11 Nonrenewable Energy and Electricity Chapter 16

22 ENERGY SOURCES AND USES Work - Application of force through a distance. Energy - The capacity to do work. Power - Rate at which work is done.  Calorie - Amount of energy necessary to heat 1 gram of water 1 o C.  Joule - Amount of work done when a force of 1 Newton is exerted over 1 meter.

© 2013 Pearson Education, Inc Energy Production and Consumption Energy sources –Primary energy Energy contained in natural resources –Coal, oil, sunlight, wind, uranium –Secondary energy When primary energy is converted into another form –electricity

© 2013 Pearson Education, Inc Energy Production and Consumption End use –Final application of energy –Running a car or computer Second law of thermodynamics –Energy lost in each conversion Energy conversion efficiency –Percentage of primary source energy that is captured in secondary form Energy end-use efficiency –Product of all of the energy conversions and end use –100 units of coal powers a light bulb that produces 1.2 units of light energy, 1.3% efficiency

© 2013 Pearson Education, Inc Energy Production and Consumption Forms of primary energy –Nonrenewable Derived from sources that exist in limited quantities –Fossil fuels –Nuclear –Renewable Sources that are not depleted when used or can be replenished quickly –Solar –Wind –Wood

© 2013 Pearson Education, Inc. Primary Energy Source Chemical energy 100 units 70 units lost as heat as the chemical energy in coal is transformed to electrical current 6 units lost as heat due to resistance in transmission lines 22.8 units lost as heat as electrical current is converted to visible light Electric current 30 units Electric current 24 units Visible light 1.2 units Generation Transmission End use

How We Use Energy What are the commercial uses of energy? –Industry uses 38%; –Residential and commercial buildings use 36%; and, –Transportation uses 26%. Half of all energy in primary fuels is lost during conversion to more useful forms while being shipped or during use. –Nearly two-thirds of energy in coal being burned to generate electricity is lost during thermal conversion in the power plant. Another 10% is lost during transmission and stepping down to household voltages. Natural gas is the most efficient fuel. –Only 10% of its energy content is lost during shipping and processing. Ordinary gas-burning furnaces are about 75% efficient. High-economy furnaces can be 95% efficient.

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Energy Use Trends A general trend is for higher energy use to correlate with a higher standard of living In an average year, each person in the U.S. and Canada consumes more than 300 times the amount of energy consumed by a person in one of the poorest countries of the world; however, Several European countries have higher living standards than the U.S., yet they use about half as much energy. Per Capita Energy Use & GDP

 10 Current Energy Sources Fossil Fuels currently provide about 86% of all commercial energy in the world.  Other renewable sources make up 9.5% of commercial power.  Nuclear power makes up 6.5% of commercial power.

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15.1 Energy Production and Consumption End use –Rates of primary energy consumption vary by country –Consumption broken into four sectors Transportation Industry Residential/ commercial Electricity

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 14 How Energy is Used Largest share of energy used in the U.S. is consumed by industry (32.6%). Residential and Commercial buildings use 37.6% of primary energy consumed in U.S. Transportation consumes about 26% of all energy used in the U.S.  Three trillion passenger miles and 600 billion ton miles of freight carried annually by motor vehicles in the U.S.

 15 How Energy Is Used Cont’d About half of all energy in primary fuels is lost during conversion to more useful forms while being shipped, or during use.  Nearly two-thirds of energy in coal being burned to generate electricity is lost during thermal conversion in the power plant. - Another 10% is lost during transmission and stepping down to household voltages.

 16 How Energy Is Used Cont’d Natural gas is most efficient fuel.  Only 10% of its energy content is lost during shipping and processing. - Ordinary gas-burning furnaces are about 75% efficient. - High-economy furnaces can be upwards of 95% efficient.

© 2013 Pearson Education, Inc Energy Production and Consumption Future energy portfolios Future patterns depend on four factors –Size of reserves Proven reserves –Extraction rates Reserves-to-production ratio –Market price –Energy return on investment –Environmental impacts

 18 Natural Resource Categories

© 2013 Pearson Education, Inc Electric Power—Generation, Distribution, and Use Generating electricity –Electric current flow of electrons through a wire Measured in amperes Electric potential measured in volts –Electric power measured in kilowatt hours (kWh) –Electricity generated in power plants using turbines to drive electric generators

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15.2 Electric Power—Generation, Distribution, and Use Transformers –Reduce amperage and increase voltage to facilitate transmission Multiple power plants feed the power grid –Electric power grid Network of transmission lines and transformers –Base load Minimum amount of electricity for consumer needs Peak load Maximum amount of electricity consumers demand

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15.2 Electric Power—Generation, Distribution, and Use Environmental impacts Electromagnetic field produced by transmission lines Polychlorinated biphenyls (PCBs) in transformers Chemicals from batteries –Lead –Heavy metals

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FOSSIL FUELS Fossil fuels are organic chemicals created by living organisms that were buried in sediments millions of years ago and transformed to energy-rich compounds. Because fossil fuels take so long to form, they are essentially nonrenewable resources.  Coal  Oil  Natural Gas

Oil Coal Natural Gas

© 2013 Pearson Education, Inc Coal Coal formed from plants hundreds of millions of years ago Deposited in layers of sediment called coal seams Types of coal –Lignite –Sub-bituminous –Bituminous –Anthracite

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15.3 Coal Extraction and processing –Removed from sediments by underground and surfacing mining Cleaned to remove dirt and other impurities –Globally, 67% used for electricity generation (90% in United States) Transformed into electricity at coal-fired power plants –Burned to create steam for steam turbines

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15.3 Coal Environmental impacts –Mining destroys habitats Mountaintop removal –Mine tailings are acidic –Exhaust from coal fires Numerous toxins Mercury CO 2

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Coal Extraction and Use Mining is dangerous to humans and the environment Coal burning releases large amounts of air pollution, and is the largest single source of acid rain in many areas. Economic damages are billions of dollars 900 million tons of coal are burned in the U.S. for electric power generation. As a result, multiple pollutants are released such as: –Sodium Dioxide (18 million metric tons) –Nitrogen Oxides ( 5 million metric tons) –Particulates (4 million metric tons) –Hydrocarbons (600,000 metric tons) –Carbon Dioxide (1 trillion metric tons)

© 2013 Pearson Education, Inc Oil Sources and amounts –Oils formed under specific geological conditions Found only in a few places –Formed from remains of microorganisms millions of years ago –Became trapped beneath impermeable rock Oil reservoirs

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15.4 Oil Oil extraction and processing –Crude oil is pumped from reservoirs and sent to refineries Primary oil recovery –Original flow (first 20%) Secondary oil recovery –Additional methods, injecting water Tertiary oil recovery –Injection of CO 2 steam –Fracking

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15.4 Oil Environmental impacts Drilling and transportation of oil –Spills Combustion products –Carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxides –Greenhouse gas emissions

Oil Extraction and Use The countries of the Middle East control two-thirds of all proven-in-place oil reserves. Saudi Arabia has the most. The U.S. has already used up about 40% of its original recoverable petroleum resource. Oil combustion creates substantial air pollution. Drilling causes soil and water pollution. Often oil contains a high sulfur level. Sulfur is corrosive, thus the sulfur is stripped out before oil is shipped to market. Oil is primarily used for transportation providing > 90% of transportation energy. Resources and proven reserves for the year 2000 are 650 billion barrels (bbl). 800 bbl remain to be discovered or are currently not recoverable.

© 2013 Pearson Education, Inc Natural Gas Sources and amounts Formed in the same way as oil Usually found in association with crude oil deposits Also found with coal seams 65-year supply exists at current consumption rates

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15.5 Natural Gas Extraction and processing –Sent by pipeline to refinery –Converted to liquefied natural gas (LNG) –Largest use industrial and power generation –Some used for production of plastics, fertilizers, and synthetic fibers –31% used to generate electricity

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15.5 Natural Gas Environmental impacts Has fewer effects than coal or oil Fracking for natural gas may contaminate aquifers Burning releases CO 2 –Half as much as coal

Natural Gas Consumption Proven world reserves and resources of natural gas equal 3,200 trillion cubic feet. This equals a 60 year supply at present usage rates. Natural gas produces only half as much CO 2 as an equivalent amount of coal. Problems: difficult to ship across oceans, to store in large quantities, and much waste from flaring off. World’s third largest commercial fuel (23% of global energy used). Produces half as much CO 2 as equivalent amount of coal. Most rapidly growing used energy source.

 56 NUCLEAR POWER President Dwight Eisenhower, 1953, “Atoms for Peace" speech.  Nuclear-powered electrical generators would provide power “too cheap to meter.” - Between , American utilities ordered 140 new reactors.  100 subsequently canceled.  Electricity from nuclear power plants was about half the price of coal in 1970, but twice as much in 1990.

© 2013 Pearson Education, Inc Nuclear Power Sources and amounts –Uses heat generated by fission of atoms –Uses decay of uranium Uranium found in many locations –Reserves for 120 years –Produces 16% global electricity

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15.6 Nuclear Power Uranium extraction and processing –Uranium extracted by open pit mines –Uranium ore crushed into fine powder and processed into yellowcake –Yellowcake converted to gas and centrifuged to produce uranium fuel pellets –Fuel pellets packed into rods –100–300 fuel rods packed into assemblies –3,000 assemblies make a reactor core

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 62 How Do Nuclear Reactors Work Cont’d When struck by neutrons, radioactive uranium atoms undergo nuclear fission, releasing energy and more neutrons.  Triggers nuclear chain reaction.

 63 Nuclear Fission

 64 How Do Nuclear Reactors Work Cont’d Reaction is moderated in a power plant by neutron-absorbing solution (Moderator).  In addition, Control Rods composed of neutron-absorbing material are inserted into spaces between fuel assemblies to control reaction rate. - Water or other coolant is circulated between the fuel rods to remove excess heat.

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 66 Kinds of Reactors 70% of nuclear power plants are pressurized water reactors.  Water circulated through core to absorb heat from fuel rods. - Pumped to steam generator where it heats a secondary loop.  Steam from secondary loop drives high-speed turbine producing electricity.

 67 Kinds of Reactors Cont’d Both reactor vessel and steam generator are housed in a special containment building preventing radiation from escaping, and providing extra security in case of accidents.  Under normal operating conditions, a PWR releases very little radioactivity.

 68 PWR

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15.6 Nuclear Power Environmental impacts Benefits and costs are hotly disputed –Large open pit mines –Thermal discharge –Meltdown –Radiation leak –Nuclear waste –Does not release greenhouse gases

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 72 Nuclear Wastes Production of 1,000 tons of uranium fuel typically generates 100,000 tons of tailings and 3.5 million liters of liquid waste.  Now approximately 200 million tons of radioactive waste in piles around mines and processing plants in the U.S.

 73 Radioactive Waste Management About 100,000 tons of low-level waste (clothing) and about 15,000 tons of high-level (spent-fuel) waste in the U.S.  For past 20 years, spent fuel assemblies have been stored in deep water-filled pools at the power plants. (Designed to be temporary) - Many internal pools are now filled and a number plants are storing nuclear waste in metal dry casks outside.

 74 Radioactive Waste Management Cont’d U.S. Department of Energy announced plans to build a high-level waste repository near Yucca Mountain, Nevada in  Facility may cost between $10 and 35 billion, and will not open until at least 2010.

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