1. Renewable Energy and Conservation
Chapter 13

2. Renewable Energy Resources
Biomass
Hydroelectric power
Geothermal
Solar—passive and active
Wind generation
Hydrogen power

3. Array of solar panels in rural Kenya
Array of solar panels in rural Kenya. Silicon photovoltaic panels can be made of crystalline or amorphous silicon.
Crystalline one is more efficient-that is it can convert a larger fraction of solar energy to electricity. Amorphous silicon is less efficient, costs far less to produce. The panels shown here convert solar energy to electricity, which can be stored in a battery and used to run a small appliance.

4. Overview of Chapter 13 Direct Solar Energy Indirect Solar Energy
Heating Buildings and Water
Solar Thermal Electric Generation
Photovoltaic Solar Cells
Indirect Solar Energy
Biomass Energy
Wind Energy
Hydropower
Other Renewable Energy Sources
Geothermal Energy
Tidal Energy
High and Low Technology Energy Solution
Hydrogen and Fuel Cells
Energy Efficiency

5. Direct Solar Energy
Varies with latitude, season, time of day, and cloud cover
Areas at lower latitudes-closer to the equator receive more solar radiation annually
Than do latitudes closer to the North and South Poles.
More sun is received during summer than during winter because the sun is directly
overhead in the summer and lower on the horizon in winter. Solar radiation is more
Intense when the sun is high in the sky (noon) than when it is low in the sky (dawn or
Dusk)
Clouds scatter incident light and
Absorb some of the sun’s energy,
Thereby reducing its intensity.
The South Western U.S, with its
Lack of cloud cover and lower
Latitude, receive the greatest amount
Of solar radiation annually
Whereas the Northeast receives
The least.

6. Solar Cookers
O.5 million people in rural areas of Africa, Central America, India, and china are currently using solar cookers. Solar cookers transmit solar light into the cooker, and the glass cover does not transmit the infrared wavelengths
(heat) that would normally escape our of the cooker. pots containing food are placed inside the box on a black metal
Plate. The solar cooker can reach a
Temperature of 177 ̊C and can boil,
Bake, and saute foods. In average
Sunlight, a person can cook a full meal
In two to four hours.

7. Heating Buildings and Water
Passive solar energy
system of putting the sun’s energy to use without requiring mechanical devices to distribute the collected heat
Certain design features can enhance passive solar energy’s heating potential
South facing windows (in N. hemisphere)
Well insulated buildings
Attic vents
Overhangs and solar sunspaces
it costs bit more initially than do traditional designs homes.

8. Several passive designs are incorporated into this home.

9. Solar sunspace Utilizes passive solar energy to heat and cool homes
Can be added to existing homes

10. Heating Buildings and Water
Active Solar Energy
System of collecting and absorbing the sun’s energy, and using pumps or fans distribute the collected heat
Most common
Series of collection devices on roofs or in fields
Typically a black panel or plate
Used to heat water

11. Heating Buildings and Water
Solar Thermal Electric Generation
Means of producing electricity in which the sun’s energy is concentrated by mirrors or lenses to either heat a fluid filled pipe or drive a Stirling engine
More efficient than other solar technologies
Benefits
No air pollution
No contribution to global warming or acid precipitation

12. Solar Thermal Electric Generation
Refer page number
The world’s largest solar thermal
System is currently operating in
The Mojave Desert in Southern
California.

13. Photovoltaic Solar Cells
A wafer or thin film of solid state materials, such as silicon or gallium arsenide, that is treated with certain metals, so that they generate electricity-that is flow of electrons-when they absorb solar energy.
Convert sunlight directly into energy
No pollution and minimal maintenance
Used on any scale
Lighted road signs
Entire buildings

14. Photovoltaic Solar Cells
Can be incorporated into building materials
Roofing shingles
Tile
Window glass

15. Cost of Electrical Power Plants

16. Indirect Solar Energy Biomass Plant materials used as fuel
Ex: wood, crop wastes, saw dust wood chips algal crops sawdust, and animal wastes
Contains energy from sun via photosynthesizing plants
Renewable when used no faster than it can be produced
Firewood –burned
Animal dung –and peat (partly decayed plant matter)
Can convert to biogas or liquids
Ethanol and methanol

17. Advantages and Disadvantages of Biomass
Reduces dependence on fossil fuels
Often uses waste materials
If trees are planted at same rate biomass is combusted, no net increase in atmospheric CO2
Low levels of sulfur and ash
Disadvantages
Requires land, water and energy
Compete with the growing of food crops
Removal of crop residues would deplete the soil of
minerals
Can lead to
Deforestation
Desertification
Soil erosion
Biogas is mixture of gases mostly methane and is a clean fuel. In U.S it accounts for 3% of total U.S. Energy Production. The solid remains are used as fertilizer. Liquid biomass is ethanol and methanol. Biodiesel made from pant or animal oils.

18. Indirect Solar Energy Wind Energy
Electric or mechanical energy obtained from surface air currents caused by solar warming of air
World’s fastest growing source of energy
Wind results from sun warming the atmosphere
Varies in direction and magnitude
New wind turbines harness wind efficiently
Denmark, one of the world leaders in wind power produces 21% of its electricity using wind energy.

19. Wind Energy No waste- clean source of energy Biggest constraints
Most profitable in rural areas with constant wind (islands, coastal areas, mountain passes, grassland
Few environmental problems
Kills birds and bats
No waste- clean source of energy
Biggest constraints
Cost
Public resistance
Germany currently leads the world as the top producer of wind energy.

20. Indirect Solar Energy Hydropower Sun’s energy drive hydrologic cycle
Form of renewable energy reliant on flowing or falling water to generate mechanical energy or electricity
Sun’s energy drive hydrologic cycle
Most efficient energy source (90%)

21. Hydropower Generates 19% of world’s energy
The potential energy of water held back by a dam is converted to kinetic energy as the water falls down and turns turbines to generate electricity.
It is the most widely used forms of solar energy.
New technology
May be able to utilize low flow waterways
Refer to table 13.2: Advantages and Disadvantages of Dams
The three Gorges Dam in China on the Yangze river and its impact

22. Impacts of Dams
Changes natural flow of rivers
A dam causes water to back up, flooding large areas of land and forming a reservoir, which destroys plant and animal habitats.
Native fishes are susceptible to dams because the original river ecosystems is altered.
Disrupts migratory fish patterns
Potential dam breaks
Natural beauty of the countryside is affected, and certain forms of wilderness recreation ar made impossible.
Reservoir induced seismicity.
Greater water loss by evaporation resulting in increased salinity.
Schistosomiasis, which damage the liver, urinary tract, and lungs may spread. (Egypt due to Aswan Dam built on the Nile River)
Wild and Scenic Rivers Act prevents the hydroelectric development of certain rivers.
A dam has a limited life span for years. It traps silt which affects agricultural lands downstream.

23. Other Indirect Solar Energy
Ocean waves
Produced by winds
Has potential to turn a turbine- and create electricity
Ocean Temperature Gradients
Use difference in temperature of surface and deep water to create electricity. Ocean Thermal Energy Conversion (OTEC) would take advantage of the temperature difference between the warm surface water and the cold deep waters to produce electricity or to cool buildings.
The first commercial OTEC plant is under construction at the National Energy Laboratory of Hawaii Authority on the Island of Hawaii.

24. Geothermal Energy From hot, dry rock Geothermal heat pumps
Use difference in temperature between surface and subsurface
Great for heating buildings
Expensive installation

25. Geothermal energy
Steam separated from hot water pumped from underground turns a turbine and generates electricity. After its use steam is condensed and pumped back into the ground. By reinjecting spent water into the ground, geothermal energy remains a
renewable energy
source because the
cooler reinjected water
can be reheated and
used again.

26. Geothermal energy
The United States is the world’s largest producer of geothermal energy. California, Nevada, Utah, and Hawaii.
The world’s largest geothermal power plant is The Geysers, a geothermal field in northern California.
Geothermal plants are also there in Philipines, Italy, Japan, Mexico, Indonesia, and Iceland.
Geothermal energy emits hydrogen sulfide
Surrounding lands may subside or sink as the water from the hotspring and underground water is removed.

27. Heating and cooling buildings with geothermal energy.
Geothermal Heat Pumps (GHPs) take advantage of the difference in temperature between Earth’s surface and subsurface.
Installation of GHPs can beexpensive.
Benefits.
Low operating costs.
Efficient heating system
Lowest carbon dioxide emissions

28. Tidal Energy
Tides, the alternate rising and falling of the surface waters of the ocean and seas that generally occur twice each day, are the result of gravitational pull of the moon and sun.
The difference in water level between high and low tides is about 0.5 m. Certain coastal regions with narrow bays have extremely large differences in water between high and low tides.
The Bay of Fundy in Nova Scotia has the largest tides in the world, with 16m difference between high and low tide.
Water at high tide contain enormous potential energy compared to low tide. This energy can be captured and converted into electricity.
Location of tidal power plants: France, Russia, china, and Canada.

29. Energy conservation and Energy Efficiency
Energy conservation: Using less energy, as for example, by reducing energy use and waste. This would include carpooling and lowring driving speeds.
Energy efficiency: Using less energy to accomplish a given task, as for example with new technology.
Both achieve same goal: Saving Energy
Reduce air pollution, acid precipitation.
Read A starring role in Energy Efficiency

30. Hydrogen as a Fuel Source
Advantages to Hydrogen as a fuel source
Very high energy density
Can be produced from any electrical source
Electrolysis (see illustration on next slide)
No greenhouse gases and few other pollutants
Can be use in vehicles
Disadvantages to Hydrogen as a fuel source
Highly volatile (requires special storage)
Relatively inefficient (much of electricity is wasted in production of Hydrogen)

31. Hydrogen as a Fuel Source- Electrolysis

32. Hydrogen Fuel Cell Fuel cell
Device that directly converts chemical energy into electricity
Requires hydrogen from a tank and oxygen from the air
Similar to a battery, only the reactants are supplied from outside source

33. Future Applications of Fuel Cells
Vehicles
Not yet commonly available
Hydrogen is not yet readily available as a fuel source
Batteries in cells phones or laptops
Iceland plans to build the world’s first fleet of fuel cell buses, obtaining its hydrogen from geothermal and hydroelectric resources.

34. Energy Consumption Trends and Economics
A country’s total energy consumption per unit of its gross domestic product in purchasing power parity (GDP PPP) gives one measure of its energy intensity. Lower energy intensity means that the economy is more energy efficient and does not mean a lower standard of living.

35. Energy-Efficient Technologies
The National Appliance Energy conservation Act (NAECA) sets national efficiency standards fro refrigerators, freezers, washing machines, clothes dryers, dish washers, room air conditioners, and ovens.

36. Energy Efficient Technologies
Compact Fluorescent light bulbs
Condensing furnaces
Super-insulated buildings (right)
Energy efficient appliances
Automobiles
Aircraft technology

37. A Superinsulated office building in Toronto, Canada
It has south facing windows with insulating glass. The building is so well insulated that it uses no furnace.

38. Cogeneration
Production of two useful forms of energy from the same fuel

39. Energy Savings in Commercial Buildings

40. What does this cartoon imply about the relevance of energy efficiency in automobile purchasing decisions? Do you think attitudes will change? Why/why not?

41. You can Make a Difference Very important
Read page number 304 in your Text Book.