The first long-haul flight powered by biofuels took off on 18th May 2021. An Air France-KLM flight from Paris to Montreal used a mix of conventional jet fuel and a sustainable aviation fuel (SAF) made from used cooking oils. Also, the UK Government has recently announced that it will mandate the introduction of E10 fuel (petrol containing up to 10% of sustainable bioethanol) from September this year.
Although this is positive news, there is more that can be done. According to the International Energy Agency (IEA), transport biofuel production expanded 6% year-on-year in 2019, and 3% annual production growth is expected up to 2024. However, this falls short of the sustained 10% output growth per year needed until 2030 to align with the IEA’s Sustainable Development Scenario (SDS). The SDS outlines a major transformation of the global energy system, showing how the world can change course to achieve universal access to energy, reduce the severe health impacts of air pollution and to tackle climate change.
In addition to policy support, the IEA highlights the need for innovation to reduce costs in order to to scale up both advanced biofuel consumption and the adoption of biofuels.
Second generation biofuels
A focus of innovation is the transition from first generation biofuels to second generation biofuels. First generation biofuels are derived from food crops. Sugar or starch derived from feedstock such as corn, sugar cane and soybeans can be converted to bioethanol using yeast fermentation. Oils, such as virgin vegetable oils, can undergo transesterification to produce biodiesel. First generation biofuels are certainly useful, and represent the majority of biofuels available today, but their use can threaten food supplies and biodiversity.
Second generation biofuels, on the other hand, utilise feedstocks that are generally not food crops or are not suitable for human consumption. This can include straw, bagasse, perennial grasses and waste vegetable oil. Common second generation feedstocks may produce more biomass per unit area, because the entire crop is available as feedstock for conversion to fuel, and may be able to grow on land that is not suitable for food crops.
Use of second generation feedstocks to produce ethanol involves two steps: the cellulose and hemicellulose components of the biomass are ﬁrst broken down into sugars; and the sugars are then fermented to obtain ethanol. The ﬁrst step is technically challenging, with research focussing on developing efﬁcient and cost-effective ways of carrying out the process. Up to now, the lack of commercial viability has limited the uptake of cellulose-based second-generation biofuels.
In the context of biofuels for transportation, current research is also focussing on ‘drop-in’ biofuels. In contrast to bioethanol and biodiesel, drop in biofuels are fuels that are functionally equivalent to petroleum fuels that have the potential to replace fossil petrol to reduce high amounts of greenhouse gas emissions from conventional petrol cars, without investing into new vehicles or modifying the old ones.
In May 2021, Neste reported that they are in the final phase of testing a drop-in biofuel that they hope will be suitable for commercial use in existing petrol and hybrid cars.
Drop-in fuels can be produced from oleochemical feedstocks such as vegetable oils and used cooking oils. They can also utilise thermochemical technologies such as gasification, pyrolysis or hydrothermal liquefaction based on lignocellulosic feedstocks.
Third generation biofuels
Third generation biofuels refers to those derived from algae. Microalgal biomass is versatile and can be used to produce bioethanol, by fermentation and biodiesel by transesterification. Algal fuels have very high yields and can be grown almost anywhere temperatures are warm enough. This means that no farm land need be threatened by algae. Algae can even be grown in waste water, so they can provide additional advantages by helping to waste while avoiding taking up any additional land. Algae could also potentially utilise waste carbon dioxide in their cultivation.
Although algae can be grown in open water, in order to optimise yield and control, research into third generation biofuels has at least partly focussed on closed systems such as photobioreactors. However, photobioreactors remain an active area of research in order to make them more cost-effective and scalable.
The future for biofuels in transport
In 2020, the UK government announced the end of the sale of new petrol and diesel cars in the UK by 2030. So do biofuels have a part to play in future transport? It would appear so.
Biofuels may be particularly suited to sectors such as long distance trucking, shipping and aviation where electrification is not a suitable option. Also, one cannot ignore the role that biofuels can play in the production of electricity (“bioelectricity”). So, biofuels can supplement electric transport by reducing upstream emissions in electricity production.
Bioenergy for electricity and heat
According to the IEA, bioenergy accounts for about 10% of world total primary energy supply today. Its contribution to final energy demand across all sectors is five times higher than wind and solar combined. In 2019, bioenergy electricity generation increased by over 5%, but the heating sector remains the largest source.
Unlike biofuels for transport, biofuels for electricity and heat production are not limited to liquids. The Drax Power Station in North Yorkshire (UK) has been converting its coal-fired boilers to use biomass. The station uses a range of biomass feedstocks including wood pellets, sunflower pellets, olive, peanut shell husk and rape meal. The station also uses BECCS technology (“Bioenergy with carbon capture and storage”) to make sure that no carbon is released into the atmosphere from its biomass boilers.
It is apparent that biofuels are an essential component of our future energy supply and in the reduction of greenhouse gas emissions. More innovation is key to unlocking the true potential of biofuels, particularly for transport, to scale-up and improve cost-effectiveness.
Biofuels are promising in many ways, not least because they rely on biomass resources that are more evenly distributed around the world, and because there is the potential to use waste products as raw materials.
Reddie and Grose is excited to be assisting innovative companies in the biofuels sector.
This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.