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Energy Resources Renewable vs. Nonrenewable • Renewable Resources – Resources that are naturally replenished or regenerated over a short time span – it is renewed on a human time scale – i.e. Trees, biofuels (?) • Nonrenewable Resources – Resources that are consumed faster than they can be replenished, it is not renewed on a human time scale – i.e. fossil fuels, aluminum, etc. Sources of Energy Sources of Energy • Nonrenewable sources – – – – Petroleum (38%) Coal (22%) Natural Gas (25%) Nuclear (8%) • Renewable sources – – – – – – Hydroelectric (4%) Solar Wind Tidal Geothermal Biofuels Trends in Energy Usage Coal • Organic materials that have escaped oxidation in the carbon cycle. • Plant material that is rapidly buried Coal Ranking & Formation Rank – amount (%) of carbon (C) in coal , heat content 1. Peat (pre coal) – soft brown mass of compressed, largely nondecomposed plant material, ~50% C 2. Lignite – decomposed peat that has been compressed, ~70% C 3. Bituminous coal – burial increases the pressure and temperature on the lignite and causes a conversion, ~80-90% C 4. Anthracite coal – complete metamorphism, >93% C World-wide distribution of coal U.S. Coal Reserves Illinois Coal Reserves Hydrocarbons • Composed of hydrogen and carbon linked together in chains and rings • Natural Gas – simple organic molecules • Crude Oil – complex chains and rings What is the source of oil? • Plankton! 0mm 1mm Hydrocarbon Formation • • • • • • Water borne plankton escape oxidation/decomposition before burial Plankton is deposited in mud (shale) – Source Rock Source rock is overlain by more sediment – increasing the pressure (P) & temperature (T) on the source rock Increase in P & T, breaks down organic debris – Oil forms at 50oC – Methane (natural gas) at 100oC Hydrocarbons migrates upwards (lower density than water) to a reservoir rock (high porosity, high permeability rock) Migration is stopped by either an impermeable rock or a structural trap “Oil Window” • Generation of oil requires a specific temperature range 80 – 160 Co (If above this temperature oil will “burn away”) • Higher temperatures breakdown oil molecules – generate natural gas • Exist in the top most 15-20% of the crust Reservoir Rock • Porosity – amount of open (void) space in a rock, ability of a rock to store a fluid • Permeability – interconnectedness of the void space, ability of rock to transmit a fluid • Reservoir rock – high porosity, high permeability • Cap (seal) rock – low porosity, low permeability Structural Traps • 4 common types – – – – Anticline Trap Salt Dome Fault Trap Angular Unconformity Trap Distribution of Oil and Gas • Found in rocks less than 500 million years old • 85% of oil and gas occur in less than 5% of producing fields • Generally, near Tectonic belts, active in the past 60-70 million years Daily Assignment • Create a concept map that incorporates the following: Oil Coal Plant Material Plankton Folds Faults Sandstone Shale Labels the pathways-transition between the components appropriately Additional items may be included if you feel they help understand the concepts. Nuclear Power - Uranium • • • • • Uranium (U) – used for nuclear power Has a Minimum Concentration Factor > 1000 Source Rock – Igneous U is leached (dissolved) into groundwater Deposit Types – Sandstones that have been enriched with U minerals (groundwater enrichment) – U-bearing minerals in rock fractures – Placer Deposits Geothermal Energy • Temperature increases with depth ~ 3oC/ 100 m • Geothermal energy concentrated where magma is near the surface • Circulation of groundwater allows water to heat up • Hot groundwater drives turbines