1. Renewable Electricity

2. Using Solar Energy to Generate High-Temperature Heat and Electricity
Solar Concentrators
Deserts
Mirrors can focus sunlight to heat up an oil or molten salt which is used to boil water
Construction costs are high
Some birds mistake the mirrors for water

3. Producing Electricity with Solar Cells
Photovoltaic (PV) cells can provide electricity for a house of building using solar energy roof shingles.
Video
Solar cells can be used in rural villages with ample sunlight who are not connected to an electrical grid to do a lot.

4. Where Can We Use Solar?
This map shows the amount of solar energy in hours, received each day on an optimally tilted surface during the worst month of the year.
This map shows the amount of solar energy in hours, received each day on an optimally tilted surface during the worst month of the year

5. PRODUCING ELECTRICITY FROM WIND
Wind power is the world’s most promising energy resource because:
it is abundant
renewable
cheap
clean, emits no greenhouse gases
Wind turbines can be used individually to produce electricity.
Many wind turbines
make up a wind farm.

6. ELECTRICITY FROM WIND
The United States once led the wind power industry, but Europe now leads this rapidly growing business. Why?
The U.S. government lacked subsidies, tax breaks and other financial incentives.
Which country was the first to use wind turbines to produce commercial electricity in 1890?
Denmark

7. GEOTHERMAL ENERGY
Geothermal energy consists of heat stored in soil, underground rocks, and fluids in the earth’s mantle.
Can heat and cool buildings
Can produce electricity
What is magma?
Video

8. Largest group of Geothermal Power plants in the World?
The country that is the world's largest producer of geothermal electricity is _____
Second Place (first loser): Philippines
Largest group of Geothermal Power plants in the World?
The Geysers in Northern California
A complex of 22 geothermal power plants located in the Mayacamas Mountains 72 mi north of San Francisco. The Geysers has an average production of 955 MW
USA!!!

9. Generating Geothermal Electricity
Dry Steam Power Plants:
Underground steam is piped directly from the ground to the generators. (example: The Geysers)
Dry steam: water vapor with no water droplets. (only 2 sources in USA)
Flash Steam Power Plants
Use geothermal reservoirs of hot water (>360°F) that rises to the surface under its own pressure. (Most common)
Wet steam: a mixture of steam and water droplets.
Binary Cycle Power Plants
Use lower temperature water ( °F) to heat a low boiling point fluid to produce steam
Water is injected back into
ground to be reheated
***Most common new type***

10. DAMS AND RESERVOIRS Pros: Cons: cheap electricity
reduce downstream flooding
provide year-round water for irrigating crops
Cons:
displaces people (floods upstream)
disrupt aquatic sys. –sometimes, the river stops flowing to the ocean, runs out of water
Expensive to build

11. Provides water for year-round irrigation of cropland
Flooded land destroys forests or cropland and displaces people
Large losses of water through evaporation
Provides water for drinking
Downstream cropland and estuaries are deprived of nutrient-rich silt
Reservoir is useful for recreation and fishing
Risk of failure and devastating downstream flooding
Can produce cheap electricity (hydropower)
Figure 14.13
Trade-offs: advantages (green) and disadvantages (orange) of large dams and reservoirs. The world’s 45,000 large dams (higher than 15 meters or 50 feet) capture and store 14% of the world’s runoff, provide water for almost half of all irrigated cropland, and supply more than half the electricity used by 65 countries. The United States has more than 70,000 large and small dams, capable of capturing and storing half of the country’s entire river flow. QUESTION: Which single advantage and which single disadvantage do you think are the most important?
Downstream flooding is reduced
Migration and spawning of some fish are disrupted
Fig a, p. 317

12. Powerlines
Reservoir
Dam
Powerhouse
Intake
Turbine
Figure 14.13
Trade-offs: advantages (green) and disadvantages (orange) of large dams and reservoirs. The world’s 45,000 large dams (higher than 15 meters or 50 feet) capture and store 14% of the world’s runoff, provide water for almost half of all irrigated cropland, and supply more than half the electricity used by 65 countries. The United States has more than 70,000 large and small dams, capable of capturing and storing half of the country’s entire river flow. QUESTION: Which single advantage and which single disadvantage do you think are the most important?
The world’s 45,000 large dams capture and store 14% of the world’s runoff, provide water for almost half of all irrigated cropland, and supply more than half the electricity used by 65 countries.
The United States has more than 70,000 large and small dams, capable of capturing and storing half of the country’s entire river flow.

13. Tidal Power
Tidal Barrage: a dam that at high tide fills up one side with water, low tide release water and spins a turbine.
Bay of Fundy (Nova Scotia)

14. Tidal stream power: under water stream currents spin a turbine.
New York’s east river

15. Comparing Energy Sources
As low as 12 cents now for solar cells

16. Contribution to total energy consumption (percent)
Nuclear
Coal
Natural gas
Oil
Wood
Hydrogen Solar
Contribution to total energy consumption (percent)
Figure 17.34
Science, economics, and politics: shifts in the use of commercial energy resources in the United States since 1800, with projected changes to Shifts from wood to coal and then from coal to oil and natural gas have each taken about 50–75 years. Note that, since 1800, the United States has shifted from wood to coal to oil for its primary energy resource. A shift by 2100 to increased use of natural gas, biofuels, hydrogen gas produced mostly by solar cells, and wind is one of many possible scenarios. (Data from U.S. Department of Energy)
Year
Fig , p. 413