fossil fuels non-renewable energy. sources of energy sun’s radiation biomass – wood fossil fuels...
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Fossil FuelsNon-renewable Energy
Sources of Energy
• Sun’s radiation• Biomass – wood• Fossil fuels formed from remains of past
organisms• Wind and hydroelectric (sun is ultimate source)• Geothermal• Tidal power• Chemical (bonds)
Sources of Energy
• Perpetually renewable: solar, geothermal, wind, tidal
• Renewable: timber• Nonrenewable: coal, oil , natural gas• Net energy expresses the difference between
returned and invested energy• Fossil fuels: formed from organisms of 100 –
500 MYA
Sources of Energy
• Most organisms that die undergo aerobic decay: matter is recycled
• Fossil fuels produced by anaerobic decay• Unevenly distributed
COAL
Coal
• Organic matter compressed under high pressure forming dense, solid carbon structures
• Coal use has a long history• Peat: precursor to coal• Classified as lignite, sub-bituminous,
bituminous, anthracite; anthracite is most energy-rich
Coal
• Impurities in coal include S, Hg, As and other metals
• Coal can be mined subsurface or surface
NATURAL GAS
Natural Gas
• Much cleaner-burning fuel than coal or oil• Natural Gas is primarily methane• Formed in 2 ways:– Thermogenic gas (deep, from geothermal) aka
coalbed methane– Biogenic gas created at shallow depths from
anaerobic decay of organic matter (bacteria); new tech: landfill capture
Natural Gas
• Only recently widely used (1950’s saw pipeline development)
• To access deposits, a drilled opening will allow gas to surface (pressure gradient)
• Most fields today require pumping• Offshore drilling produces much of our gas and
oil
OIL
Oil
• Heat and pressure underground form petroleum, aka crude oil (1.5 – 3 km below sfc)
• Age of oil began mid-19th century• Petroleum geologists infer the location and size
of deposits• Some portion of oil will be impossible to
extract using current technology• Technology sets a limit on amount extracted:
proven recoverable reserve
Oil
• Extraction: drilling• Begins with exploratory drilling• Oil in rocks typically under pressure• Primary extraction – removes about 1/3 of
total (initial drilling and pumping)• Secondary extraction –uses solvents, or
water/steam to flush the crude; expensive
Oil
• We may have depleted half our oil reserves• At current levels of production 40 years worth
remain• However as production declines and demand
increases, a crisis may occur in the next several years
• Industrialization of China and India are increasing the demand
ENVIRONMENTAL IMPACTS
Emissions
• Air pollution and climate change• CO2 drives global warming
• More than CO2 is released – serious consequences for environment and human health
Coal Mining
• Surface strip: habitat destruction and soil erosion
• Acid drainage occurs when sulfide minerals are exposed to water and O2
• Metal leaching• Inexpensive due to gov’t subsidies
Oil and Gas Extraction
• Drilling is minimal, but development process involves more
• Fragmentation of habitats• Extensive infrastructure: housing, access roads,
pipelines, waste piles• Arctic or semi-arid areas are sensitive
POLITICAL AND SOCIO-ECONOMIC IMPACTS
Dependence
• Economies tied to fossil fuels are vulnerable• In US – concern over reliance on foreign oil
puts pressure to open ANWR to drilling• US has also diversified sources• Oil supply and prices impact economies (crisis
of 1973-74)• Residents may not benefit from their fossil fuel
reserves (1958, Nigeria, Shell oil extracted $30 billion in oil; poverty is still rampant)
Converting to Renewable Energy
• One option – commit to using fossil fuels and develop alternative energies after depletion
• Second option – fund development of alternative energy sources now and attempt to reduce reliance on fossil fuels slowly
• Third option – end fossil fuel use quickly and hasten renewables
CONSERVATION
Conservation
• Conservation has followed economic need• Many of the policies developed after the 1973
crisis have been abandoned• Lack of motivation with no immediate threat• US – low taxes on gasoline• Personal choice and increased efficiency are
two routes to conservation• Cogeneration – using excess heat to power
other devices
Conservation
• Both conservation and renewable energy are needed
• Reduce energy usage to extend the lifetimes of reserves
• Rapid development of renewable resources