BIOFUELSWith over 7 billion people on earth the demand for fuel is higher than ever. It is important that the demand is met with an equal supply but at the moment we rely on limited quantities of fossil fuels for our energy.

What are biofuels and why are they being developed?

• Biomass is a renewable source of energy, therefore biofuel is a more sustainable form of energy as it will not run out

• Biofuels are thought to produce lower greenhouse gas emissions and particulates than conventional transport fuels

• Using biofuels instead of fossil fuels can also help to conserve the world’s non-renewable fuel resources

• Biofuels can also be cheaper to use for drivers, as governments often introduce schemes to encourage people to reduce their emissions

The graph represents usage of gasohol in the US and it shows that development of renewable sources of fuel are on the rise.

Progress with biofuel so far

Through collaboration between numerous universities, farmers and the U.S. Department of Agriculture, biofuel production is on the rise.

Renewable energy consumption is shown in the light green segment of this pie chart and it shows there is still a lot of progress to be made with usage of biofuels.

Gasoholhttp://www.youtube.com/watch?v=TYHoeIvb8I4 At the moment, Gasohol seems to be the most achievable alternative fuel source.Gasohol contains a mixture of petrol and alcohol and it releases the same amount of energy as regular petrol.The mixture burns more cleanly than petrol, however some cars will need to be modified if they are to use Gasohol.

Production of Biofuels

The alcohol in Gasohol is produced by using bacteria, enzymes and steam or chemical treatments to break down the cellulose in plant biomass.The end products of the break down are sugars which can be anaerobically fermented by yeast to produce ethanol.Unfortunately the production of the alcohol requires vast quantities of biomass and this has encouraged deforestation to make space for the crops.

Fermentation in Microbes – The Chemistry behind it

Sugar Ethanol + Carbon Dioxide

Different Types of BiofuelsThe term “biofuel” describes a huge variety of renewable fuel sources:• Biogas• Ethanol• Gasohol• Biodiesel• Dried animal faeces (in poor countries)• Willow wood• Biogas

Ethanol-Based Fuels

Advantages

• Renewable• Can be used in cars as

fuel• Ethanol can be mixed

with Petrol to make Gasohol which can be used in most cars with no problems

• Does not produce toxic gases in combustion so less polluting

• Carbon neutral

Disadvantages• Expensive to produce• Still pollution if mixed with

petrol• Deforestation needed to make

more useable land• Car engines need special

modifications to be able to use pure ethanol as fuel

• A lot of plant material is needed to produce the ethanol, leaving lots of cellulose waste

• Ethical issue of using plants to produce fuel instead of feeding the hungry

How is ethanol produced?Ethanol is produced by carrying out the following steps.

3. Once fermentation is complete pure ethanol is obtained by distilling the mixture.

1. Glucose is obtained from either:

2. Yeast are added to the glucose, they respire anaerobically, producing ethanol and carbon dioxide.

maize starch broken down into glucose by the action of carbohydrase enzymes

sugar cane juices.

Biofuels: Carbon Neutral?Biofuels are not completely carbon neutral because energy is used in the production and transportation of the biofuelThis energy is often provided by fossil fuelsThere are also concerns that the production of biofuels could affect food production.As biofuel production increases, more land is being used for growing crops for fuels such as gasohol.This could mean that less land is being used for food production, causing a shortage of food.

Land previously unused is being harnessed for biofuel crops, this could contribute to a loss in biodiversity.

BiogasBiogas is created when organic material is anaerobically digested by anaerobes. During production, there is a solid byproduct called digestate.This can be used as a biofuel or fertilizer. Biogas consists of methane. Landfill gas is created in landfills due to natural anaerobic digestion and is a less clean form of biogas. Dried manure, charcoal and wood are examples of solid biofuels.

Biofuel Videohttp://www.youtube.com/watch?v=GOFbsaNeZps Top Gear: Biodiesel

(in case I’m desperate and have ran out of things to say)