A question from a customer I thought I would change into a post for the blog.
“Morning Adam, We have a fleet of ##### trains and are looking to switch to a biofuel, particularly HVO. We have had issues with FAME in the past. Is it the same stuff. Can they be switched in and out?”
Hence you can see a rail customer wanted some support and comparisons and I found writing the answer I could make a blog post out of this. So please read on.
Biofuels have gained significant attention in recent years as the world seeks to reduce its carbon footprint and move towards more sustainable sources of energy. Among the various biofuels available, Hydrotreated Vegetable Oil (HVO) has emerged as a noteworthy option due to its distinct properties, such as its chemical similarity to fossil diesel, drop-in compatibility, superior stability and stricter lab testing alarm limits, making it suitable for a wide range of applications. But how does HVO stack up against other biofuels like biodiesel, ethanol, and biogas? Let’s explore the unique characteristics of HVO and how it compares to other biofuel types.
What is HVO?
HVO, or Hydrotreated Vegetable Oil, is a type of renewable diesel made through hydrotreating plant or animal fats. Hydrotreating is advantageous compared to transesterification as it results in a fuel that is more stable, has a higher cetane number, and is free of oxygen, making it closer in properties to conventional diesel. Unlike traditional biodiesel (FAME), which uses a process called transesterification, HVO undergoes hydrotreatment, meaning hydrogen is used to remove oxygen from the raw materials. The result is a fuel that closely resembles fossil diesel and can be used in most existing diesel engines without modifications. Its chemical similarity to regular diesel makes it suitable for applications in heavy transport and industries that need consistent, reliable fuel performance. This process ensures that the final product has a high cetane number, better combustion characteristics, and minimal impurities.
HVO vs. Biodiesel
One of the most common biofuels compared to HVO is biodiesel. Both are derived from renewable sources like plant oils or animal fats, but they differ significantly in their production process, properties, and applications. Biodiesel, produced through transesterification, results in a fatty acid methyl ester (FAME). This process involves reacting the raw oils with methanol in the presence of a catalyst, resulting in a product that contains oxygen within its molecular structure (esters). This oxygen content is beneficial for combustion but also makes biodiesel more prone to oxidation and degradation over time.
HVO, on the other hand, has several advantages in terms of quality and performance, such as improved stability, longer shelf life, and better cold-weather performance. Moreover, HVO’s cold-weather performance is generally better than biodiesel, making it a preferred choice in colder climates where biodiesel’s tendency to gel can be problematic.
However, biodiesel also has its own merits, particularly in terms of production simplicity and the widespread availability of feedstocks. The choice between HVO and biodiesel often depends on specific use cases, regulatory support, and cost considerations.
HVO vs. Ethanol
Ethanol is another popular biofuel, particularly in the automotive sector with 10% of UK petrol using Ethanol as of writing as opposed to 7% of uk diesel using FAME. Produced from fermentation of sugars, ethanol is commonly blended with petrol to reduce emissions and dependence on fossil fuels. Ethanol production involves fermenting sugars from sources like corn, sugarcane, or cellulosic biomass into alcohol, which is then distilled and dehydrated to create a usable fuel. While ethanol has potential in reducing greenhouse gas emissions, it is not as versatile as HVO, but if you have a spark engine it’s the likely go to liquid fuel in the renewables category.
Ethanol is primarily suited for spark-ignition engines due to its high octane rating, which improves combustion efficiency, meaning it finds its home in petrol-powered vehicles. HVO, conversely, can directly replace fossil diesel and be used in any diesel engine without adjustments. This makes HVO more flexible, especially for sectors like transport and construction, which predominantly rely on diesel engines.
Additionally, HVO has a higher energy density compared to ethanol, meaning vehicles using HVO can travel further per litre. This is something you will be familiar with between petrol and diesel too. However, ethanol plays an important role in the transition towards sustainable energy, particularly in regions where petrol-powered vehicles dominate.
HVO vs. Biogas
Biogas, which is primarily methane, is produced from the anaerobic digestion of organic matter like food waste or manure. This process involves the breakdown of organic materials by bacteria in the absence of oxygen, resulting in a mixture of methane and carbon dioxide. Biogas is another renewable energy source with a lot of potential, especially in the context of circular economy solutions where waste products are converted into fuel. Biogas is usually compressed and used for power generation or as a substitute for natural gas.
When compared to HVO, biogas is less energy-dense and requires dedicated infrastructure, such as modified engines or gas networks, but is a good fuel for quite large stationary engines. While biogas has advantages in reducing waste and promoting a closed-loop system, it lacks the convenience of HVO’s drop-in replacement capabilities. It equally requires very regular monitoring by oil analysis, often weakly as the Hydrogen sulphide produces sulphuric acid in the engine from the biogas contaminants from sulphurous biological feedstock.
That said, biogas is well-suited for local applications where waste-to-energy systems are established, whereas HVO is ideal for sectors seeking an easy switch from traditional diesel to a renewable alternative. Many farms run their entire electricity off biogas systems and indeed in energy production biogas is likely to be a key energy source in the years to come.
Environmental Impact
When discussing biofuels, it’s important to consider the environmental impact of each option. All biofuels, including HVO, biodiesel, ethanol, and biogas, offer significant reductions in carbon emissions when compared to fossil fuels. However, there are nuances to each fuel’s environmental performance.
Both HVO and biodiesel can be made from waste oils, such as used cooking oil and industrial waste fats, animal fats, or sustainably sourced vegetable oils, which reduces competition with food crops and contributes to the circular economy. By using waste oils, HVO production helps repurpose materials that would otherwise be discarded, reducing waste and promoting resource efficiency. This approach not only minimises the environmental impact of waste disposal but also provides an additional revenue stream for industries that generate waste oils.
All biofuels can raise concerns over food-versus-fuel debates, depending on the feedstock used. Biogas, on the other hand with its waste-to-energy model, is highly effective in reducing emissions from organic waste and providing renewable energy and is less likely to be a land usage issue as the waste is using the area anyway.
Performance and Practicality
One of the key advantages of HVO is its practicality as a ‘drop-in’ fuel. Users do not need to make modifications to their engines, and logistics companies can use existing infrastructure without needing special tanks or pumps. Its quality consistency also makes it preferable for businesses that can’t afford interruptions or fluctuations in fuel quality. Biodiesel, while also renewable, typically needs blending eg usually 7 to 10% in europe and has higher maintenance concerns, such as issues with engine deposits.
Ethanol, meanwhile, requires blending limits (usually E10 in the UK) to be compatible with existing vehicles, and biogas demands dedicated infrastructure. HVO’s ability to deliver near-identical performance to diesel without these obstacles provides an easy-to-implement solution for businesses and fleets, as it requires fewer infrastructure changes and reduced maintenance compared to other biofuels, making it a practical choice for those looking to lower their carbon footprint without disrupting operations. However, each fuel has its specific advantages that suit different contexts and needs.
The disadvantage of HVO
I have spoken of many of the advantages of HVO but it does as already mentioned have the food vs fuel issue where you have to choose how to use the land. Equally its scalability compared to FAME is much less and this tends to drive its price up in the market place as one of the more expensive fuels.
The 2030 Target and Biofuel Role
As countries such as the UK set ambitious targets for reducing carbon emissions by 2030, the pressure is mounting to adopt cleaner energy solutions. However, there are growing concerns that battery capacity and electrical infrastructure might not be sufficient to support the complete electrification of transport by this deadline. Electric vehicles (EVs) are facing challenges related to battery material shortages, high costs, and the need for significant upgrades to power grids. From my own experience owning a mild hybrid, I faced a 12-month lead time to receive the vehicle, and even simple repairs can take a couple of months with some manufacturers. These delays illustrate that relying solely on EVs may not be practical, and biofuels could provide a more immediate and viable solution as part of the energy mix.
In this context, biofuels like HVO, biodiesel, ethanol, and biogas should be considered as part of the energy mix. They offer a viable, immediate solution that can leverage existing infrastructure while helping bridge the gap until electric technology becomes more feasible for widespread adoption. Biofuels can ensure that millions of diesel and petrol engines already in use continue to operate with reduced emissions, making them an essential component of the transition strategy towards a more sustainable future.
The Importance of Testing and Engine Oil Impact
While the use of biofuels like HVO, biodiesel, ethanol, and biogas can significantly reduce emissions, it’s crucial to understand their impact on engine performance and maintenance. Different biofuels can affect engine oil differently, influencing factors such as oxidation stability, deposit formation, and overall oil life. These factors are critical to engine performance because they determine how well the engine can maintain efficiency, prevent wear, and avoid costly maintenance issues. For instance, biodiesel has a higher tendency to oxidize, which can lead to the formation of engine deposits and affect oil quality. Similarly, ethanol and biogas may introduce different byproducts that could alter engine oil properties.
HVO, with its stable chemical structure, generally has less impact on engine oil compared to biodiesel. However, all biofuels, including HVO, can have varying effects depending on the engine type, operating conditions, and blend ratios. Therefore, regular testing of both the fuel and engine oil is essential to ensure optimal engine health and performance. Laboratory analysis can help identify potential issues early, such as increased wear metals, viscosity changes, or contamination, which are critical for maintaining the reliability and longevity of engines running on biofuels.
Equally, with HVO the cleanliness requirements are at least twice as strict as fossil fuel diesel so maintaining system cleanliness becomes even more important.
Conclusion: A full look at Biofuels
Each biofuel has its own merits, and the choice largely depends on the specific requirements of the application, as well as regional regulations and infrastructure. HVO stands out due to its flexibility, performance, and environmental benefits, particularly as a drop-in replacement for diesel. However, biodiesel, ethanol, and biogas each serve specific niches and contribute to reducing our reliance on fossil fuels in their own ways.
Biodiesel may be preferred for its simplicity in production and cost-effectiveness, ethanol for its role in petrol engines, and biogas for its waste-to-energy efficiency. HVO offers an optimal balance of practicality and performance, especially for applications requiring minimal disruption in transitioning from fossil fuels.
Ultimately, the path to a greener future will likely involve a mix of these biofuels, each playing a role in reducing emissions and transitioning towards a more sustainable energy landscape. Technological advancements will also play a crucial role in improving the adoption rates and efficiency of these biofuels, making them even more viable solutions in the future. Regular testing of both fuel and engine oil will be essential to ensure that engines continue to perform efficiently and reliably, regardless of the biofuel used. Laboratory analysis of fuel quality is just as critical as testing engine oil, as it helps identify any contaminants or inconsistencies that could impact engine performance, reduce efficiency, or cause long-term damage. Ensuring both the fuel and oil are in optimal condition will support better performance, reduced maintenance costs, and longer engine life.
If you would like to learn more about testing your machinery fluids and would like advice on how to improve your green credentials of your machinery then get in touch.