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ENERGY
ALTERNATE ENERGY SOURCES
Solar Energy
• Definition Of Solar Energy
– This is energy received from the sun by the Earth in the
last 100 years
• Hydroelectric power
• Wind power
– PG & E
83 MW by 1990
– SCE
43 MW by 1990
• Wood
• Ocean currents
• Passive and direct solar power
Solar Energy
• Advantages of Solar Power
– Solar energy received by the Earth is enormous 17.7 x
1016 watts
• 100,000 x world electrical output
–
–
–
–
–
Infinite supply
Constant supply
No pollution
No boycotts
Biologically compatible
Solar Energy
• Passive Solar Power
– Space heating
– Water heating
Solar Energy
• Direct Solar - Converts Sunlight to Electricity
– This is very expensive
– Modern 1000 MW plant would require 42 sq. km. or
16.2 sq. miles
• 10,000 MW input
• Surface receives 0.024 watts/cm2
– 1010 watts/0.024 watts/cm2) = 42 sq. km.
– A future approach might involve satellite receivers
microwaving the energy to Earth
Water Power
• History and Potential
– Large scale generation and transmission of
water power started around 1900
– Present production is 45,000 MW
• Ultimate maximum based on stream flow is 161,000
MW
• It appears that some used potential may help
compensate for declining fossil fuels
Water Power
• The Problems of Hydroelectric Power
– Dams have a large impact on the environment
– Most acceptable hydro sites are already
developed
– Hydroelectric power only supplies a small
percent of the nations power
Tidal Power
• Same Basic Principle as Hydroelectric
Power
• Tidal energy can be exploited in two ways:
– By building semi-permeable undersea tidal
turbines across estuaries with a high tidal range.
– By harnessing offshore tidal streams
Tidal Power
• How it works:
– Water flow as basin fills or
empties drives turbines
– Similar to a wind turbine,
but goes in both directions
– Requires a daily tidal range
of 5-7 meters (~15-21 feet)
to be practical
– Characterized by low
capacity factors, usually in
the range of 20-35%.
Tidal Power
• Locations
– 240 MW facility has operated in France since
1966
– 20 MW in Canada since 1984
– A number of stations in China since 1977,
totaling 5 MW
List of World Main Tidal
Power Stations
Country
Power Station
Tidal Loss (m)
Capacity (MW)
Operated Since
France
Langce
8.5
240
1966
Canada
Andeboriece
7.1
19.1
1984
Former Soviet
Union
China
Gicelaya
3.9
0.4
1968
Jiangxia
5.1
3.2
1980
China
Baishakou
2.4
0.64
1978
China
Xingfuyang
4.5
1.28
1989
China
Yuepu
3.6
0.15
1971
China
Haishan
4.9
0.15
1975
China
Shashan
5.1
0.04
1961
China
Liuhe
2.1
0.15
1976
China
Guozishan
2.5
0.04
1977
Tidal Power
• La Rance, France - world's first tidal power
plant
– Average tidal range 27 feet
– Dam encloses 8.5 sq. miles
– Capacity is 320,000 KW
Tidal Power
• Low Production but also Low
Environmental Impact
– No noxious waste
– No consumption of resources
– Minimum disturbance to scenery
Geothermal Power
• Source of the Energy
– Conduction to the surface
– Convection by volcanoes and hot springs
Geothermal Power
• Two Methods of Recovery
– Dry Steam Geothermal Fields
• Steam rises to the surface and is used directly to
drive a turbine
• Geysers, California is an example
– Produced 2000MW by 1986
– Serves 12 cities & 2 million people around
Sonoma County
– Ultimate possible is 2500 MW
– This type is rare
Geothermal Power
• Two Methods of Recovery (continued)
– Wet Steam Geothermal Power
• Steam and water come to the surface and must be separated
• This type is found and used in New Zealand, Japan, Mexico,
Russia, & Iceland
• Water may be used for conventional heating before disposal
• Disposal method depends on salinity
– Pour it into a river
– Pipe it to the ocean for disposal
– Reinject it
Geothermal Power
• Recovery from Non-thermal Areas
– This is more challenging and has not yet been
accomplished
– Drill 2 adjacent holes
• Pump cold water into one
• Recover steam from the other
Atomic Fusion
• Possibility was first recognized by Hans
Bethe 1939 - Nobel Prize)
– Concept is to harness the energy of the sun by
fusing 1D2 into 2He3 or 2He4
– This has already been done in the form of the
hydrogen bomb
Atomic Fusion
• Definitions
– Proton – a positively charged subatomic particle
– Neutron – a negatively charged subatomic particle
Atomic Fusion
• Definitions
– Isotope – atom that exhibits variation in its
mass number
– Mass number – sum of the neutrons plus the
protons in an atom
– Atomic number – # of protons found in the
nucleus
– Atomic weight – average of the atomic masses
of all the element's isotopes
Atomic Fusion
• Definitions
– Fission – the act or process of splitting into
parts
– Fusion – a nuclear reaction in which nuclei
combine to form more massive nuclei with the
simultaneous release of energy
Atomic Fusion
• The 3 Isotopes of Hydrogen
– Hydrogen 1H1
– Deuterium 1D2
– Tritium 1T3
Atomic Fusion
• The Reactions
– 1D2 + 1D2 --> 2He3 + n + 3.2 Mev 106 electron
volts)
• This produces a stable end product
– 1D2 + 1D2 --> 1T3 + H + 4.0 Mev
• 1T3 is unstable and reacts with 1D2
– 1D2 + 1T3 --> 2He4 + n + 17.6 Mev
– Total energy released is 5 1D2 --> 2He4 + 2He3 +
H + 2n + 24.8 Mev
Atomic Fusion
• How Much Resource is Available?
– There is 1 1D2 atom per 6,500 H atoms in sea
water
– One cubic meter of sea water contains 34.4
grams 1D2
• Potential energy equals 269 metric tons of coal or
1,360 barrels of oil
– One cubic km of sea water equals 269 billion
tons of coal or 1,360 billion bbls oil
• Exceeds the entire world oil resource