Unusual sources of biofuels

Poo-powered cars? Algae electricity? Public transport running on kitchen-oil and congealed fat? These are only some of the biofuel alternatives currently being developed!

24 May 2019

Photobioreactor in lab algae fuel biofuel industry Algae fuel or algal biofuel is an alternative to fossil fuel that uses algae as its source of natural deposits

By Mariusz Bogacki, Researcher and Science Communicator, Edinburgh

Poo-powered cars? Algae electricity? Public transport running on kitchen-oil and congealed fat? These are only some of the biofuel alternatives currently being developed!

We all know that fossil fuels – widely used today as a source of energy – are non-renewable resources and carry many threats, mainly related to pollution and degradation of our natural environment. What many of us aren’t aware of however, is the energy production potential of biofuels – fuels produced through contemporary biological process.

Up until recently, biofuel was most commonly only thought of as a type of renewable energy source deriving from plants. However, as the field of biotechnology becomes more and more advanced, researchers are now exploring more unusual, untapped energy production territories.

Below are just three of some of the most promising – and unusual – alternatives for biofuel production currently being tested.

Fat what?

Defined as a very large mass of solid waste in a sewerage system (largely made of congealed fat, oils and sanitary items), fatbergs have been a concern for cities such as Birmingham and London for some time now. Thankfully, one of the major large-scale biofuel production companies in the UK came up with a solution to turn this dirty problem into clean biofuel. The answer lies in the process of converting fat oil and grease (FOGs) – collected from sewer systems and stored at waste treatment facilities – by removing contamination and converting it into a clean oil suitable for the production of biodiesel.

Magic algae…

Algae are very small aquatic organisms that convert sunlight into energy. Some of the algae store energy in the form of natural oils, which then can be converted into biofuels. Proponents of this solution argue that algae crops could be 10 or even 100 times more productive than traditional bioenergy crops (e.g. land based plants). The incredible efficiency of these organisms is not the only reason for their growing fan base – just like plants, algae need carbon dioxide to grow. In order words, algae collects the CO2 out of the atmosphere, therefore making it a nearly carbon neutral fuel source.


Today’s waste-to-fuel solutions are no longer merely limited to inorganic recycling. Human waste has recently joined the team of biofuel sources. One of the most promising methods is the hydrothermal liquefaction (HTL). It is a process during which a considerable amount of heat and pressure is applied to wastewater, breaking down its chemical components into biocrude product that can be refined into a biofuel. Roughly 60% of the waste material is converted into biocrude and researchers estimate that a single person could generate over 10 litres of biocrude oil a year – turning humans into the ultimate organic biofuel factories!

Sources of biofuel are all around us and the technology to produce it is advancing every day. Admittedly obstacles to its full implementation at an industrial scale are often down to lobbying and legislation, while others, to the industry itself. However – where there’s a will there’s a way, and the next alternative technological breakthrough awaits courageous (and unconventional!) scientists and researchers.