2013/14 in order to assess the progress of the UK RTFO in complying with the wider EU initiative to reduce carbon emissions, the Renewable Energy Directive. This directive was recently reviewed and agreed in December 2008, and mandates that by 2020, 10 per cent of all automotive fuel consumption by energy content should be sourced from renewable energy sources.
Amid all the uncertainty, it appears likely that the worldwide push for increasing biofuel use as a means of reducing overall carbon dioxide emissions will continue, and one can reasonably expect the biofuels market to continue to grow. Much of the biofuel is shipped internationally by sea. For example, first half figures for the 2008/2009 period indicate that 670 million litres of biofuels were supplied to the UK transport market. Only 8% of the biofuel supplied was produced from within the UK, such that 92% (approximately 616 million litres) of biofuel was imported. A recent report by Pike Research estimated that the global biodiesel and ethanol markets are likely to reach US$ 247 billion in sales by 2020, up from US$ 76 billion in sales predicted for 2010.
In order to meet the necessary targets, the quantity of biofuels shipped both into the UK and worldwide is likely to increase, and it is therefore important for those involved in the carriage of biofuels to understand the issues that need to be considered if these products are to be carried safely, without risking damage to either the ship or the cargo.
Current biofuels
There are presently two main classes of biofuels in widespread use; biodiesel (or more correctly, FAME) and bioethanol. The two are very different in their properties and therefore have different issues to consider if they are to be safely shipped, handled, stored and used. Each will be considered in turn.
FAME/Biodiesel
Biodiesel is a fuel derived from vegetable oils or animal fats, although the term ‘biodiesel’ is too vague a description and we therefore use the more correct terminology, Fatty Acid Methyl Esters (FAME), when discussing these fuels. FAME is the product of reacting a vegetable oil or animal fat with an alcohol (methanol, a petrochemical which is generally derived from natural gas or coal) in a process known as transesterification. When compared to conventional diesel derived from crude oil, vegetable oils and animal fats generally have higher viscosities (which means they are more difficult to pump and store without heating) and are more
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unstable (which means they are more likely to degrade during storage, handling and end-use). The transesterification process brings the properties of the raw materials closer to those of a conventional diesel, making the product more suitable for use as a road transport fuel. However, whilst the FAME produced can be used neat as a fuel, it is more commonly blended with conventional petroleum diesel for use in diesel engines.
The ASTM has described a system of nomenclature for naming FAME/diesel blends (see ASTM D6751). Pure FAME is denoted B100, standing for 100% ‘biodiesel’. Other common blends include B5 (5% ‘biodiesel’ and 95% conventional diesel), B7 (the EN590 European diesel standard allows up to 7% by volume FAME in diesel) and B20 (20% ‘biodiesel’ and 80% conventional diesel). In the UK, a major supermarket chain has introduced B30 (30% ‘biodiesel’ and 70% conventional diesel) pumps onto a number of their forecourts (Motor Consult Update November 2008). However, this fuel is not currently governed by any standards and is not approved for use by many of the major automobile manufacturers.
Raw materials for FAME production
A wide number of raw materials can be used for the production of FAME, including palm oil, coconut oil, rapeseed oil, soybean oil, tallow and used cooking oils. A general FAME cargo might be the product of processing any one of these raw materials, or may indeed be a mixture of FAMEs produced from different raw materials. Each raw material would give FAME of a different chemical composition, with correspondingly different characteristics. For example, if we compare a FAME derived from palm oil (PME) with a FAME derived from rapeseed oil (RME), it is possible to notice an immediate visible difference between the two – namely that at normal UK winter temperatures the PME is likely to be solidified whereas the RME will be a liquid. It is the chemical composition of the raw materials and the FAMEs produced from them that explains many of the different characteristics displayed.
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