Energy generation and use MR. BANKS 7 TH GRADE SCIENCE

Transcription

1 Energy generation and use MR. BANKS 7 TH GRADE SCIENCE

2 Worldwide energy use As the world becomes more populated and technologically advanced, the demand for energy has increased. Before electricity was discovered, worldwide energy use was around 20 x Btu, basically all of which for heating.

3 Worldwide energy use Energy use is divided into three main categories Heating Transportation Electricity

4 Heating The earliest form of energy use. Buildings, vehicles, food, water, industry. Whenever something is heated energy must be used.

5 Transportation Transportation is one of the biggest uses of energy today. Our world works based on the idea that we can easily transport things long distances, including transporting ourselves.

6 Electricity Incredibly useful for doing work. Can be stored for later use. Makes modern life possible. Used in an ever increasing portion of our lives.

7 Renewable vs nonrenewable energy Renewable energy: an energy source that can be replenished within about a century. Never run out or can be regrown Nonrenewable energy: an energy source that can take millions of years to replace, if they can be replaced at all. Can t be replaced in a time frame that matters to humans.

8 Fossil fuels Includes coal, oil, natural gas, and gasoline. Provides 85% of the world s energy. Formed from the remains of prehistoric plants and animals.

9 Getting fossil fuels Coal Must be mined from where it was formed underground. Oil and natural gas Easier to extract than coal, it just has to be pumped to the surface.

10 Advantages of fossil fuels Large amounts of electricity can be generated relatively cheaply. Transporting oil and natural gas is easy. Large amounts of energy are stored in a small amount of fuel.

11 Disadvantages of fossil fuels Produces pollution Carbon dioxide, a greenhouse gas, thought to be the major force behind global warming. Sulfur dioxide, leads to acid rain. Oil spills Coal mining is dangerous, and strip mining destroys the environment.

12 Disadvantages of fossil fuels They are NOT renewable resources. It takes millions of years to form new fossil fuels. Our consumption of fossil fuels has doubled every 20 years since the year 1900.

13 Disadvantages of fossil fuels It is not a question of if we run out of fossil fuels, but when. Most projections leave us with about 100 years of fuel left.

14 Disadvantages of fossil fuels This is particularly bad in terms of oil since we use it to make plastics, wax, grease, asphalt, and many other products.

15 Nuclear power Nuclear power: using nuclear fission from radioactive materials to generate heat and thus electricity. Usually uranium or plutonium, sometimes thorium.

16 Advantages of nuclear power Very cheap to produce power. Very little pollution, very little waste. Lots of energy for very little fuel. Reliable power.

17 Disadvantages of nuclear power Dangerous waste Though not much waste is produced, it is incredibly deadly. Not renewable Once we dig up all the uranium there will never be any more.

18 Disadvantages of nuclear power Meltdown When a nuclear power plant has problems, it can be incredibly damaging to people and the environment. Thankfully this is a rare occurrence and is usually contained.

19 Disadvantages of nuclear power Chernobyl The worst nuclear accident in history. Happened in 1986 in the Ukraine, then controlled by Soviet Russia. Everyone living within 20 miles of the plant were evacuated and most not allowed to return, about 350,000 people total. Parts will be dangerous for more than 10,000 years.

20 Solar power Solar power: Solar Cells, called photovoltaic" or "photoelectric" cells convert light directly into electricity. In the sun, a one meter square can power two 90 watt light bulbs.

21 Solar power Solar furnace, a huge array of mirrors to concentrate the Sun's energy into a small space and produce very high temperatures to generate electricity.

22 Advantages of solar power The fuel, sunlight, is free and renewable! Especially useful for low power objects like small lights and battery chargers. Produces no waste.

23 Disadvantages of solar power Doesn t work at night or when it s cloudy. Need a battery backup or other power sources. Can be unreliable, no power when it s cloudy. Expensive to build solar power stations compared to other power plants.

24 Wind power Wind power: Wind blows and turns the blades of a windmill to generate electricity. Before electricity, wind was used to do work in other ways.

25 Advantages of wind power The fuel, wind, is free and renewable! Produces no waste. The land beneath can still be used for farming. Works at night.

26 Disadvantages of wind power Wind is unpredictable and some days there may be none. Need a battery backup or other power sources. Can kill birds and bats. Kind of noisy, with a constant swooshing sound day and night. Some people don t like the look of them.

27 Hydroelectricity Hydroelectricity: A dam is built to trap water from a river. Water is allowed through tunnels in the dam to generate electricity.

28 Advantages of hydroelectricity The fuel, water, is free and renewable! No waste is produced. More reliable than wind or solar. Power generation can be regulated to meet demand. Can be used to store drinking water.

29 Disadvantages of hydroelectricity Dams are expensive to build. Damming rivers floods large areas upstream. Can effect water quality in an area. Can effect fish migration and reproduction.

30 Biomass Biomass: Plant and animal products and wastes (trash, manure, woodchips, corn, cornstalks) and turn them into fuels like methane and natural gas. These can then be used to generate electricity or heat.

31 Advantages of biomass The fuel is waste, so it makes sense to use it. It is also very cheap because of this. It is renewable, we ll never run out of food waste. Results in less demand on earth s resources.

32 Disadvantages of biomass Collecting enough waste can be difficult. Some wastes aren t available all year. The fuel is burned, so it contributes carbon dioxide Can lead to increased food prices.

33 Geothermal power Geothermal power: Hot rocks underground heat water and produce steam which is used for electricity generation and heating.

34 Advantages of geothermal power The fuel is simply underground water, so it s free and renewable. Once the power plant is built the energy is basically free. No pollution or waste.

35 Disadvantages of geothermal power There are only a few places you can build geothermal power plants. Sometimes geothermal power sites can run out of steam They generally build back up after a few years.

36 Energy use worldwide

37 American energy use

38 American energy use

39 Energy use in Arkansas

40 Energy use in Arkansas

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43 Electricity

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