Fossil Fuels Non-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-19 th 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 CO 2 drives global warming More than CO 2 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 O 2 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 ) 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