Biodiesel - The Fuel for the Future

What is Biodiesel?

The diesel engine was invented by Dr. Rudolf Diesel in 1895. He showed his engine at the World Exhibition in Paris in 1900 using peanut oil as fuel. In 1912 Diesel said:

“the use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in the course of time as important as petroleum and the coal tar products of the present time”.

At a time when the Middle Eastern countries are cutting back on oil production, at a time when most developed countries have signed up to the Kyoto Protocol to attempt to reduce global warming, Dr. Diesel’s words are more true now than ever before.

In an attempt to reduce pollution from traffic fumes several “cleaner” fuels have appeared on the market over the last few years – these include:

• Lead free petrol
• Low sulphur diesel
• Liquified petroleum gas (LPG)
• Liquified natural gas (LNG)
• Compressed natural gas (CNG)

All of these fuels are cleaner than the original four-star petrol and high sulphur diesel (DERV) that they replaced but they are ALL fossil fuels. They all come from reserves that were created by geological processes millions of years ago. In other words they are finite and will eventually run out! Furthermore the carbon dioxide released when they are burnt, is released into the atmosphere and adds to global warming.

A promising fuel for the future is hydrogen which when burnt with oxygen produces water vapour. However, for this to be sustainable we must get more energy out of the fuel when we burn it, than is put in to manufacture it!

An alternative, renewable road fuel could be available in Medway today – Biodiesel. Biodiesel is made from vegetable oils by a process called transesterification. Vegetable oil molecules (in both used cooking oils and virgin vegetable oils) are made up of three esters (hydrocarbon chains) attached to a molecule of glycerine. During the transesterification process the glycerine is replaced by alcohol to make biodiesel. The biodiesel process normally uses methanol and sodium hydroxide (caustic soda) as reagents and produces glycerine by-products and soapy water waste.

Advantages of Biodiesel

Biodiesel has many advantages compared to mineral diesel:

• Reduces atmospheric carbon dioxide increase by 100%.
  
• Reduces sulphur dioxide emissions by up to 100%.
  
• Reduces soot by up to 60%.
  
• Reduces carbon monoxide emissions by up to 50%.
  
• Reduces hydrocarbon emissions by up to 50%.
  
• Reduces all polycyclic aromatic hydrocarbon (PAH) emissions by up to 50% and some carcinogenic PAHs by up to 97%.
  
• Reduces nitrous oxides emissions by up to 10%.
  
• Biodiesel is a renewable energy source.
  
• Biodiesel can be mixed in any proportion with ordinary mineral DERV.
  
• Biodiesel is biodegradable and non-toxic.

Additionally the energy balance for biodiesel manufacture is at least 2.5:1. In other words at least 2.5 times more energy is released by burning biodiesel than is required to grow the crops, harvest them and turn them into biodiesel. This additional energy is captured from the sun when the oil seed crops are grown.

Disadvantages of Biodiesel

There are some minor disadvantages of biodiesel:

• Biodiesel delivers approximately 5% less torque, power and fuel efficiency.
  
• If 100% biodiesel is used for over 100,000 miles then rubber fuel system components can deteriorate. (Note – most European diesel engines are manufactured using synthetic rubber parts that do not deteriorate with biodiesel.
  
• Manufacturers fuel-related warranties generally only cover 5% biodiesel mixtures.

The Medway Project

The Waste Forum is currently running a project to establish the first biodiesel manufacturing plant in Medway. The Forum is hoping to find sufficient funding to enable it to construct the plant and have it producing biodiesel in Medway by the end of 2004. If you are interested in quoting the Forum for work related to this project please see the Biodiesel Feasability Brief. If you would like to learn more about the project, where it will be possible to buy biodiesel etc. please email vicechair@medwaywasteforum.org.uk .