Transcript Document
Energy Resources Energy What is Energy ? Many of us would answer…. electricity or or maybe nuclear power gasoline Energy What is Energy ? For many people in LDCs energy is… fuel wood Energy fuel wood • In LDCs used for cooking and heating Energy fuel wood • The “other” energy crisis • A major problem in LDCs fuel wood The “other” energy crisis • As population grows the need for fuel wood energy grows fuel wood trees shrubs & bushes The “other” energy crisis grasses crop residues dried dung The demand for trees fuel wood is shrubs & bushes resulting in soil erosion, grasses soil nutrient crop residues depletion, and land degradation dried dung Energy fuel wood • The “other” energy crisis • A major problem in LDCs Energy In MDCs, abundant energy is vital to society Modern industrial culture is energy intensive Energy & Culture Human cultural evolution has been accompanied by • Increasingly powerful energy sources • Increased per capita energy utilization Energy & Culture Hunter-gatherer society • human muscle power & fire Agricultural society • domesticated draft animals • wind & water power Energy & Culture Early industrial society • coal energy – fossil fuel • steam engines Energy & Culture Modern industrial society • oil & natural gas energy – fossil fuels • internal combustion engines • electrical energy • nuclear energy U.S. Energy Sources Time Period Primary Energy Source Pre - 1850 Fuel Wood From 1850 to 1900 the use of fire wood decreased as the use of coal increased U.S. Energy Sources Time Period Primary Energy Source 1900 - 1950 Coal The use of oil grew during the first half of the 20th century U.S. Energy Sources Time Period Primary Energy Source 1950 - present Oil During the second half of the 20th century, oil use surpassed coal use U.S. Energy Use The United States has about 6% of world population but we use about one-third of the world’s energy U.S. Energy Use High energy use does contribute to a high standard of living but much of our energy is used wastefully The U.S. is an energy GLUTTON U.S. Energy Use We can maintain our standard of living but reduce our energy use through efficiency & conservation Energy efficiency & conservation Doing the same work, but using less energy Our best energy “source” Energy efficiency & conservation Reduces use of fossil fuels Reduces pollution Reduces release of greenhouse gases Energy efficiency & conservation Reduces need for new energy plants Prolongs supplies of fossil fuels Allows more time for development of alternative energies Energy efficiency & conservation Saves money Improves our balance of trade Reduces reliance on imported oil U. S. Reliance On Imported Oil 1973 OPEC Oil Embargo Reduced availability of crude oil Organization of Petroleum Exporting Countries U. S. Reliance On Imported Oil 1973 OPEC Oil Embargo Sharp increase in crude oil prices Prices for gasoline, diesel, and home heating oil sharply increased 1973 OPEC Oil Embargo Rapid increases in costs of consumer products Rapid increase in overall cost of living Period of double-digit inflation 1973 OPEC Oil Embargo Gasoline shortages Long lines at gasoline stations Growing popularity of smaller, fuel-efficient autos 1973 OPEC Oil Embargo National concern for energy conservation and energy independence President Carter called the energy crisis “the moral equivalent of war” 1973 OPEC Oil Embargo The Carter administration increased federal support for alternative energy research and development U. S. Reliance On Imported Oil Unfortunately, federal support for alternative energy research and development declined after the Carter administration The U.S. is now more dependent on imported oil than it was in 1973 Energy Use of Fossil Fuels Coal Natural Gas Petroleum Energy Use of Fossil Fuels Currently, our largest energy source Large-scale use for only about 200 years Energy Use of Fossil Fuels Large-scale use will decline in the future • Decreasing supplies Energy Use of Fossil Fuels Large-scale use will decline in the future • Increasing costs Energy Use of Fossil Fuels Large-scale use will decline in the future • Adverse environmental impacts Use of Fossil Fuels “From the perspective of a 10,000 year time span, human utilization of fossil fuels will seem like a brief, toxic fire aboard a spaceship” Use of Fossil Fuels - 5000 years Present Time + 5000 years Use of Fossil Fuels “From the perspective of a 10,000 year time span, human utilization of fossil fuels will seem like a brief, toxic fire aboard a spaceship” Use of Fossil Fuels Fossil fuels are a nonrenewable resource Nonrenewable – no more of the resource can be obtained within a useful time frame Use of Fossil Fuels Fossil fuels are a nonrenewable resource Geologic formation occurred over millions of years Use of Fossil Fuels Reliance on fossil fuels is non-sustainable Nonrenewable, finite supply Exhaustion of supply will deprive future generations Use of Fossil Fuels Reliance on fossil fuels is non-sustainable Exhaustion of supply will deprive future generations • Energy resource • Synthetic base • Lubricants Use of Fossil Fuels Reliance on fossil fuels is non-sustainable Pollution from use may affect future generations • Global Climate Change • Acid Precipitation • Chemical Pollution Use of Fossil Fuels Reliance on fossil fuels is non-sustainable To work toward a sustainable society, we must make the transition to renewable energy sources Use of Fossil Fuels United States Energy Sources The U.S. is heavily dependent on fossil fuels Approximately 85% of U.S. energy Use of Fossil Fuels United States Energy Sources Petroleum or oil is the largest single source of U.S. energy Approximately 40% of U.S. energy Use of Fossil Fuels United States Energy Sources Natural Gas - Approximately 25% of U.S. energy Coal - Approximately 20% of U.S. energy Use of Fossil Fuels United States Energy Sources Approximately 15% of U.S. energy comes from all other sources • nuclear • wind • hydro • solar • geothermal • other Use of Fossil Fuels United States Energy Sources Oil 40% Coal 20% Natural Gas 25% Non Fossil Fuel 15% Use of Fossil Fuels Total Reserves – the amount left to be recovered Known Reserves – have already been found and quantity estimated Suspected Reserves – thought to exist, but not yet found, quantity uncertain Use of Fossil Fuels Suspected Reserves – thought to exist, but not yet found, quantity uncertain All the “easy” reserves have been found Suspected reserves will be in remote locations and will be difficult and expensive to recover Use of Fossil Fuels How long will fossil fuel reserves last ? Uncertainties in estimates due to • unknown quantities of suspected reserves • will rate of use increase or decrease Use of Fossil Fuels How long will fossil fuel reserves last ? Petroleum – the smallest reserves • at current rate of use, reserves may last 40 – 50 years Use of Fossil Fuels How long will fossil fuel reserves last ? Petroleum – the smallest reserves • yet the one we use the most • most urgent need to find a replacement Use of Fossil Fuels How long will fossil fuel reserves last ? Natural Gas – larger reserves than oil • at current rate of use, reserves may last 60 – 80 years Use of Fossil Fuels How long will fossil fuel reserves last ? Natural Gas – larger reserves than oil • the “cleanest” fossil fuel • likely that rate of use will increase Use of Fossil Fuels How long will fossil fuel reserves last ? Coal – the largest reserves • at current rate of use, reserves may last 200 – 300 years Use of Fossil Fuels How long will fossil fuel reserves last ? Coal – the largest reserves • the “dirtiest” of the fossil fuels • undesirable to burn it all Use of Fossil Fuels Reserves are limited • particularly petroleum Use has adverse effects • on humans • on environment Use of Fossil Fuels What are the “costs” of fossil fuel use ? Costs in a broad sense • includes more than just dollars • includes negative effects on humans and environment Use of Fossil Fuels What are the “costs” of fossil fuel use ? Human costs may include death and illness • difficult to assign a dollar value Use of Fossil Fuels What are the “costs” of fossil fuel use ? Environmental costs may include ecosystem alteration and degradation • difficult to assign a dollar value Use of Fossil Fuels What are the “costs” of fossil fuel use ? Externalization of Costs • someone other than direct producer or direct consumer bears the costs Use of Fossil Fuels What are the “costs” of fossil fuel use ? Externalization of Costs • the “costs” of fossil fuel use are often borne by society as a whole Use of Fossil Fuels Stages of Exploitation • Exploration • Extraction • Processing • Transportation • End Use Costs of Fossil Fuels End Use the most significant human impacts the most significant environmental impacts Costs of Fossil Fuels End Use Global Climate Change • fossil fuel combustion releases CO2 into the atmosphere • atmospheric CO2 traps heat in the atmosphere – global warming Costs of Fossil Fuels End Use Global Climate Change • the most serious and important threat from our reliance on fossil fuels • potential major impacts on life on Earth Costs of Fossil Fuels End Use Global Climate Change • We will consider this important topic in greater detail later in the semester Costs of Fossil Fuels End Use Acid Precipitation • Combustion reactions release nitrogen oxides (NOx) • Combustion of high sulfur fuels releases sulfur oxides (SOx) Costs of Fossil Fuels End Use Acid Precipitation • NOx react with atmospheric H2O to form HNO3 – nitric acid • SOx react with atmospheric H2O to form H2SO4 – sulfuric acid Costs of Fossil Fuels End Use Acid Precipitation • Adverse effects on forests, aquatic ecosystems, structures, human health Costs of Fossil Fuels End Use Acid Precipitation • We will consider this topic in greater detail later in the semester Costs of Fossil Fuels End Use Chemical Pollution • Combustion of fossil fuels results in a variety of chemical pollutants Costs of Fossil Fuels End Use Chemical Pollution • carbon monoxide (CO) • heavy metals • radionuclides Costs of Fossil Fuels End Use Chemical Pollution • hydrocarbons • particulates • ozone Costs of Fossil Fuels End Use Chemical Pollution • polycyclic aromatic hydrocarbons (PAHs) • peroxyacyl nitrates (PANs) Costs of Fossil Fuels End Use Chemical Pollution • pollutant release has adverse effects on human and environmental health Costs of Fossil Fuels End Use Chemical Pollution • We will consider this topic in greater detail later in the semester Costs of Fossil Fuels There are enormous human and environmental “costs” associated with continued use of fossil fuels Energy Alternatives What alternatives are there to the fossil fuels ? • Nuclear Power • Renewable Energies Nuclear Power Nuclear Fission • currently working • energy from chain reaction of a heavy, radioactive element Nuclear Fusion • still experimental • energy from combining light elements to form a heavier element Nuclear Fission Heat is released from the chain reaction of a fissionable radioactive isotope U235 is typical fuel Nuclear Fission Heat produces steam to spin a turbine and generator to produce electricity Nuclear Fission The radioactive fuel is contained in the reactor core Control rods regulate the rate of the chain reaction Nuclear Fission Control rods absorb neutrons to regulate the chain reaction Nuclear Fission Chernobyl – workers improperly withdrew the control rods leading to a run away chain reaction Chernobyl – the run away chain reaction lead to core meltdown and a steam explosion Nuclear Fission U.S. reactors are housed in containment structures Nuclear Fission Chernobyl – the reactor did not have a containment structure Chernobyl – doubtful that a containment structure could have withstood the steam explosion Nuclear Fission What are the pros and cons of nuclear fission ? Nuclear Fission Nuclear power has some advantages over fossil fuels Nuclear Fission PROS relative to fossil fuels • No greenhouse gas emissions • No acid rain emissions • No chemical pollution emissions • No strip mining • No acid mine drainage Nuclear Fission additional PROS • A currently working technology • Very high energy density • Overall good safety record Nuclear Fission What are some of the CONS or negative aspects of nuclear fission ? Nuclear Fission CONS • Risk of accidents -- Chernobyl • Nonrenewable energy source • Limited amount of fissionable isotopes Nuclear Fission Not all radioactive isotopes are fissionable – will undergo chain reaction U238 – the abundant isotope of uranium is not fissionable U235 – is fissionable, but is a relatively rare isotope of uranium Nuclear Fission Breeder Reactors could expand supply of fissionable material Breeder Reactors convert U238 to Pu239 The U.S. closed its experimental breeder reactor at Clinch River, TN Nuclear Fission CONS • Potential proliferation of nuclear weapons • Concern over possible sabotage • Decommissioning old nuclear plants • Disposal of high-level nuclear wastes Nuclear Fission What to do with high-level nuclear wastes ? Some isotopes will remain dangerously radioactive for thousands of years Nuclear Fission The U.S. repository for high-level nuclear wastes is under construction at Yucca Mountain, NV The wastes will be buried deep underground Nuclear Fission The Yucca Mountain project is controversial Until Yucca Mountain is ready, nuclear plants are storing their wastes on site Nuclear Fission CONS Health effects on uranium miners High construction costs and long construction time Lack of private insurance Low public acceptance & support Nuclear Fission Point to Ponder How do you personally feel about nuclear power in the U.S. ? • increase a lot • decrease a little • stay about the same • increase a little • decrease a lot Nuclear Fusion Energy from combining light elements to form a heavier element • Still an experimental technology • Much more energy than nuclear fission • Energy of sun and stars Nuclear Fusion Energy of the solar furnace • The sun can fuse hydrogen atoms together to form iron • Goal of fusion energy on Earth is to fuse hydrogen atoms together to form helium or lithium Nuclear Fusion Nuclear Fusion Challenges to Development • High ignition temperature • Confining the reaction Nuclear Fusion Challenges to Development • High ignition temperature Multiple powerful lasers focused on a single point in space bring frozen deuterium pellet to ignition temperature Nuclear Fusion Challenges to Development • Confining the reaction “magnetic bottle” powerful electromagnets confine reaction in a magnetic field Nuclear Fusion Still an experimental technology Controlled fusion reactions have been achieved However, the “break-even” point has not yet been reached Nuclear Fusion the “break-even” point • Energy output equals energy input • Energy input – ignition and confinement of reaction Nuclear Fusion the “break-even” point Energy output ______________ Energy input = 1.00 Nuclear Fusion Potential Pros • Enormous amounts of energy • Deuterium isotope of hydrogen is abundant in seawater • No radioactive wastes Nuclear Fusion Cons • Not a currently working technology • Timetable for commercial development remains uncertain Renewable Energy Sources Renewable Energy Sources No single renewable energy source will satisfy all energy needs However, combinations of different renewable energies can meet most, if not all, of our energy needs Renewable Energy Sources The exact combination of renewable energies will depend upon geographic location and the energy application Renewable Energy Sources Most renewable energy technologies are sufficiently developed for large scale application TODAY We need to hasten the transition away from fossil fuels and toward renewable energy Renewable Energy Sources Many Pros in common • Renewable – supply will not run out • Low pollution – including CO2 • Prolong supply of fossil fuels • Compatible with a sustainable society Renewable Energy Sources There are many choices available on the renewable energy “menu” There are so many choices available that some less promising technologies will not be widely used for lack of need Renewable Energy Sources Direct Solar Indirect Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis • Wind • Hydropower • Biomass • OTEC Hydrogen Tidal Geothermal Renewable Energy Sources Solar Energy • Primary energy source for essentially all natural ecosystems on earth • Why not the primary energy source for human societies ? Renewable Energy Sources Solar Energy • Direct Solar – directly uses electromagnetic energy of sunlight • Indirect Solar – uses the stored thermal, kinetic, or chemical energy from sunlight Solar Energy Direct Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis Solar Energy Passive solar • Nothing moves – no pumps or working fluid • Relies primarily on architectural design and construction Solar Energy Passive solar • Archeological evidence suggest use in ancient buildings • Primary value is in lighting and space heating and cooling of buildings Solar Energy Passive solar • Tremendous energy expenditures in lighting and space heating and cooling of buildings can be reduced through passive solar designs Passive solar Simple architectural design, such as • placement of windows and • placement of overhangs can reduce energy required for heating and cooling buildings Passive solar winter sun summer sun Passive solar Simple architectural design, such as • Greenhouse or thermal storage by water or masonry Solar Energy Direct Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis Solar Energy Active Solar • A working fluid, usually water, absorbs heat from sunlight and is moved by pumps Solar Energy Active Solar • Multiple Applications Domestic – water and space heating Commercial & Industrial – production of steam and electricity Active Solar Domestic • Water is heated by sunlight in roof top solar collectors Active Solar Domestic • Solar heated water is used in home water heater and can be used for space heating Active Solar Can also be used for production of • Commercial & Industrial – production of steam and electricity Active Solar Solar Energy Direct Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis Solar Energy Photovoltaics • aka – solar cells • originally developed as exotic power source for satellites Photovoltaics Sunlight energy (photons) causes the movement of electrons (current) between layers of silicon to produce directly produce electricity from sulight Photovoltaics • now routine in calculators, outdoor lighting, and other applications • tremendous increase in efficiency • tremendous decrease in cost • exciting developments in design and application Solar Energy Direct Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis Solar Energy Artificial Photosynthesis • An early reaction in natural photosynthesis uses sunlight energy to split water into oxygen and hydrogen Solar Energy Artificial Photosynthesis 2H2O + sunlight 2H2 + O2 • research is in progress to develop an economical way to do this in vitro Solar Energy Artificial Photosynthesis 2H2O + sunlight 2H2 + O2 • this process would produce hydrogen gas Hydrogen Often called “the fuel of the future” Could be a replacement for current transportation fuels Nearly an ideal fuel Hydrogen The primary problem is that there is almost no free hydrogen (H2) on earth The hydrogen is bound in molecules, such as water (H2O) Free hydrogen (H2) must be produced by splitting molecules Hydrogen Production of free hydrogen (H2) by splitting molecules requires a primary energy source Currently H2 is produced by electrolysis of water Electrolysis of water to produce H2 requires substantial electricity Hydrogen Hydrogen energy would be more practical with • direct solar production of H2 • fusion production of electricity • solar production of electricity Hydrogen Hydrogen can be used in combustion engines or in fuel cells In either application, hydrogen fuel produces little-to-no pollution Hydrogen Burning hydrogen fuel in a combustion engine produces water as the end product 2 H2 + O2 2 H2O + heat energy Hydrogen can also be used in fuel cells for production of electricity Water is again the byproduct Hydrogen fuel cells can also run electric motors Renewable Energy Sources Direct Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis Hydrogen Indirect Solar • Wind • Hydropower • Biomass • OTEC Tidal Geothermal Solar Energy Indirect Solar • Wind • Hydropower • Biomass • OTEC Wind Energy How indirect solar ? • Atmospheric movement, wind, is due to differential heating of the atmosphere by the sun Wind Energy Has been used for centuries Currently a well developed technology for production of electricity Wind Energy Most of current U.S. production capacity located in California Large new facilities under construction in Texas Wind Energy Wind turbines are increasing in size and efficiency Wind Energy Many good wind energy sites located across the country Potential for substantial contribution to U.S. energy needs Wind Energy There are some negatives or cons with wind energy The biggest problem is the variable nature of winds • no wind -- no electricity Wind Energy Problem eased by widely geographically located facilities connected to the national power grid • the wind is always blowing somewhere Wind Energy Unfortunately, the rotors of wind turbines can also kill and injure birds • ways to minimize impacts on birds are under study Solar Energy Indirect Solar • Wind • Hydropower • Biomass • OTEC Hydropower How • sunlight indirect solar ? energy evaporates water, lifting it into the atmosphere Hydropower • precipitation from the atmosphere runs downhill by gravity Hydropower • Energy is extracted from the water as it runs downhill Hydropower Has been used for centuries Currently a well developed technology for production of electricity Hydropower In the U.S., most of the good locations for big hydropower dams have been exploited Around the world, many good locations for big hydropower dams have not been exploited Hydropower Small scale hydropower could further contribute to energy needs in rural areas of less developed countries Hydropower Big hydropower dams have multiple pros and cons Dam opponents are calling for removal of some dams Hydropower Big hydropower dams -- pros • electricity generation • water reservoir • flood control • creates recreational area Hydropower Big hydropower dams -- cons • obstacle to fish migration • floods land • disrupts natural water cycle • destroys recreational area Solar Energy Indirect Solar • Wind • Hydropower • Biomass • OTEC Biomass Energy How indirect solar ? • Energy of sunlight used in photosynthesis to form complex organic compounds Biomass Energy Multiple forms • direct combustion • waste to energy • conversion to methane • conversion to alcohol Biomass Energy Biomass Energy A concern common to all forms of biomass energy is the potential for land degradation and soil depletion Solar Energy Indirect Solar • Wind • Hydropower • Biomass • OTEC OTEC What is it ? An acronym for Ocean Thermal Energy Conversion OTEC How indirect solar ? • Utilizes the thermal gradient formed in bodies of water due to warming of surface water by sunlight energy OTEC First proposed more than a century ago Currently an experimental technology OTEC A fluid with a low boiling point is circulated in pipes between warm surface water and cold deep water OTEC The fluid turns to steam at the temperature of surface water and the steam spins a turbo generator to produce electricity OTEC The steam recondenses to fluid as it passes into the cold temperature of deep water The fluid is then pumped back to the surface to repeat the cycle OTEC Has potential to benefit coastal and island areas However, OTEC technology does not seem to be progressing and there is no clear timetable for commercial application Renewable Energy Sources Direct Solar Indirect Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis • Wind • Hydropower • Biomass • OTEC Hydrogen Tidal Geothermal Tidal Power Ocean tides are due to gravitational attraction of the moon – lunar energy Tidal Power Water flowing in or out with the tide spins turbo generators to produce electricity Tidal Power Extremely high tides required Relatively few good sites in the world Tidal Power Required tidal dams disrupt intertidal biological communities Seems destined for failure Renewable Energy Sources Direct Solar Indirect Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis • Wind • Hydropower • Biomass • OTEC Hydrogen Tidal Geothermal Geothermal Energy Not a truly renewable energy source Thought to have a long period of use and often classified with renewable energies Geothermal Energy Heat from the Earth’s interior provides the energy Theoretically available anywhere on Earth – if go deep enough Geothermal Energy Geothermal Energy Good geothermal sites are where “hot rock” is located close to the surface Hot rock heats water to steam to spin a turbo generator to produce electricity Geothermal Energy Geothermal Energy Currently a well developed technology for production of electricity Many good geothermal sites located across the country Geothermal Energy Renewable Energy Sources Direct Solar Indirect Solar • Passive solar • Active solar • Photovoltaics • Artificial Photosynthesis • Wind • Hydropower • Biomass • OTEC Hydrogen Tidal Geothermal There are enormous human and environmental “costs” associated with continued use of fossil fuels Renewable energies are available today !