Nonrenewable Energy

Energy Concepts Measuring Energy – Energy: Joule, Calorie, BTU, kWh – Power: Watt (W), Horsepower (hp) Thermodynamics – First Law quantity: we will not run out of energy Cannot be created nor destroyed – Second Law Quality: we can run out of useful energy Always degraded to less useful form, usually heat

Energy Consumption: Past, Present, Future Population Global Energy – 99% comes from the sun Inexhaustible; indirectly responsible for other types – Nonrenewable Oil, coal, natural gas (78% commercial energy) Nuclear (6%) – Renewable Wind, solar, hydro, tidal, geothermal

World – Oil & gas highest consumed fuel type – Developing countries burn wood, charcoal US – Self-sufficient until late 1950’s – Consumption outpaced domestic production Average American uses as much fuel in a day as a person in the poorest countries use in a year – By 1994 Imports surpassed domestic oil supply 94% of energy resources in US are nonrenewable – Environmental, political, & economic issues over future energy resources

Present US Energy Use Most energy comes from – Coal – Petroleum – Natural gas – Uranium – Renewables Biomass, geothermal, hydroelectric, solar, wind

Future US Energy Needs Continue to rely on 3 fossil fuels – Petroleum – Natural gas – Coal Most realistic, economical & viable resources – Clean coal – Methane hydrates – Oil shale – Tar sands

Coal 286 million year old organic matter Forms under high temperature & pressure 3 types – Peat, lignite, bituminous, anthracite Peat – low in heat Mined (surface & underground) – US has most recoverable coal in world – 10 trillion tons US – 87% used to power plants 50% of US electricity (residential & industrial) Clean Air Act – 90% reduction in sulfur

Environmental Problems Carbon dioxide Sulfur Ash Clean coal – Gasification to remove sulfur, carbon dioxide

Peat

Lignite/Brown Coal

Subbituminous Coal

Bituminous Coal

Anthracite Coal

Petroleum Decomposition of deeply buried organic matter Sedimentary – sand Extracted by drilling 76% world supply in OPEC nations Uses: fuel, drugs, plastics, transportation Environmental problems – Air pollution – Global warming

Oil Shale Contain Kerogen – Heated in absence of air converts to oil 3 trillion barrels of recoverable oil in shale – 750 billion in US – Wyoming, Utah, Colorado World: Largest reserves in Estonia, Australia, Germany, Israel, Jordan Extracted by surface mining or heating in place

Problems with Oil Shale Net energy yield is moderate Potential problems: – Air pollution – Acid rain – Contributing to global warming

Tar Sands Contain Bitumen – Semi solid; doesn’t “flow” Mined – strip mined – Steamed in place 5% sulfur content Most reserves in Canada & Venezuela Net energy yield – moderate Problems: – Acid rain, air pollution, global warming

Natural Gas Decomposition of organic material High temperature & pressure Conventional sources associated with oil Unconventional sources – Coal beds, tight sands, shale, gas hydrates Flows under pressure into pipeline Can be liquefied (LNG, LPG) 20 trillion cubic feet produced/yr in US – Remainder imported from Canada

Methane Hydrates First found in 1970’s Frozen in place – Perma frost (Arctic) – Beneath sea floor High pressure, low temperature – Several 100’s meters thick – 3000 x volume in atmosphere 1 cubic meter of hydrate yields 164 cubic meters of gas Potential to have as much energy as the world’s fossil fuels combined

Problems Extraction Methods – Commercially viable – Environmentally acceptable Environmental damage to ecosystem – Sea floor, permafrost Pollution