Evaluating Energy Resources  Renewable energy  Non-renewable energy  Future availability  Net energy yield  Cost  Environmental effects

Extracting Energy and Mineral Resources  Surface, subsurface mines, wells

Removing Nonrenewable Mineral Resources Surface mining Subsurface mining  Overburden

Points of View  Cornucopians - we will not run out of non-renewable resources because of economics and technology  Cornucopians - we will not run out of non-renewable resources because of economics and technology  Neo-Malthusians - we will run out of non-renewable resources (limited supply) - must control population, conserve  Neo-Malthusians - we will run out of non-renewable resources (limited supply) - must control population, conserve

Supplemental Energy Solar energy - 99% of all energy used Supplemental energy - everything else

History of Supplemental Energy in United States  Wood through mid-1800s -Renewable -Maximum sustained yield limits supply  Wood through mid-1800s -Renewable -Maximum sustained yield limits supply  Coal replaced wood by 1900  Oil, natural gas exploited (since mid-1900s) #1-oil, #2-natural gas, #3-coal - all non-renewable  Oil, natural gas exploited (since mid-1900s) #1-oil, #2-natural gas, #3-coal - all non-renewable  Use growing dramatically

Year Contribution to total energy consumption (percent) Wood Coal Oil Nuclear Hydrogen Solar Natural gas

How long will supplies last?  U.S. (5%) uses 25% of energy  Depends on: - rate of use - discovery of new supplies  Depends on: - rate of use - discovery of new supplies  Resource supply lifetime - oil years - natural gas years - coal years  Resource supply lifetime - oil years - natural gas years - coal years

North American Energy Resources

Oil Resources  Petroleum (crude oil)  Primary recovery - 1/3 recoverable  Secondary recovery - heavy oil (10%)  U.S. is major oil importer - thousands of low-output wells  U.S. is major oil importer - thousands of low-output wells  Saudi Arabia - largest known reserves - supply world for 10 years - Alaskan supply - 6 months  Saudi Arabia - largest known reserves - supply world for 10 years - Alaskan supply - 6 months

OPEC  Organization of Petroleum Exporting Countries  Organization of Petroleum Exporting Countries  Supplies ~30% of U.S. oil imports  #1 Mexico #2 Canada #3 Venezuela (OPEC member)  #1 Mexico #2 Canada #3 Venezuela (OPEC member)

Oil Shale and Tar Sands  Oil shale 3X conventional  Oil shale 3X conventional  Kerogen 25 gallons/ton Energy in=energy out  Kerogen 25 gallons/ton Energy in=energy out  Tar sands  Bitumen 3X return on energy inputs  Bitumen 3X return on energy inputs

Natural Gas  50-90% methane  Propane, butane removed, liquified  Propane, butane removed, liquified  Cleanest burning, lowest costs  Cleanest burning, lowest costs  Problems: leaks, explosions  Problems: leaks, explosions  Unconventional: tight sands X conventional supply, but expensive  Unconventional: tight sands X conventional supply, but expensive

Coal Carbon (energy content) and sulfur

Coal  Bituminous most abundant (52%), but high in sulfur  Bituminous most abundant (52%), but high in sulfur  Anthracite most ideal (high energy, low sulfur), but least abundant (2%)  Anthracite most ideal (high energy, low sulfur), but least abundant (2%)  Subbituminous (38%) moderate energy, moderate pollution potential  Lignite (8%) low energy, low pollution potential  Subbituminous (38%) moderate energy, moderate pollution potential  Lignite (8%) low energy, low pollution potential

Coal  Surface versus subsurface mines

North American Energy Resources

Coal Mining in United States  Western surface mines  Mostly subbituminous, lignite  Used mostly for generating electricity, steel-making industry  Used mostly for generating electricity, steel-making industry  Most used east of Mississippi River  Transportation vs. volume costs, sulfur - slurry pipeline?  Transportation vs. volume costs, sulfur - slurry pipeline?

Burning Coal More Cleanly  Fluidized-Bed Combustion -calcium sulfate used in dry wall

Coal Gasification - methane Raw coal Pulverizer Air or oxygen Steam Pulverized coal Slag removal Recycle unreacted carbon (char) Raw gases Clean methane gas Recover sulfur Methane (natural gas) 2C Coal + O2O2 2CO CO+3H 2 CH 4 +H2OH2O Remove dust, tar, water, sulfur

Coal Liquefaction - liquid fuels  Both gasification and liquefaction lose 30-40% of energy contained in coal  Both gasification and liquefaction lose 30-40% of energy contained in coal

Nuclear Energy  Big question mark in energy industry  Tremendous potential, plagued by safety and cost problems  Tremendous potential, plagued by safety and cost problems  3 ways to produce nuclear power 1) conventional nuclear fission reactor 2) breeder nuclear fission reactor 3) nuclear fusion reactor  3 ways to produce nuclear power 1) conventional nuclear fission reactor 2) breeder nuclear fission reactor 3) nuclear fusion reactor

Nuclear Energy  Use radioactive isotopes  Isotopes - different forms of same element - atoms have differing masses - e.g. U-238, U-235  Isotopes - different forms of same element - atoms have differing masses - e.g. U-238, U-235  Radioactive - unstable atoms emit radiation (rays and particles)  Radioactive - unstable atoms emit radiation (rays and particles)

Nuclear Energy  Conventional fission reactors  Uranium-235 (U-238 common)  Uranium-235 (U-238 common)  Nucleus split by moving neutron - Core, heat exchanger, generator

Reactors in the United States

Nuclear Energy  Breeder fission reactors  Uses plutonium-239 as fuel U neutron = Pu-239  Uses plutonium-239 as fuel U neutron = Pu-239  Pu-239 fissioned, but more produced from U produces more Pu-239 than it uses  Pu-239 fissioned, but more produced from U produces more Pu-239 than it uses

Nuclear Energy  Nuclear fusion reactors  Combine atoms of hydrogen isotopes - deuterium, tritium  Combine atoms of hydrogen isotopes - deuterium, tritium  Requires high temperature million °C - experimental - uncontrolled fusion - hydrogen bomb  Requires high temperature million °C - experimental - uncontrolled fusion - hydrogen bomb

Problems with Nuclear Power  Safety  Disposal of radioactive wastes  Use of fuel for weapons  Reduced growth in demand for electricity  High construction, operating costs  Funding

Safety Concerns  Radiation concerns  Susceptible tissues: reproductive organs, bone marrow, digestive tract, spleen, lymph glands, fetuses  Rem - unit of radiation exposure - 10 rems: low level, few effects rems: sterility, no short-term deaths rems: death in days  Rem - unit of radiation exposure - 10 rems: low level, few effects rems: sterility, no short-term deaths rems: death in days

Annual Radiation Exposure  Average 230 mrem (0.230 rem)  130 mrem from natural sources  100 mrem from human activities mrem from nuclear reactors  130 mrem from natural sources  100 mrem from human activities mrem from nuclear reactors  Lifespan reduced by 1 minute

Big Fears  Core meltdown - Chernobyl ‘86  Core meltdown - Chernobyl ‘86  Containment shell rupture  Both have potential for releasing huge amounts of radiation

Disposal of Radioactive Wastes Nuclear fuel cycle

Disposal of Radioactive Wastes  No long-term storage facility - protected for 10,000 years - radiation declines to low levels  No long-term storage facility - protected for 10,000 years - radiation declines to low levels  Most wastes stored on-site  Site under development - Yucca Mountain in Nevada  Site under development - Yucca Mountain in Nevada

Yucca Mountain

Temporary Storage