ENERGY ALTERNATE ENERGY SOURCES Solar Energy Definition Of

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/cm 2 – 1010 watts/0. 024 watts/cm 2) = 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 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 2000 MW 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 1 D 2 into 2 He 3 or 2 He 4 – 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 1 H 1 – Deuterium 1 D 2 – Tritium 1 T 3

Atomic Fusion • The Reactions – 2 + D 2 --> He 3 + n + 3. 2 M 106 electron D 1 1 2 ev volts) • This produces a stable end product – 2 + D 2 --> T 3 + H + 4. 0 Mev D 1 1 1 • 1 T 3 is unstable and reacts with 1 D 2 – 1 D + 1 T 3 --> 2 He 4 + n + 17. 6 Mev – Total energy released is 5 1 D 2 --> 2 He 4 + 2 He 3 + H + 2 n + 24. 8 Mev 2

Atomic Fusion • How Much Resource is Available? – There is 1 1 D 2 atom per 6, 500 H atoms in sea water – One cubic meter of sea water contains 34. 4 grams 1 D 2 • 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