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6 Biofuels p.274.

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Presentation on theme: "6 Biofuels p.274."— Presentation transcript:

1 6 Biofuels p.274

2 Objectives Students should learn:
that biofuels can be made from natural products by anaerobic fermentation that there are advantages and disadvantages in using ethanol-based biofuels.

3 Outcomes Most students should be able to:
describe how yeast can produce ethanol for fuel describe the advantages and disadvantages of using ethanol-based fuels describe how second-generation biofuels are being developed. Some students should also be able to: interpret economic and environmental data relating to the production of fuels by fermentation and their uses.

4 Specification Biofuels can be made from natural products by anaerobic fermentation. Deforestation has occurred so that: ■ crops can be grown from which biofuels, based on ethanol, can be produced

5

6 Biology B3 4.6 Biofuels Answers to in-text questions a They are fast-growing and contain a lot of sugar that can be fermented. b There is no overall increase in the levels of carbon dioxide in the air as a result of the industry in question. Summary answers 1 2 a i 725 million gallons. ii 730 million gallons. iii 4850 million gallons. b Use of ethanol as a fuel grew steadily through the 1980s and 1990s but has increased dramatically in the first 7 years of the 21st century. Any other points giving suggested reasons can be credited.

7 Compulsory slides you must complete and use;

8 biofuels can be made from natural products by anaerobic fermentation
How Is it increasing? Give a word equation for fermentation in microbes Say what gasohol is Could use

9 advantages and disadvantages in using ethanol-based biofuels.

10 ‘fun’ activity Show these 2 movies
texaco gasohol movie top gear biodiesel

11 Slides you may wish to use;

12 Boardworks GCSE Separate Sciences 2009 Other Uses for Micro-organisms
What are biofuels? Biofuels are fuels made using living organisms or the waste that they produce. These include: Biogas – produced from the breakdown of organic material. Ethanol – produced by the fermentation of sugar from plant material. Unlike fossil fuels, biofuels provide a renewable source of energy. Biofuels are also thought to have less of an impact on the environment than fossil fuels.

13 What is ethanol-based fuel?
Boardworks GCSE Separate Sciences 2009 Other Uses for Micro-organisms What is ethanol-based fuel? Ethanol produced by the anaerobic fermentation of glucose by yeast is used to make fuels such as gasohol. It is successfully used as a fuel for cars in Brazil and the USA. Brazil produces ethanol from sugar cane, whereas the USA uses maize. Photo credit: © Shutterstock 2009, Joao Virissimo Teacher notes Biofuel production is increasing - between 2000 and 2005 ethanol production doubled. The British Government's Renewable Transport Fuel Obligation currently requires 2.5% of fuels sold at the pump to be biofuels. This will increase to 5% by 2010, while the EU has a target of 5.75% of all transport fuels to be from biological sources, also by 2010. Gasohol normally contains 10% ethanol and 90% petrol. This allows gasohol to be used in unmodified petrol engines.

14 How is ethanol produced?
Boardworks GCSE Separate Sciences 2009 Other Uses for Micro-organisms How is ethanol produced? Ethanol is produced by carrying out the following steps. 1. Glucose is obtained from either: maize starch broken down into glucose by the action of carbohydrase enzymes sugar cane juices. 2. Yeast are added to the glucose, they respire anaerobically, producing ethanol and carbon dioxide. Photo credit: © Shutterstock 2009, Jim Parkin Ethanol production plant utilizing corn as a feed stock located in the middle of farm land in the Dakotas. 3. Once fermentation is complete pure ethanol is obtained by distilling the mixture.

15 What are the advantage of biofuels?
Boardworks GCSE Separate Sciences 2009 Other Uses for Micro-organisms What are the advantage of biofuels? Biofuels are thought to produce lower greenhouse gas emissions and particulates than conventional transport fuels. Biomass is a renewable source of energy, therefore biofuels are a more sustainable form of energy as it will not run out. Using biofuels instead of fossil fuels can also help to conserve the world’s non-renewable fuel resources. Photo credit: © Shutterstock 2009, Tony Mathews Biofuels can also be cheaper to use for drivers, as governments often introduce schemes to encourage people to reduce their emissions.

16 Boardworks GCSE Separate Sciences 2009 Other Uses for Micro-organisms
Carbon neutral? Teacher notes This voting activity enables the individual opinions of the class to be represented graphically. It could be used as a precursor to a debate on the use of biofuels. The class could vote again after the debate to see if their opinions have changed. This may be a good opportunity to discuss what is meant by the term carbon neutral.

17 What are the disadvantages of biofuels?
Boardworks GCSE Separate Sciences 2009 Other Uses for Micro-organisms What are the disadvantages of biofuels? Biofuels are not completely carbon neutral because energy is used in the production and transportation of the biofuel. This energy is often provided by fossil fuels. There are also concerns that the production of biofuels could affect food production. As biofuel production increases, more land is being used for growing crops for fuels such as gasohol. This could mean that less land is being used for food production, causing a shortage of food. Land previously unused is being harnessed for biofuel crops, this could contribute to a loss in biodiversity. Teacher notes The term carbon neutral is used to mean an substance or an act that absorbs the same amount of carbon dioxide as it produces. Some biofuels themselves are said to be carbon neutral, however more carbon may be released during the manufacturing and transport process. Gasohol includes petrol, using this fuel therefore involves burning petrol – a fossil fuel. Currently there are 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, therefore it needs to be transported causing more fuel to be used.

18 Boardworks GCSE Separate Sciences 2009 Other Uses for Micro-organisms
Which biofuel?

19 Using ethanol as biofuel for cars
Advantages Co2 neutral Little pollution Efficient Can mix with petrol so current cars can be converted to it Disadvantages Expensive to produce/right conditions needed Use lots of land/need large amount of plant material Still pollution if mixed with petrol Lots of cellulose waste – can we develop this in future?

20 Which biofuel would you use to:
Generate electricity? Heat your home? Which biofuel would you use to: Cook your food? Power a vehicle?

21 Yak faeces Energy output: 2 Poor Ease of use: 3
OK, need to dry out before use Ease of production: 4 Simple - if you keep yaks! Uses: 1 Mainly for cooking in special stoves FACT FILE Equipment needed: 3 Modified stoves Fumes produced: 1 Very smoky!

22 Willow Energy output: 3 Ease of use: 3 Ease of production: 3 Uses: 2
Good Ease of use: 3 Good Ease of production: 3 Two years to produce crop Uses: 2 Mainly in modified power stations FACT FILE Equipment needed: 3 Modified burners Smoke can be produced if burning is not controlled carefully Fumes produced: 3

23 Gasohol Energy output: 4 Excellent Same as ordinary petrol
Ease of use: 4 Requires a fermentation plant to produce the alcohol which is then added to petrol. Ease of production: 2 Uses: 2 Mixed with petrol in standard cars FACT FILE Some cars need to be modified (particularly if alcohol:petrol mix uses more than 10% alcohol) Equipment needed: 4 Fumes produced: 4 Cleaner than petrol alone

24 Biodiesel Energy output: 4 Excellent Ease of use: 4
Same as standard diesel Ease of production: 2 Requires a chemical plant to extract the oil from crops and then modify it to make diesel. Uses: 2 In diesel-engined road vehicles FACT FILE Equipment needed: 5 Standard diesel engine Fumes produced: 4 Cleaner than standard diesel

25 Biogas Energy output: 4 Excellent Ease of use: 4 Same as standard gas
Ease of production: 2 Requires a digester which can convert old organic wastes to methane Uses: 4 Heating, cooking and power stations FACT FILE Equipment needed: 5 Standard gas appliance Fumes produced: 4 Very clean


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