Biofuels

• All – know the different types of biofuels.

• Most – will be able to use information to develop a flow diagram to show how bioethanol is made.

• Some – will be able evaluate the disadvantages of bioethanol.

The need for alternative fuels• Most vehicles in the world use petrol or diesel as a fuel.

• Fossil fuels are convenient sources of energy, they are very polluting, and will one day run out.

• Some people have already begun using alternative fuels.

What are biofuels?• Biofuels are made from natural

products.

• They are renewable fuels and include; 1. Ethanol-based fuels2. Biogas

1. Ethanol-based fuels

1. What is the initial starting product used to produce bioethanol?

2. How is glucose produced from maize starch?

3. How is ethanol extracted from the final source?

4. Produce a flow diagram of events for the production of ethanol from maize starch?

5. Ethanol is described as carbon neutral. What does this mean.

Biofuels are carbon neutral.

Storage, transport and distribution costs are low.

Advantages of biofuels

By-products of production can be burnt in power stations instead of fossil fuels or used as animal feed

Disadvantages of biofuels Production needs energy from fossil fuels.

Few UK producers of biofuels, and only small quantities of fuel are made. Biofuels therefore need to be imported, mainly from Brazil and South-East Asia.

High demand for land to plant biofuel crops can lead to deforestation and habitat loss.

2. Biogas

1. What is the main biogas that is produced?

2. What is the starting product used to produce biogas?

3. How do microorganisms break down this product to release the biogas?

4. The reactions that take place are exothermic but biogas production is often limited to hot countries. Why?

5. The generators provide ideal conditions for the fermentation of the carbohydrate. How?