Biofuel

To be a bio-fuel a material has to be "bio" (derived from a recently living plant or animal source) and "fuel" (capable of being combusted in a manner that gives heat).
This leaves a wide range of potential candidates:

• any plant or animal oil or fat new or used (e.g. old chip fryer oil)
• any unused parts of plants (husks, bark, leaves)
• methane derived from anaerobic digestion of waste including sewage
• waste paper and wood
• animal bodies and waste
  
• crematory off-gases
• fermentable sugars and cellulose can become alcohol
  
• cow and other ruminant dung
• specifically grown trees chipped and pelletized
• general garbage and trash

edit; My 2¢.

Pros. Been around for a number of years. No computer controls. Parts are easy to find. Parts are usually cheap compaired to other diesels. Will basically "bolt in" when swapping out a Chevrolet V8 gas engine. Gets pretty decent mileage. Can be run on other fuels besides diesel fuel such as biodiesel, waste vegetable oil, used motor oil and transmission fluid. A fair amount of info can be found on the internet about different repairs or preventive measures.

Cons. Not exactly a powerhouse. Has about the pulling power of a 305 gas V8. Problems on some older engines of the same family were cracked engine blocks, broken crankshafts, cracked heads, to name a few.

Cost:

• Once the technology is widely available, biofuels can be significantly less expensive than gasoline and other fossil fuels, particularly as worldwide demand for oil increases, therefore increasing oil and gasoline prices to unheard of levels.

Source Material:

• Whereas oil is a limited resource that comes from specific materials, biofuels can be manufactured from a wide range of materials including crop waste, manure, and other byproducts, making it a efficient step in recycling.

Renewability:

• It takes thousands of years for fossil fuels to be produced, but biofuels are much more easily renewable as new crops are grown and waste material is collected.

Security:

• By reducing dependence on foreign fuel sources, countries can protect the integrity of their energy resources and make them safe from outside influences.

Economic Stimulation:

• Because biofuels are produced locally, biofuel manufacturing plants can employ hundreds or thousands of workers, creating new jobs in rural areas. Biofuel production will also increase the demand for suitable biofuel crops, providing economic stimulation to the agriculture industry.

Biodegradability:

• Biofuels are easily biodegradable and far safer to handle than traditional fuels, making spills less hazardous and much easier and less expensive to clean up.

Neutral Carbon Emissions:

• When biofuels are burned, they only release carbon that was recently acquired, that is, part of the natural carbon cycle. This is an important difference to the carbon released by fossil fuels, which has been sequestered under the ground for millions of years. CO2 from fossil fuels is responsible for the runaway greenhouse effect that is causing global warming.

• The disadvantage of biofuels is that despite being a renewable source of energy the levels of power/energy it produces are not high enough (compared to fossil fuels) to be used commerically i.e. for industry, power stations etc.
• Despite the many positive characteristics of biofuels, there are also many disadvantages to these energy sources. The main issue is producing biofuels in a sustainable way. This means an emphasis on agricultural practices that do not use rainforests / other endangered habitats or food crop producing land or extensive irrigation or fertilization. Some Biofuels are more harmful than others.

Rainforest and natural habitat destruction:

• Palm oil can be especially damaging but is cheaper than other alternatives. Most palm oil is produced on destroyed rainforest habitat.) Unilever is the world's biggest purchaser of palm oil. The Center for Orangutan Protection concluded orangutans there could be extinct in Borneo by 2011.

Greenhouse gas reduction:

• Rapeseed may produce more CO2 than fossil fuels - (link below).
• Shell is working to develop the fuel ethanol from wheat straw to reduce waste and emissions - (link below).
• It takes 840 years for a palm oil plantation to soak up the carbon emitted when rainforest is burnt to plant the crop.
• Modern agriculture uses a lot of farm machinery and a lot of petroleum-based fuel to run that machinery, so that the fuel invested to create biofuel can offset any possible savings from using biofuel as a substitute for petroleum-based fuels.
• Several studies have been conducted to analyze the carbon footprint of biofuels, and while they may be cleaner to burn, there are strong indications that the process to produce the fuel - including the machinery necessary to cultivate the crops and the plants to produce the fuel - has hefty carbon emissions.
• Biofuels have a lower energy output than traditional fuels and therefore require greater quantities to be consumed in order to produce the same energy level.

Affect on existing agriculture and water supplies:

• Biofuel production can adversely affect food and water supplies to poorer communities and income from agriculture for those communities. It can contribute to deforestation and soil erosion.
• Also, because land ownership is so important to survival, human rights are often very sensitive to any change in land use.
• As demand for food crops such as corn grows it could also raise prices for necessary staple food crops. Malaysia & Indonesia currently meet about 87% of global palm oil demand. China is currently the world's largest importer of palm oil, accounting for one third of all global trade. Biofuel is made from things such as corn, which may be more needed in the form of food than they are as fuel.

Advantages

1. Biofuels are any solid, liquid or gas that has been derived from biomass. It can be produced from any carbon source that is easily replenished such as plants. This means it is very eco-friendly as the fuel is a renewable resource.

2. The waste products can be recycled as they are natural resources. The waste product will also be bio-degradable.

3. Biofuels are carbon neutral meaning they will not give off greenhouse gases such as carbon dioxide.

4. Biofuels can be created anywhere in the world.

5. Once the technology is widely available, it will be much cheaper than fossil fuels as it is made from renewable resources.

Disadvantages

1. At the moment the energy created from biofuels is not sufficient enough for industrial facilities and factories.

2. To create more land to create crops for biofuels it could affect habitats of wild plants and animals as we would still need land to grow crops for food.

3. At the moment biofuels are not sustainable without affecting food prices and production.

4. Farmers would make more money growing biofuel crops therefore they may stop growing food crops and this would lead to a rise in food prices and put people at the risk of starvation.