Fossil Fuels

Energy Use• 85% nonrenewable

energy• Use of coal • Use of oil• Nuclear has leveled off• Developing countries:

depend on biomass (fuelwood, charcoal) for heating/cooking– Can’t afford fossil

fuels!!!!

• 93% Nonrenewable• World’s largest energy

user• 5% of world’s

population uses 25% of world’s energy

World U.S.

What are fossil fuels???

• Composed of partially decayed organism remains

• Form too slowly to replenish

• NOT sustainable• Ex: Coal, Oil, Natural

Gas

Fossil Fuels

• Oil, Natural Gas & Coal• Oil and Natural Gas are

less dense than coal– Move upward through

porous rock and become trapped

• Developed countries (like US!) consume 8X MORE energy than developing countries

Formation of Fossil Fuels

• Formation of coal– Over time, plants die

and get covered by water and sediment

– Heat & pressure convert material into carbon rich ore (COAL) & sedimentary rock

• Formation of Oil– Death of plants/animals:

go through decomposition

– Heat & pressure convert material to hydrocarbons (OIL) without oxygen in sediments that prevent decay

Formation of Fossil Fuels

• Formation of Natural Gas– Same as oil, just produced at higher temperatures

2008: Energy Use in the US

• Comprised of– Oil 40%– Natural Gas 23%– Coal 20%– Nuclear Power 8%– Hydropower 3%– Biomass 3%– Geothermal, Solar & Wind 1%

We depend heavily on oil…

• You know it as:– Petroleum and crude oil

• Composed of various hydrocarbons

• Produced by decomposition of dead organic matter from plants/animals

• We import at least 52% of our oil

Oil Supplies• Proven oil reserves

– Identified deposits that can be extracted profitably with current technology

• Unproven reserves– Probable reserves: 50%

chance of recovery– Possible reserves: 10-40%

chance of recovery

• Proven and unproven reserves will be 80% depleted sometime between 2050 and 2100

• 13 countries have at least 60% of the world’s crude oil reserves

• Global oil production leveled off in 2005

Coal

• Solid fossil fuel• Burned in power plants

(inefficient)• World’s most abundant

fossil fuel

• Different steps of formation:– Peat: not a coal– Lignite: brown coal– Bituminous: soft coal– Anthracite: hard coal

Advantages and Disadvantages of Using Coal

• Advantages:– Plentiful– High net energy yield– Low cost

• Disadvantages:– Very high environmental

impact– Severe air pollution

• Sulfur released as SO2

• Large amount of soot• CO2

• Trace amount of Hg and radioactive materials

Natural Gas

• Mixture of gases• 50-90% methane (Ch4)• Versatile with high net

energy– Heat space & water– Produce electricity

• More plentiful than oil• Fairly low cost• Issue of fracking (will

examine in video)

Conventional Natural Gas VS Fracking

• Conventional Natural Gas– Lies above most

reservoirs of crude oil– Makes US dependent

upon unstable countries like Russia and Iran

• Fracking:– Official term: Hydraulic

fracturing– Extraction from shale

rocks using a combination of vertical and horizontal drilling

– Water and other chemicals used to “fracture” rocks and release gas

– Michigan sits on deposits of shale