a secondary calibration for the tank sensors in the engine’s Monitoring Control System, due to HVO’s slightly lower density as compared to fossil diesel, and having a calibrated ring for the fuel separator on board. Captain Berthet notes that the fuel purifier might also require different plates, and ideally there should be a dedicated day tank for storing HVO. There are also questions over the fuel gauge accuracy when using HVO.

A boon to HVO is that it doesn’t degrade a yacht’s performance. “During trials we tested Obsidian on HVO as well as fossil diesel to check for any relevant differences,” says Jongepier. “There were none mechanically, and only about three per cent higher fuel consumption in volume [for HVO].”

After a season of testing it out, Berthet says the pros of HVO are numerous, including that it’s approved by most engine manufacturers, has a 10-year shelf life and requires no heating or recirculation during storage. It’s also made a notable difference in the charter experience on board Lammouche. “As it’s smokeless and odourless, there’s an immediate improvement in guest comfort because we don’t have any fumes or soot coming through our exhaust,” he says. “Clients can now swim without inhaling gasoline, and they don’t feel shame by polluting the earth while they are having fun.”

If this sounds almost too good to be true, that’s because in some ways it is. In the case of HVO’s eco-friendly claims, while CO2 is massively reduced and particulate matter is also cut down by up to 85 per cent, the stats don’t bode quite as well for nitrogen oxides, with NOx emissions only reduced by up to 27 per cent. According to the United Nations Environment Programme, NOx is 300 times more potent at warming the atmosphere than CO2, so the relative lack of reduction of NOx is no small thing.

Perhaps the most pressing downsides concern HVO’s availability and cost. As of now, HVO is more expensive than diesel. “However, the difference is what you compare it with,” says Jongepier. “Compared with the cheap tax-free Gibraltar fuel, it might be three times as expensive, but some yachts are running on more expensive fuel anyway. When Savannah bunkered with HVO last September, it meant a price increase of only 10 per cent. At the same time, more demand and more production of HVO should lead to lower prices.” Tax measures will influence pricing as well — for instance, in the Netherlands pure HVO is only five to 10 per cent more expensive than diesel.

When it came to the cost being passed down to charter clients, Captain Berthet said the premium was fairly reasonable, with only a 1.8 per cent increase in the APA for a week of charter, which equates to about €800 (£685) more per week. Not a bad price to pay so your family doesn’t breathe in fumes while you play in the water.

How easy is it to source HVO?

“Availability remains limited, however, we are starting to see this improve,” says Beckett. “There is a little bit of a chicken-and-egg scenario in play at the moment with sufficient demand being needed to develop the shoreside infrastructure and the shoreside infrastructure being needed to develop the demand.” The investment in the infrastructure to make the fuel widely available is substantial, and confidence from the fuel suppliers over long-term demand of HVO is likely a key factor in their decision-making process.

It’s hard to say how long it will take for HVO to reach critical mass and become widely available and less costly — Azimut-Benetti predicts HVO production will grow by 2030. A big factor will be the yachting industry having a unified message and supporting HVO as the fuel of choice. An important step is having major shipyards, like Feadship and Azimut-Benetti, already throwing their weight behind HVO and committing to use it. Azimut-Benetti is also working on future projects to develop a distribution network, which will involve offering owners the possibility of refuelling with HVO through a distribution hub.

Government buy-in will help as well, as Wombwell notes, “HVO could be an important part of our pathway to a carbon neutral future, however, there needs to be greater support from the government to enable its quicker uptake as it is a technology-ready drop-in solution for many exiting vessels. We should not put off being better in the short term whilst we wait for the perfect solution to be invented.”

There is wide agreement that HVO is the best option on the journey to cleaner fuel, especially in terms of reducing emissions in the existing fleet of yachts. “The availability of a drop-in solution is very important,” says Jongepier. “Depending on engine type, most of these yachts could switch over to HVO, which would result in a big reduction of the yachting fleet’s impact on global warming. And since there is probably nothing more unnecessary than a yacht, it is most necessary to operate it with the smallest footprint possible.”