Chapter 13 Achieving Energy Sustainability

1. Chapter 13 Achieving Energy Sustainability

2. Chapter 13Achieving Energy Sustainability • This section will take you through the main types of renewable energy resources: • Biomass • Hydroelectric • Solar • Wind • Geothermal • Hydrogen Fuel Cells

3. How much are we using renewables today? U.S. GLOBAL Energy Use in the United States. Only 7 percent of the energy used in the United States comes from renewable energy resources.

4. Biomass is energy from the Sun Energy from the Sun. The Sun is the ultimate source of almost all types of energy.

5. Biomass • Wood, Charcoal and Manure- burned to heat homes throughout the world. • Ethanol and Biodiesel (biofuels)- used as substitutes for gasoline and diesel fuel. Cause Effect

6. Modern Carbon vs. Fossil Carbon • Is burning biomass (such as wood) is better than burning coal? • Generally, yes: The carbon found in biomass was recently in the atmosphere as carbon dioxide, taken in by the tree. By burning it we put carbon back into the atmosphere - continuing the cycle. Coal is carbon that has been buried for millions of years and was out of circulation until we began to use it. This results in a rapid increase in the concentration of carbon dioxide in the atmosphere. Fossil carbon Carbon in fossil fuels. Modern carbon Carbon in biomass that was recently in the atmosphere. Carbon neutral An activity that does not change atmospheric CO2 concentrations.

7. Biofuels: Ethanol and Biodiesel Liquid biofuels can be used as a substitute for gasoline and diesel. • Biodiesel - A diesel (not gasoline) substitute produced by extracting and chemically altering oil from plants. • Flex-fuel vehicle - A vehicle that runs on either gasoline or a gasoline/ethanol mixture. • Ethanol - alcohol (added to gasoline) made by converting starches and sugars from plant material into alcohol and CO2.

8. The kinetic energy of water can generate electricity Hydroelectricity-electricity generated by the kinetic energy of moving water. The pressurized water behind a dam spins a turbine, generating electricity. This is the second most common form of renewable energy in the world.

9. Types of hydroelectric power systems • Run-of-the-river systems: water is held behind a dam and runs through a channel before returning to the river. • Water impoundment: water is stored behind a dam and the gates of the dam are opened and closed controlling the flow of water. • Tidal systems: the movement of water is driven by the gravitational pull of the Moon.

10. Pros & Cons of hydroelectric At least write these two…

11. The energy of the Sun can be captured directly Geographic variation in solar radiation in the United States. This map shows the amount of solar energy available to a flat photovoltaic solar panel in kilowatt-hours per square meter per day, averaged over a year. The sun delivers more energy to Earth in one hour than humanity consumes over the course of a year! 2009 MIT Technology Review

12. The Sun’s energy can be captured directly “Active” solar energy capturing the energy of sunlight with the use of a pump or photovoltaic cell and generating electricity. The image to the right is not electric solar panels. They are mirrors reflecting sunlight (like a giant magnifying glass) to the tower where water boils, producing steam which spins a turbine, generating electricity – similar to other power plants.

13. Pros & Cons of active solar At least write one pro & one con

14. The Sun’s energy can be captured directly …and in-directly Passive Solar Energy Using passivesolar energy can lower your electricity bill without the need for pumps or other mechanical devices. • Example: building the house with windows along a south-facing wall which allows the Sun’s rays to warm the house in the Winter. Thermal mass A property of a building material that allows it to maintain heat or cold.

15. Earth’s internal heat produces geothermal energy Geothermal energy using the heat from natural radioactive decay of elements deep within Earth as well as heat coming from magma near the surface. Ground source heat pump A technology that transfers heat from the ground to a building. By exchanging heat with the ground, a ground source heat pump can heat and cool a building using 30-70% less energy than traditional furnaces and air conditioners.

16. Wind energy is the most rapidly growing source of electricity • Wind energy- using a wind turbine to convert kinetic energy into electrical energy. • wind turns the wind turbine blade • the gear box transfers mechanical energy to the generator • generator converts mechanical energy into electrical energy • electricity is transferred to the grid

17. Pros & Cons of wind energy At least write one pro & one con

18. Wind Energy • Installed wind energy capacity by country. • China generates more electricity from wind energy than any other country. • However, some relatively small countries such as Denmark, generate a much higher percentage of their electricity from wind.

19. Hydrogen fuel cells have many potential applications • Fuel cell- a device that operates like a common battery where electricity is generated by a reaction between two chemicals. Electrolysis The application of an electric current to water molecules to split them into hydrogen and oxygen.

20. Not needed in notes