Biofuels are produced using chemical reactions and heat to break down feedstock such as starches, sugars, and other molecules. The term biofuels includes first and second generation biodiesel which are distinguished by production process and the type of required feedstock. First generation biodiesel is produced through a process called esterification using edible crops such as rapeseed, palm and other vegetable oil.
Second generation biodiesel also known as Hydrotreated Vegetable Oil (HVO) is produced through a process of hydrogenation, i.e. treatment with hydrogen. HVO is much more flexible when it comes feedstock as it can be produced from low quality waste like animal fats and cooking oil or from non-edible sources like algae, straw and even mushrooms.
As a fuel, biodiesel has a number of advantages. The raw material is cheap, the production process of converting feedstock to energy is relatively easy and biodiesel emits significantly less CO2 when combusted. And it can be using with existing infrastructure and engine technology with minimum modifications and even blended with diesel.
Yet the likelihood of biodiesel becoming a major alternative fuel for trucks seems increasingly unlikely for a number of reasons. First is efficiency; biodiesel has lower energy output (about 10% less than conventional diesel) which means higher quantities of fuel is needed. Then there is the fact that biodiesel might not be suitable for winter conditions since the temperature at which the fuel solidifies is much higher than diesel. The usage of biodiesel could also cause operational issues like clogging and injector chocking.
Beyond efficiency and technology though, the wide-scale adoption of biodiesel presents bigger questions around sustainability. Critics of first generation biofuels argue that the production of feedstock leads to deforestation.
Then there is also the potential conflict first generation biodiesel has with food production and the impact this could have on food prices as increasing amounts of agricultural land gets designated for fuel feedstock production. Concerns like this have had a major impact on biodiesel’s green credentials prompting the European Commission to conclude that crop-based biofuels would not be eligible to count towards EU renewable transport targets for national governments.
Given these challenges, proponents of biodiesel have shifted their focus to less water and land intensive alternatives like HVO manufactured from organic waste products. The high quality of HVO as a fuel and the potential many oil producers, particularly those in Europe, see in using it to address overcapacity and profitability issues in refineries, has increased investment in this area. At least three new European HVO investments have been announced recently which will help the market grow nearly 88.5% within the next 3 years. There is also growing interest from Asia and the Middle East.
So might HVO be the answer biodiesel’s demise? Well, yes and no. HVO does have a lot of advantages but it’s still a fuel that is expensive to produce in most parts of the world and suffers from a lack of sufficient feedstock. Despite growing investments, mass production of HVO is a challenge which means that it is unlikely to dominate the alternative fuel market any time soon though it certainly can change the way the biodiesel sector looks today. Taken as a whole, it is perhaps best to conclude that the most viable use of first and second generation biodiesel will be as a blend in today’s fossil fuels.
While biodiesel might not be the immediate answer to a carbon-free future, it can certainly be a complement to other alternative fuels such as LNG and electromobility. I have prepared a guide that outlines the pros and cons of some of today’s most widely discussed alternatives to diesel.
Environment and Innovation Director at Volvo Trucks.