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Lecture Presentation Chapter 17 Capturing Energy Bradley Sieve Northern Kentucky University Highland Heights, KY © 2014 Pearson Education, Inc. 17.1 Electricity Is a Convenient Form of Energy • Electricity can easily be transported to many sites – The energy originates in other forms of energy – Losses are associated with the transfer of types © 2014 Pearson Education, Inc. 17.1 Electricity Is a Convenient Form of Energy • Electricity – Flow of electric charge – Generated when a metal wire is moved through an electric field • Electric Generator – Armature—loops of wire wrapped around an iron core – Turbine—paddle wheel that turns the armature © 2014 Pearson Education, Inc. 17.1 Electricity Is a Convenient Form of Energy © 2014 Pearson Education, Inc. 17.1 Electricity Is a Convenient Form of Energy • Steam Turbines – Use steam to turn the turbine and produce the electricity – Boiling the water requires an energy source • Gas Turbines – Driven by combustion products – Require energy for the combustion reaction © 2014 Pearson Education, Inc. Concept Check Is electricity more accurately thought of as a source of energy or as a carrier of energy? © 2014 Pearson Education, Inc. Concept Check Electricity is energy that is readily transported through wires. In this sense, it is best thought of as a carrier of energy. The energy of electricity is used to run a lightbulb, true, but the source of this energy is not the electricity. Rather, the electricity is merely delivering the energy that was generated by some electric generator, which received energy from some nonelectric source, such as a fossil fuel or a waterfall. © 2014 Pearson Education, Inc. 17.1 Electricity Is a Convenient Form of Energy • Power – The rate electrical energy is expended – Measured in watt, 1 watt = 1 joule/second – Average house uses 800 watts – Peak usage is much higher © 2014 Pearson Education, Inc. 17.1 Electricity Is a Convenient Form of Energy Sources of Power in the United States © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Fossil Fuels – Are a nonrenewable energy source • Some types may be depleted in 100 years – Are available in many regions of the world – Gram for gram store more chemical energy than other sources – Are portable and make excellent fuels © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Gases from fossil fuels have negative environmental effects and are – Acid rain sources – Components of smog – Causes of global warming © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Fossil fuels exhibit many physical phases – Coal is a solid – Petroleum (crude oil) is a liquid – Natural gas is a gas • The different phases allow for a wide variety of uses and transport methods © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Methane Hydrate – Methane gas captured in frozen water – Found in the ocean floor – No shortage of this material but difficult to extract © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Coal – Energy available is estimated 10 times larger than petroleum and natural gas – Filthiest fossil fuel due to materials contained within the solid – Burning of coal releases sulfur dioxide, nitrogen oxides, and carbon dioxide – Provides 45% of electric power in the United States © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Extracting coal is harmful to humans and the environment – Underground mines are dangerous to miners – Strip mining destroys the entire ecosystem in the area © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Minimizing Environmental Impact – Flotation—separating impurities from coal by using density differences – Scrubber—capturing the by-products of combustion as they are released © 2014 Pearson Education, Inc. Concept Check What is the major advantage of using coal as an energy source? © 2014 Pearson Education, Inc. Concept Check Coal is relatively abundant, which means it can be used as an energy source for many years to come. © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Petroleum – Liquid form of fossil fuels allowing for easy transport and storage – Contains all of the commercially important hydrocarbons for many different fuels – Contains fewer impurities than coal – Used to produce organic chemicals and polymers © 2014 Pearson Education, Inc. 17.2 Fossil Fuels Are Widely Used but Limited Fuel Source • Natural Gas – Burns cleaner than petroleum and coal – Must be stored in storage tanks – Difficult to transport and isolate – Produces less carbon dioxide than other forms of fossil fuels © 2014 Pearson Education, Inc. Concept Check Of the three forms of fossil fuels, which is most abundant worldwide? Which burns most cleanly? Which is easiest to transport? © 2014 Pearson Education, Inc. Concept Check Coal is the most abundant. Because it contains few impurities, natural gas burns most cleanly. Because it is a liquid, petroleum is easiest to transport. © 2014 Pearson Education, Inc. 17.3 Issues of the Nuclear Industry • Two Forms of Nuclear Energy – Fission is the splitting apart of large nuclei – Fusion is the combining of two small nuclei © 2014 Pearson Education, Inc. 17.3 Issues of the Nuclear Industry • Nuclear Fission – Used in commercial energy production since the 1950s – Produces roughly 20% of electrical energy – Worldwide about 436 fission reactions are used © 2014 Pearson Education, Inc. 17.3 Issues of the Nuclear Industry • Expanded use of nuclear energy can reduce dependence on fossil fuels • Nuclear energy plants do not release atmospheric waste but do produce nuclear wastes • This nuclear waste must be stored in a safe location © 2014 Pearson Education, Inc. 17.3 Issues of the Nuclear Industry • Nuclear energy plants also pose the risk of releasing nuclear waste into the environment – Three Mile Island in 1979 – Chernobyl meltdown in 1986 – Fukushima reactors in 2011 • Design of the facility has a large effect on the overall damage to the environment © 2014 Pearson Education, Inc. Concept Check What is the major disadvantage of nuclear fission as an energy source? © 2014 Pearson Education, Inc. Concept Check Nuclear fission reactors generate large amounts of radioactive wastes that require permanent large-scale storage facilities. © 2014 Pearson Education, Inc. 17.4 What Are Sustainable Energy Sources • Sustainable Energy Source – Ideally is an inexhaustible source along with being environmentally benign – Ultimate sustainable source is the Sun – Other astronomical sources include • Warm interior of Earth • Tidal forces © 2014 Pearson Education, Inc. Concept Check What is a sustainable energy source? © 2014 Pearson Education, Inc. Concept Check A sustainable energy source has the potential to be available indefinitely. The technologies that take advantage of these sources should be environmentally benign. © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity • Hydroelectric Power – Power from the kinetic energy of flowing water – One example is a hydroelectric dam • Supplies 10% of energy in the United States • 2400 dams of the roughly 80,000 dams are outfitted to produce electricity • Many are built with inefficient technology by today’s standards © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity • Drawbacks to Hydroelectric Dams – No pollutants released, but local environments are affected – Flow of traffic blocked in the waterway – Buildup of silt behind the dam – Downstream cropland can be lost – Upstream flooding occurs © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity • Ocean Thermal Energy Conversion (OTEC) – Uses differences in water temperature to create electricity – Low-boiling liquid is vaporized and pushes a turbine – Condenses when exposed to cooler water – Limited to regions where large differences in water temperature occur © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity • Geothermal Energy – Energy from the Earth’s interior – Hydrothermal energy uses this energy to pump hot water or steam from the ground – Energy costs are competitive to fossil fuels – Disadvantages include emission of pollutants, disposal of extracted waters, and geological effects of withdrawing water in unstable regions © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity © 2014 Pearson Education, Inc. 17.5 Water Can Be Used to Generate Electricity • Tidal Power – Use of ocean tides to create power – Tidal waters move through a dam, creating power – Large-scale prospects are not good due to limited locations and destruction of the sites © 2014 Pearson Education, Inc. Concept Check Of the forms of water power discussed in this section, which are solar in origin? Which is lunar? Which is derived from the Earth’s hot interior? © 2014 Pearson Education, Inc. Concept Check The energy obtained from dams, from ocean thermal energy conversion, and from a geothermal heat exchanger is solar because they all involve water’s being warmed by the Sun. Tidal energy is lunar, and other forms of geothermal energy are derived from the Earth’s hot interior. © 2014 Pearson Education, Inc. 17.6 Biomass Is Chemical Energy • Biomass – The energy contained within plant material – Methods to use the energy • Produce transportable fuels from the material • Burn it at a power plant – Biomass power generation if carbon-neutral • Amount of carbon dioxide is equal growing and burning it © 2014 Pearson Education, Inc. 17.6 Biomass Is Chemical Energy • Fuels from Biomass – Ethanol has a higher octane rating than gasoline and was once the preferred fuel for cars – Cars running on pure ethanol (E100) do not add extra carbon dioxide than is used in growing the biomass – Ethanol is relatively expensive due to gasoline price being held artificially low © 2014 Pearson Education, Inc. 17.6 Biomass Is Chemical Energy • Ethanol Sources – Corn • Primarily in the United States • 49 billion liters produced in 2010 – Sugar cane • Primarily in Brazil • 28 billion liters produced in 2010 – Ideal material is cellulose found in all plants © 2014 Pearson Education, Inc. 17.6 Biomass Is Chemical Energy • Biomass can be burned – Higher efficiency than when changing into a fuel – Most sources are wood and wood waste – Cities experimenting with burning solid waste – Energy is used to produce steam and turn a traditional turbine © 2014 Pearson Education, Inc. Concept Check What do biomass and fossil fuels have in common? © 2014 Pearson Education, Inc. Concept Check They both originate from solar energy. © 2014 Pearson Education, Inc. 17.7 Energy Can Be Harnessed from Sunlight • Solar Heat – Easily collected to heat water – 15% of energy use is for heating water – Water can then be used for washing © 2014 Pearson Education, Inc. 17.7 Energy Can Be Harnessed from Sunlight • Solar Thermal Electric Generation – Producing electricity from sunlight – Heats a material that is then used to create steam when needed © 2014 Pearson Education, Inc. 17.7 Energy Can Be Harnessed from Sunlight • Wind Power – Widely available and cheap – Wind turbine turns in the wind to create electricity – Costs have been lowering over the years – 239 gigawatts of capacity worldwide © 2014 Pearson Education, Inc. 17.7 Energy Can Be Harnessed from Sunlight • Drawbacks to Wind Power – Power generation is located far from largest power needs – Aesthetic issues for some people – Hazards for wildlife, especially birds © 2014 Pearson Education, Inc. Concept Check What do fossil fuels have in common with the various forms of direct solar energy just discussed? © 2014 Pearson Education, Inc. Concept Check They all originate with the Sun. © 2014 Pearson Education, Inc. 17.7 Energy Can Be Harnessed from Sunlight • Photovoltaics – Convert sunlight directly to electricity – Most direct manner to convert sunlight to electrical energy – Cost of electricity is tied to equipment cost – Minimal maintenance and no water needed © 2014 Pearson Education, Inc. 17.8 Solar Energy Can Be Stored as Hydrogen • Hydrogen is an ideal fuel – Most energy per weight of all fuels – Readily produced from water, which can be run off solar power – Burns cleanly, emitting only water vapor – Easily transported through pipelines – Can be used to power automobiles © 2014 Pearson Education, Inc. Concept Check Why does the combustion of hydrogen produce no carbon dioxide? © 2014 Pearson Education, Inc. Concept Check There is no carbon with which to form carbon dioxide. Hydrogen is an ideal fuel that, when burned, produces almost nothing but water vapor—no carbon dioxide, no carbon monoxide, and no particulate matter. © 2014 Pearson Education, Inc. 17.8 Solar Energy Can Be Stored as Hydrogen • Fuel Cells – An efficient means to produce electricity – Roughly 60% efficiency compared with 34% in coal-fired power plants – One potential H source is treatment of coal – Coal not burned directly creates fewer pollutants © 2014 Pearson Education, Inc. 17.8 Solar Energy Can Be Stored as Hydrogen • Photovoltaic Cells – Can produce hydrogen directly from water using sunlight – 60% efficiencies are expected from research – Materials are still being optimized for the process © 2014 Pearson Education, Inc. 17.8 Solar Energy Can Be Stored as Hydrogen • Distributed versus current centralized energy sources – Photovoltaic and wind turbines can be distributed to points of use – Avoids losses due to transport of the fuel – Supplement current utilities to meet the everincreasing demand © 2014 Pearson Education, Inc. 17.8 Solar Energy Can Be Stored as Hydrogen • Drawbacks to Hydrogen – Fossil fuels will likely be the primary source of hydrogen – Major breakthroughs are need to make the process cost effective – Concentrating on hydrogen technologies may leave other alternatives underfunded © 2014 Pearson Education, Inc. 17.8 Solar Energy Can Be Stored as Hydrogen • Putting Things in Perspective – Nearly 25% of all power plants will need major renovations within the next few years – Population growth and emerging nations are demanding more and more energy – Energy conservation and improved technologies are helping – Controlling population growth is likely easier than providing electricity and basic needs for everyone © 2014 Pearson Education, Inc. 17.8 Solar Energy Can Be Stored as Hydrogen © 2014 Pearson Education, Inc.