Bellwork 3/22/12 Define: Elevation, Flow Rate, Fluid, Fluid Dynamics, Force, Hydrodynamics, Pressure

Evaluating Energy Resources Renewable Future availability Net energy yield It takes energy to get energy Habitat degradation Cost (initial and ongoing) Community disruption Political or international issues Suitability in different locations Polluting (air, water, noise, visual)

Important Nonrenewable Energy Sources

What are the fossil fuels? What percentage of the world’s energy is fossil fuels? Which do we use for electricity?

FOSSIL FUELS 85% of the world’s commercial energy COAL How are fossil fuels formed? NATURAL GAS OIL

20 richest countries consume: 50% of coal 80% of natural gas 65% of oil How are fossil fuels formed?

North American Energy Resources US has only 2.4% of world’s oil reserves How are fossil fuels formed? Average American uses in one day what a person in the poorest countries use in one year

COAL Fossilized, condensed carbon-rich fuel 10 X reserves of oil/gas, last 200 years at present rate

Coal – What is it? Solid fossil fuel formed in several stages Land plants that lived 300-400 million years ago Subjected to intense heat and pressure over many millions of years Mostly carbon, small amounts of sulfur

Coal Formation and Types

Coal – what do we use it for? Stages of coal formation 300 million year old forests peat > lignite > bituminous > anthracite Primarily strip-mined Used mostly for generating electricity Used to generate 62% of the world’s electricity Used to generate 52% of the U.S. electricity Enough coal for about 200-1000 years U.S. has 25% of world’s reserves High environmental impact Coal gasification and liquefaction

Coal: Trade-offs World’s most abundant fossil fuel Mining and burning coal has a severe environmental impact Accounts for over 1/3 of the world’s CO2 emissions

Discussion Questions? How is your classroom lit? Where does the electricity come from to power the lightbulbs in your classroom? How much do you think it costs to light your classroom for one hour?

Calculating Costs The electricity needed for the fluorescent tubes used to light most classrooms costs approximately three-tenths of a cent per hour. Can you figure out how much it would cost to light our classroom for 1 hour? N x 0.003 = Cost/hour How much would it cost for the entire day? Week? Year?

Coal Costs It takes approximately 1 ton of coal to produce 2,500 kilowatthours (kWh) of electricity (or 1 pound of coal to produce 1.25 kilowatt-hours) The average fluorescent tube uses 18 watts per hour or .018 kilowatt-hours of power per bulb. How much coal do we use in 1 hour to light the school? 1 week? 1 year?