1. 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.

2. 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.

3. What are biofuels?
• Biofuels are made from natural
products.
• They are renewable fuels and include;
1. Ethanol-based fuels
2. Biogas

4. 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.

5. Advantages of biofuels
 Biofuels are carbon neutral.
 Storage, transport and distribution
costs are low.
 By-products of production can be
burnt in power stations instead of
fossil fuels or used as animal feed

6. 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.

7. 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?