It’s a green world Energy flow Part 2

How do we use biomass? Starter Biomass supplies us with more than just food. How can biomass be used by humans?

Energy flow Learning objectives Success criteria Student will learn about: Biomass Biofuels How biogas is formed Students can: Recall examples of fuels Describe the different methods of transferring energy from biomass Explain the reasons for developing biofuels

What is biomass energy? Biomass energy is one of the oldest forms of energy. The biomass stored in wood can be burned for heating and cooking. Photo credits: © 2007 Jupiterimages Corporation Animal dung can also be burned for energy.

Biofuels Biofuels release smaller amounts of carbon dioxide than conventional fuels when burnt. e.g. Drax power station CO2 output reduced 5% when Elephant grass is burnt instead of coal In Lille, France the buses run on biogas. In Britain 2% of fuel sold is biogas.

Advantages of biofuels Renewable. Cause less pollution. Help towards a countries energy self reliance.

Task - Biofuels Answer questions 9 – 16 on page 74 – 75 of the textbook 9. From the sun 10. To make food so that it can grow 11. Biomass 12. Energy is released (and pollutants) 13. Because fossil fuels produce a lot of carbon dioxide, which is linked to global warming 14. Methane and some carbon dioxide 15. Biogas produces less harmful waste gases than petrol 16. So they can be replaced quickly

More than our fair share? Biofuels have many advantages but using land to grow fuel reduces the area available for food crops. Humans take the biggest slice of the Earth’s resources, using about 40% of the biomass produced on land. How would growing biofuels affect this? Should humans leave more biomass for other organisms?

Task Answer questions 17 – 18 on p75 of textbook 17. Fossil fuels have a lot of energy but produce a lot of harmful waste, they are also not being replaced; Biogas is cleaner and is easily replaced but does not produce as much energy. 18. In a drought, the farmer may have to use his crops to feed his family; he will have no seeds to sell or plant the following year.

Plenary One answer to the diminishing fuel resources may be to reduce the amount of energy we use. List ways you could reduce energy use at school and home.

Energy flow Learning objectives Success criteria Student will learn about: Biomass Biofuels How biogas is formed Students can: Recall examples of fuels Describe the different methods of transferring energy from biomass Explain the reasons for developing biofuels