What is Biodiesel?

Biodiesel is a generic term used for bio-based fuels with properties similar to diesel. The term is often used to describe FAME but is not exclusive to describing fuels containing FAME. 

Biodiesel (FAME) is derived from renewable sources, such as plant oils, animal fats, recycled cooking oil and waste biomass, and when burned in an internal combustion engine, it releases carbon dioxide and water vapour. Biodiesel, as a pure fuel (B100) rather than a blend, can be a net zero-emission fuel if carbon released during combustion is offset by the carbon absorbed during the growth of the resources used in the production. Feedstocks must be sustainably sourced for biodiesel to be a sustainable fuel option.

Adoption of biodiesel is currently limited by sustainable resource and fuel availability globally

Biodiesel challenge

Biodiesel is considered a "drop in" fuel because existing technology (infrastructure and engines) for diesel can be used, however the impacts of varying fuel properties from different feedstock types are uncertain.

Biodiesel challenge

Exploring the advantages of biodiesel as a marine fuel

  1. Low risk of environmental contamination: in the event of a spill, biodiesel poses a lower risk of environmental contamination than other fuels as it is biodegradable.
  2. Compatibility: Biodiesel is considered a “drop in” fuel, functionally equivalent to petroleum, as it requires little or no modification to existing diesel technology.
  3. Safe operation: Safety is not considered a new challenge for the industry, as existing safety mitigations for diesel are well established and can be applied to biodiesel.

Risks and disadvantages

  1. Feedstock sustainability challenges: large-scale production of (1st and 2nd generation) biodiesel may require significant amounts of land and water resources, creating sustainability implications.
  2. Feedstock demand: there is competing demand for feedstock from other sectors, and conflict over the best use of feedstock e.g., food (1st generation biodiesel).
  3. Uncertainties: Its lower energy value, sensitivity to oxidation stability and affinity to microbial activity and material compatibility need to be understood and addressed when stored and in use on board ship. 

Differences between biodiesel fuels

Different generations of biofuels have been defined, with increasing potential for generating high quantities of sustainable feedstock.

  1. 1st generation biodiesel is produced from edible vegetable oils, animal fats or oils and fats that are primarily used for food
  2. 2nd generation biodiesel is produced from lignocellulosic biomass and other waste streams such as agricultural residues and used cooking oils
  3. 3rd generation biodiesels are produced from non-food feedstocks and are characterised by high yield and rapid growth rates. Feedstocks include micro- and macro-algae.

FAME feedstock may be any generation of feedstock.