2. Fuels for Different Uses Used for 5 main purposes: Cooking Transportation Manufacturing Heating & cooling buildings Generating electricity to run machines & appliances Suitability of a fuel for each application depends on the fuel’s energy content, cost, availability & safety, and the byproducts of the fuel’s use

3. Electricity – Power on Demand Energy in fuels is often converted into electrical energy in order to power machines because electricity is more convenient to use Can be transported quickly across long or short distances Disadvantages of electricity: Difficult to store Other energy sources have to be used to generate it

4. How is Electricity Generated? Electric generator: converts mechanical energy (motion) into electrical energy convert the movement of a turbine into electrical energy Uses a turbine (wheel that changes the force of a moving gas or liquid into energy that can do work) water is heated by burning a fuel (coal, gas) or by fission of uranium (in nuclear plants) to produce steam to that turns the turbine The turbine spins a generator to produce electricity

5. How a Coal-Fired Power Plant Works Fossil fuels are burned to release heat. Heat boils water to produce steam. Steam turns the blades of a turbine. The turbine sets the generator in motion. Electricity is generated.

7. Energy Use in the U.S. People in developed societies use much more energy than people in developing countries do The U.S. uses more energy per person than any other country in the world except Canada & the United Arab Emirates Uses more than 25% of its energy resources to transport goods & people (trucks & personal vehicles) Residents of U.S. & Canada have some of the lowest gasoline taxes

8. Energy Use in the U.S.

9. How Electricity is Generated in the U.S. Coal: 50% Nuclear:20% Natural Gas:18% Hydroelectricity7% Oil:3%

11. Fossil Fuels The remains of ancient organisms that changed into coal, oil, or natural gas Provide most of the energy used today 2 main problems Supply is limited Obtaining and using them causes environmental problems

12. World Energy Use

13. How Fossil-Fuel Deposits Form Coal Forms from the remains of plants that lived in swamps hundreds of millions of years ago Much of the coal in the eastern U.S. formed about 320 million to 300 million years ago Formation of coal: As ocean levels rose & fell, swamps were covered with sediment Layers of sediment compressed the plant remains Heat & pressure within the Earth’s crust caused coal to form Oil & Natural Gas Result from the decay of tiny marine organisms that accumulated on the bottom of the ocean millions of years ago

14. Coal Two major advantages of coal Relatively inexpensive Needs little refining after it has been mined

15. Coal Mining & the Environment Surface mining has a bigger effect on the environment Toxic chemicals can leach into nearby streams A lot of research focuses on 2 things: Developing better methods of locating Developing less damaging methods

16. Air Pollution Higher-grade coals produce more heat and less pollution than lower- grade coal Sulfur is a major source of pollution when coal is burned Clean-burning coal technology has dramatically reduced air pollution in the U.S.

17. Petroleum Oil that is pumped from the ground (also called crude oil) Petroleum product: anything that is made from crude oil Accounts for 45% of the world’s commercial energy use Most of the world’s oil reserves are in the Middle East

18. Steps in the Oil-Drilling Process Exploration wells are drilled If oil can be extracted at a profitable rate, wells are drilled Oil is transported to a refinery to be converted into fuels & other petroleum products

19. Environmental Effects of Using Oil When petroleum fuels are burned, they release pollutants Contribute to the formation of smog and cause health problems Sulfur: a pollutant that contributes to acid rain The carbon dioxide released may contribute to global warming 2 things that have reduced air pollution from cars in many areas: Emission regulations Technology (catalytic converters)

20. Natural Gas Provides 20% of the world’s nonrenewable energy Methane (CH4) Has become more common to use because it produces fewer pollutants than burning other fossil fuels

21. Fossil Fuels & the Future Supply about 90% of the energy used in developed countries Cost will likely increase as the demand for energy resources increases Oil reserves: oil deposits that can be extracted profitably at current prices using current technology The relative cost of obtaining fossil fuels influences the amount of fossil fuels that we extract from the Earth