8.2 World Energy Sources

Madelief Schelvis October 17, 2012

Non-Renewable Energy

-Def: Fuel reserves are being depleted faster than they are being produced -Fossil Fuels and Nuclear Energy Energy Density: Energy/Mass (J/kg) -Choice of fuel is influenced by its energy density: Cost vs. Benefit -Costs of production: accessibility, purification, transportation, etc.

Fossil Fuels

86.4% of world energy consumption -Energy indirectly from the sun -Burned for energy, releasing CO2 gas (~21.3 tonnes per year) Pros: High energy density, efficient, cost effective, easy to find, easy to transport Cons: Pollution, decreasing reserves

Fossil Fuels: Coal

Energy Density: 32.5 MJ/kg -Historically, the most widely used fossil fuel -Largest world source of energy for electricity generation -Largest producer of CO2 -Fastest growing and largest reserves (909 billion tonnes=155 years global energy use) -2010: World coal consumption: 48% China, 19% Asia (excl. China), 19% North America, 8% EU

Fossil Fuels: Oil

Energy Density: 41.9 MJ/kg -Easier to extract than coal -Estimated 57 ZJ (x10^21 J) oil reserves left on earth -Oil production is estimated to peak in 2020

Nuclear Energy: Fission

Energy Density: 9x10^7 MJ/kg Pros: Little pollution, extremely high energy density Cons: Meltdowns, radiation, dangerous waste that is difficult to dispose of (200 500 year degradation), expensive plant construction and operation -Estimated remaining uranium resources 2500 ZJ

Nuclear Energy: Fusion

Energy Density: 3x10^8 MJ/kg -Vast energy production with very little pollution -Currently only in the sun and other stars -Temperatures and pressures needed to sustain fusion are difficult to produce and control -US, EU, and other countries are supporting fusion research

Renewable Energy

-Inexhaustible energy sources -Solar, wind, waves and tides, hydroelectric, geothermal, biomass -Most of earth's energy sources are renewable; could supply world's energy needs -about 16% world energy use

Renewable Energy: Solar

89 PW (x10^15 Watts) reaches earth from the sun. <0.02% of this is enough to supply world energy needs -Fastest growing source of energy (35% growth over past few years) Cons: Expensive solar cells, reliance on weather patterns, seasons, daytime -Solutions: buying power from equator countries, energy storage (still being researched)

Renewable Energy: Wind

-Energy indirectly from the sun -Available wind energy estimates: 300 TW to 870 TW (x10^12 W) -5% meet world energy needs -Most is available over open ocean (71% of earth's surface) -Denmark 20% energy from wind Pros: Clean, inexpensive to produce, abundant Cons: Wind is inconsistent, turbines are noisy and (some think) ugly

Renewable Energy: Wave and Tidal

Wave: Energy indirectly from the sun Tidal: Energy from gravitational pulls between earth, moon, and sun Tidal forces dissipate earth's rotational energy at the rate of 3.7 TW. Available tidal energy is 20% of this to prevent disturbances.

Pros: Reliable, predictable, no emission, efficient Cons: Expensive, location-specific, restrict water flow, environmental issues

Renewable Energy: Hydroelectric

-Energy indirectly from the sun -Most widely used source of renewable energy -In 2005, hydroelectric power supplied 16.4% of world electricity -Pros: reliable, consistent, clean, low operation cost -Cons: dam creation, need altitude, problems with drought, silt

World Energy Sources

Question: Identify the following energy sources as renewable or nonrenewable.

-Fossil Fuels (Coal, Oil) -Nuclear Energy -Solar -Wind -Wave and Tidal -Hydroelectric

Answer: Renewable and Nonrenewable

-Fossil Fuels (Coal, Oil) -Nuclear Energy -Solar -Wind -Wave and Tidal -Hydroelectric

Bibliography

http://en.wikipedia.org/wiki/World_energy_resources http://en.wikipedia.org/wiki/Fossil_fuel http://vimeo.com/36495727 http://www.scribd.com/doc/13750977/39/World-Energy-Sources http://en.wikipedia.org/wiki/World_energy_consumption http://www.alternativeenergysecret.com/fossil-fuels.html

http://en.wikipedia.org/wiki/Peak_oil http://members.tripod.com/funk_phenomenon/nuclear/procon.htm

http://www.triplepundit.com/2012/06/wind-power-pros-cons/ http://www.buzzle.com/articles/hydroelectricity-pros-and-cons.html