# IB Physics – Global environmental physics Where does our electricity come from? Castle Peak, West Kowloon; China Light and Power Lamma Island, outlying.

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IB Physics – Global environmental physics Where does our electricity come from? Castle Peak, West Kowloon; China Light and Power Lamma Island, outlying islands; Hong Kong Electric What fuel is used to generate electricity in each of these power stations?

IB Physics – Global environmental physics Thermal power generation The Coal-fired power station in Gelsenkirchen, Germany which claims to be the cleanest in Europe.

IB Physics – Global environmental physics Pollution? Smoke stack from US power station in Pittsburgh in 1975 - The company installed wet scrubbers to minimize emissions in a \$42 million environmental improvement project 1.Write down the equation for the combustion of fossil fuels 2.List any pollutants formed and explain where they come from. 3.Describe what effects may these have on (i) our health and (ii) the environment? 4.Suggest what can be done to reduce the amount of pollutants produced in fossil fuel combustion 1.Write down the equation for the combustion of fossil fuels 2.List any pollutants formed and explain where they come from. 3.Describe what effects may these have on (i) our health and (ii) the environment? 4.Suggest what can be done to reduce the amount of pollutants produced in fossil fuel combustion

IB Physics – Global environmental physics Why does this happen? 1.What impression are these videos trying to give? 2.Is this fair? 1.What impression are these videos trying to give? 2.Is this fair?

IB Physics – Global environmental physics World Energy demand By the end of this lesson you should be able to; 1.Outline the principal mechanisms involved in the production of electrical power. 2.Define the energy density of a fuel. 3.Discuss how choice of fuel is influenced by its energy density. 4.Outline the historical and geographical reasons for the widespread use of fossil fuels. 5.Discuss the energy density of fossil fuels with respect to the demands of power stations. 6.Discuss the relative advantages and disadvantages associated with the transportation and storage of fossil fuels. 7.Describe the environmental problems associated with the recovery of fossil fuels and their use in power stations. By the end of this lesson you should be able to; 1.Outline the principal mechanisms involved in the production of electrical power. 2.Define the energy density of a fuel. 3.Discuss how choice of fuel is influenced by its energy density. 4.Outline the historical and geographical reasons for the widespread use of fossil fuels. 5.Discuss the energy density of fossil fuels with respect to the demands of power stations. 6.Discuss the relative advantages and disadvantages associated with the transportation and storage of fossil fuels. 7.Describe the environmental problems associated with the recovery of fossil fuels and their use in power stations.

IB Physics – Global environmental physics The proportions of different energy sources used to generate electrical energy in 2006 Other 0.8% Combustible renewables and waste 1.0% Other 18.0% Hydro 16.2% Oil 6.7% Gas 19.7% Coal 40.1% Nuclear 15.1% Non renewable Waste 0.3%

IB Physics – Global environmental physics Thermal power energy transformations Chemical energy in fuel Thermal energy in steam Kinetic energy in turbine Electrical energy from generator Efficiency = Useful energy out x 100 % Total energy in 100 MJ 32 MJ Efficiency = 32 MJ x 100 % = 32 % 100 MJ

IB Physics – Global environmental physics How it works Electromagnetic induction java applet

IB Physics – Global environmental physics Block diagram of thermal power generation Generator Electricity to grid Water Boiler High pressure steam Fuel Air Turbine Condenser Low pressure steam Cooling water in Cooling water out 1.Explain why we are currently very dependent on fossil fuels for our energy security? 2.Outline how geographical features effect the location of a thermal power plant? 3.Outline some of the transport and storage issues for fossil fuels? 1.Explain why we are currently very dependent on fossil fuels for our energy security? 2.Outline how geographical features effect the location of a thermal power plant? 3.Outline some of the transport and storage issues for fossil fuels?

IB Physics – Global environmental physics Energy density of selected fuels Food Energy density / MJkg-1 Fossil FuelsEnergy density / MJkg-1 carbohydrates17.2Gas (methane)55.5 fats38.9coal, anthracite31.4 proteins17.2coal, bituminous> 23.9 Bio mass fuels Energy density / MJkg-1 coal, sub- bituminous 17.4 - 23.8 charcoal29.0coal, lignite< 17.43 dung, air dry12.0diesel45.3 rice husks15.5 gasoline, automotive 45.8 wood, green10.9kerosene46.3 Explain why energy density is important for power generation companies

IB Physics – Global environmental physics Estimating the energy density Procedure 1.Design a method to carry out your experiment to compare the energy density of a solid fuel, liquid fuel and a gaseous fuel. 2.List the independent, dependent and control variables 3.Record your raw data in a table, including uncertainties. 4.Process any data as required to calculate the energy density of each fuel and present your results appropriately. 5.Write a conclusion on your findings. Procedure 1.Design a method to carry out your experiment to compare the energy density of a solid fuel, liquid fuel and a gaseous fuel. 2.List the independent, dependent and control variables 3.Record your raw data in a table, including uncertainties. 4.Process any data as required to calculate the energy density of each fuel and present your results appropriately. 5.Write a conclusion on your findings. If time is limited, just carry out the experiment for one fuel and share results with the rest of the class

IB Physics – Global environmental physics Conclusions 1.Which fuel has the highest energy density? 2.What causes the largest uncertainties in your data? 3.How can you reduce these uncertainties? 4.What recommendations can you make to power generation companies? 1.Which fuel has the highest energy density? 2.What causes the largest uncertainties in your data? 3.How can you reduce these uncertainties? 4.What recommendations can you make to power generation companies? Complete all the questions on GEP 4 and mark with the solutions sheet

IB Physics – Global environmental physics Design – Fuels heating water (GEP6) A fuel is used to heat some water. Design an experiment to investigate one variable which affects the final temperature of the water. A fuel is used to heat some water. Design an experiment to investigate one variable which affects the final temperature of the water.

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