1. Energy II: Renewable Energy
THE GOOD NEWS

2. Energy Resources Renewable (Alternative) Energy: Nonrenewable Energy:
Alternative energy sources that are more or less continuously made available in a time framework useful to humans
Nonrenewable Energy:
Energy sources that are dependent upon fuels or a resource that that may be used up much faster than it is replaced by natural processes

3. Current Sources of Energy

4. Current Costs of Energy

5. Types of Renewable Energy
Solar
Water
Wind
Biomass
burning
conversion to liquid fuels
Geothermal
Solar-Hydrogen

6. Solar Energy Used to Heat houses and buildings Heat water
Create high temperature heat
Create electricity

7. Passive Solar Building Heating
Architectural Design
exposure direction, windows, building materials, eaves
Requires no energy to use

8. Active Solar Building Heating
Uses mechanical power and pumps to circulate air
A heat absorbing fluid is heated in the sun and then transported into the structure

9. Water Heating Flat-plate collectors -
flat box with glass on top, black on the bottom, water tubes in middle
hot water coming out of tubes is placed in top of tank
cooler water from bottom of tank is returned to collector

10. High Temperature Heating
Solar towers
many solar panels are used to focus solar energy for immediate, or later use
Solar cookers
metal lined box and mirrors focus solar energy to cook food

11. Solar electricity Photovoltaic cells or solar cells
When photons from sunlight hit a thin wafer of metal, a small electric current is produced
many cells must be linked together to produce usable energy
are mostly used in remote areas, calculators, watches

12. Locations in U.S. with good solar potential

13. Water Power Methods of creating electricity dams tides waves
solar ponds
OTEC

14. Hydroelectric Power: Dams
High dam is built across a river to make a reservoir
water is allowed through dam, past turbines
spinning turbines produce electricity
20% of world’s energy

15. Problems with hydroelectric power
Damming floods areas above dam, ruining biologically, agriculturally or culturally important areas
migration of fish is disrupted (ex. salmon)
change of cold water stream to warm water lake - increases humidity and temps (new pests?)
Downstream areas are affected because of lack of floods, unpredictable water levels, cold water from bottom of dam

16. Tides
In places in the world where there are extreme tides, electricity can be generated from tides
Water can be held back, and let through turbines like in dams
If turbines work in both directions, energy can be generated 2 times a day

17. Waves In some locations in the world, waves are consistent and strong
In these places, electricity can be generated from waves
probably not going to be a major source of global electricity

18. Solar Ponds
In inland saline seas, heat accumulates in the saltier bottom layer. As it heats up, this layer is pumped out and used for heating or electricity.
In fresh water ponds, holes are dug and lined with black. The water heats up, but the heat is prevented from escaping
Both of these are cheap and do not pollute. They don’t require expensive storage. Some energy.

19. OTEC: Ocean thermal energy conversion
In tropical waters there is a large difference between the surface and bottom temperature
The heat at the surface is used to vaporize a low boiling point liquid
The pressure is used to run turbogenerators
Liquid is condensed using bottom water
Not very useful

20. Wind Power Wind power is created by wind turbines
Wind Farms - location of high wind where many turbines are concentrated (ex. Palm Springs)
Problem : requires expensive storage during non-windy periods, hurt birds

22. Biomass - burning Burning of organic material
examples: wood, reeds, animal dung, etc.
Potentially renewable resource - but biomass must not be removed faster than it can be replaced
used primarily in developing countries
trash can also be burned
can be quite efficient when harvested locally
burning dung takes nutrients from fields

23. Biomass - burning

24. Biomass- conversion to liquid biofuels
Methane
Animal dung can be digested by bacteria and converted to methane
Burning methane provides more energy than burning dung
Currently practiced on a small scale/has potential
Ethanol and methanol
excess grain stocks can be fermented by bacteria to produce these fuels which can then be burned as fuel
Burning both of these fuels still produces CO2

25. Geothermal Energy
In some places on the Earth’s surface, the hot magma beneath the surface produces hot springs and geysers
At these locations, hot pressurized steam can be brought to the surface to turn turbines
The steam is then condensed and returned to the earth

26. Solar-Hydrogen Energy- Theory
Hydrogen gas can be used for energy in two ways:
burned directly - since no carbon, it burns cleanly, producing water
combined with oxygen gas to produce water (fuel cells)

27. Solar-Hydrogen Energy
Problem:
Hydrogen gas is very rare in the environment
H2 gas is costly to make through chemical reactions
Solution
H2 and O2 can be produced easily by running a current through water - electrolysis
Solar cells can be used to create electricity to fuel electrolysis H2 gas

28. The Negawatt Revolution
In the past, electrical companies have increased their profits by increasing demand, and building more plants
Now it is cheaper for them to encourage users to lower their own energy needs to reduce the need for expensive plants
So energy companies now give incentives to people who employ energy saving strategies

29. Energy Deregulation
California is currently in the process of energy deregulation
Impacts on rates
Impact of energy sources used
Will it work?

30. All you wanted to know about these energy sources and their benefits and drawbacks
Miller p