Biofuels
- Our increasing population also needs more energy for industry, transport and other uses. However, most people agree we need to reduce our use of fossil fuels. Replacements for them are biofuels.
- Biofuels are fuels that are made from biomass (plants, animals or their waste products).
Biogas
- Microorganisms decompose waster material or plants to produce biogas.
- Biogas is usually about 70% methane and 30% carbon dioxide.
- It can be burned to power a turbine to generate electricity, or to heat water and produce steam to heat a central heating system.
- It can be used as a fuel for cars and buses.
Biodiesel
- This can be used in vehicles and is very similar to normal diesel. The vehicle doesn’t need to be altered much for it to run on biodiesel.
- Biodiesel is made from vegetable oils, animal fats or waste cooking oil.
Ethanol
- Ethanol can be burnt as fuel. It’s a cleaner fuel than petrol or diesel, producing fewer pollutants.
- Ethanol is produced by using yeast to ferment glucose. Materials like sugar cane, corn and barley can be used as a source of glucose in ethanol production.
- Cars can be adapted to run on a mixture of ethanol and petrol which know as ‘gasohol’.
Advantages and Disadvantages
- Biofuels are sustainable as the plants can be grown quickly. This makes them a renewable energy source, unlike fossil fuels such as coal and crude oil which will run out.
- Burning biofuels is carbon neutral, whereas burning fossil fuels produces a lot of carbon dioxide. It is carbon neutral as the plants grown take in carbon dioxide, but the carbon dioxide is put back into the atmosphere when the fuel is burnt.
- Biofuels are fairly clean and produce less particulates (can cause lung disease) than fossil fuels.
- Burning biofuels doesn’t produce a significant amount of sulphur dioxide, which can cause acid rain, but a lot if produced from power stations burning fossil fuels.
- However, growing the crops for biofuels uses up a lot of land which could be used for growing crops for food.
- Vehicles and power stations need to be adapted to run on biofuels which costs time and money.