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