BIOL 4140

Contemporary Problems in Environmental Science

Phil Ganter

302 Harned Hall

963-5782

A limpet and acorn barnacles

Energy I: Energy Basics and Non-Renewable Energy Sources

Chapter 7

Email me

Back To:
TSU Home Page
Ganter Home Page

Unit Organization:

Reading:

Textbook: Chapters 7 and 8

Ancillary Reading:

  • 5.38,

Energy and Its Measurement

Energy and Measuring Energy

Energy has the worst definition of any "thing" I know of.  No one I know seriously denies it's existence but no one has ever been able to tell me what it is.  So, you won't be getting a better definition from me unless I am struck by a thunderbolt (electromagnetic energy, I believe).

  • "the ability to do work"
  • What is work? 
    • Work is done when you force something to move some distance, like driving your car down the block (the engine does the work, you just add to its work) or forcing ions across the cell membrane of a neuron (which is why thinking is work, real work)
      • We won't go into a definition of distance here but a definition of force will be needed if we are to understand work
        • Force depends on the mass of the object being moved and the acceleration to which it is exposed. 
        • We measure mass in grams (or a multiple) and acceleration in meters per second per second. 
        • If we accelerate 1 kilogram of mass 1 meter per second per second, we are applying 1 newton of force.  Back to work:

W = Fd, or work = force times distance

    • So, if we apply 1 newton of force and move something a meter, we have done 1 joule of work
  • Energy is measured in the same units as work, so one joule of energy expended to do the work described above but energy is not the same as work
    • Energy, not work, can be stored as potential energy
    • Energy is found in many useful forms: photons, kinetic energy, and various kinds of potential energy (a chemical bond, an electrochemical gradient)
  • Energy efficiency is simply the proportion of work done divided by the energy expended (or by the energy put into the system)
  • Power is related to energy.  Power is work per unit time and is measured in watts (1 W = 1 J per second), so every kilowatt (kW, 1000 watts) uses up

There are several systems to measure energy and you might see any of them used.  In addition, you should get some feel for the units used for large-scale descriptions like US or global energy consumption.

  • Joule (J) or erg (for global purposes, the petajoule (PJ) = 1015 J) - these are in the metric system
  • Calorie (cal, = 4.184 joules) or kilocalorie (kcal) - the calorie listed on food packages is actually a kilocalorie
  • British Thermal Unit (BTU = 1055 joules or 3.968 kcal) or Quad (quadrillion BTUs, 1015 BTUs - could also be called a petaBTU but that would be mixing metric prefixes with non-metric measurements)
    • When reading graphs or tables about worldwide energy consumption, PJs or Quads are used (1 Quad is about 1000 PJs)
  • Metric Tons of Oil Equivalent (toe) - a metric ton is 1000 kilograms (about 2,200 lbs) and the energy in one metric ton of oil is about 41.9 x 109 joules and a million toes (Mtoe) is about 41.9 PJ or 0.04 Quad
    • more on oil - a barrel (bbl) of oil is 42 gallons or 159 liters and a liter is about a kilogram [a bit less, as oil is not as dense as water], so one metric ton of oil is about 6.3 barrels of oil
  • US consumption of energy in 2010 was about 98 quads, which translates into 24.5 billion barrels of oil
    • However, only about 26 of the 98 quads came from oil, so actual oil consumption was about 6.4 billion barrels, or about 19 billion barrels per day (remember, this is just in the US), most of which goes into transportation)

Global Energy Consumption

  • Total energy consumption is subject to the general rule for global impact:

impact is equal to consumption times population:

I = C x P

  • So increases in consumption can be due to both increasing population (we know this is still occurring) or to increases in per capita consumption of energy
    • As the economies of Brazil, Indonesia, India and China grow, the per capita energy consumption of their citizens grows, and this fuels global per capita growth
Update of the Book - the global recession caused a reversal of the usual increase in energy consumption, but the recovery as restored the historical trend of ever-increasing energy consumption
  • Worldwide energy consumption has increased dramatically since 1970.
    • 12,002 Mtoe in 2010 - This is a 7.5% increase over 2009 consumption and 12% over 2003
    • Economic slowdown in 2008/9 caused a reduction worldwide but that was only a temporary trend that reversed to the long-term pattern of yearly increase in 2009/10
  • Energy Consumption Patterns
    • Most of the industrialized world relies on fossil fuels.
      • Order of importance is Oil then Coal then Natural Gas then Renewable Energy (mostly hydroelectricity) then Nuclear
    • How people consume energy is tied to their per capita incomes
      • Those with low incomes rely on biomass or traditional fuels for energy consumption, especially for cooking (fuel wood, charcoal, and animal and plant wastes).
      • Middle income brings energy usage for refrigeration and transport
      • High income users add air conditioning, communications technology, and household appliances
      • Update to the book:  IEA figures show that in 2009, 1.3 billion people had no access to electricity (19% of world population) and 2.7 billion (39%) used biomass for cooking, their primary direct energy-consuming activity
    • There are regional patterns to energy consumption
      • Asia has become the biggest producer and consumer of energy and has accounted for much of the recent growth in energy consumption
      • As countries develop, they consume more energy per capita but the relationship is not a straight line
      • Once development is complete, energy consumption continues to grow

    FOOTPRINTS

  • There is a large disparity in per capita consumption among countries
    • As economic and industrial development occurs, one must ask about how that development might affect energy consumption
    • The current per capita energy consumption of the US is 6.9 toe
      • total consumption is 2160 Mtoe
    • India, China, Brazil, Indonesia, and Russia have all shown significant economic growth in the past decade
      • total consumption of all 5 countries is 3,678 Mtoe
    • World consumption is 11,164 Mtoe
      • If just India, China, Brazil, Indonesia, and Russia expended energy like the US, world consumption would go up 194 %
    • Ultimate goal of development would include large jumps in consumption in many more countries
      • Lets add Africa first, which in 2011 has 1.02 billion people who consume 360 Mtoe of energy
      • At the US per capita rate, Africans would consume 7,052 Mtoe
      • World consumption goes up 257 %

    US Pattern of Energy Consumption

  • How much of the energy you use is used to cook your food?  More or less than your car?  Your heating?
    • The U.S. is the leading consumer and producer of primary energy in the world.
    • The U.S. consumes about 25% more energy than it produces.
    • Much of U.S. energy comes from fossil fuels
    • Consumption dropped during the recent recession, but has regained its steady growth in the last three years
  • 98 Quads - Total Energy Use by the US
    • Sources:
      • 00.1 Quad - Solar
      • 08.4 Quad - Nuclear
      • 02.5 Quad - Hydroelectricity
      • 00.9 Quad - Wind
      • 00.2 Quad - Geothermal
      • 24.7 Quad - Natural Gas
      • 20.8 Quad - Coal
      • 04.3 Quad - Biomass
      • 40.0 Quad - Petroleum
    • 39.5 Quads of the supply goes into electricity generation
      • all nuclear, hydro, solar, wind, almost all coal, most of geothermal, and about 1/3 of Natural gas
      • 26.78 of the energy is lost (does not generate electricity (almost 68%)
    • Consumption:
      • 00.1 Quad - Residential
      • 00.1 Quad - Commercial
      • 00.1 Quad - Industrial
      • 00.1 Quad - Transportation
    • Of the 98 quads, 56.1 Quads are lost  to inefficiency and the third law (this includes that lost in electricity generation)
      • Transportation is the least efficient, where 20.3 Quads out of 27.6 are lost (75%)
      • Residential use is the most efficient, where 2.2 out of 11.8 Quads are lost (18%)
  • Consumption varies geographically in the US
    • Large states (in both land and population) use the most
    • Per capita usage is high in cold states and lowest in the Northeast
    • Louisiana has unusually high per capita rate
  • Fossil fuel consumption is affected by price
    • As the relative price of coal, natural gas, and oil varies, so does the pattern of consumption, with cheap fuel use increasing and expensive fuel use decreasing

Electricity

Generated by many energy sources, it is the real energy “currency” and, if electric vehicles become the norm, its status will be further enhanced

  • Fossil fuels (coal, petroleum, gas)
  • Nuclear fuel
  • Waste
  • Renewable Fuels (Geothermal, wind, solar, Hydropower)

A large portion of the energy sector is devoted to supplying consumers with electricity to run electrical appliances, lighting, heating, and so forth

  • Most commercial power plants are described by the type of primary energy used to operate the turbine-driven generators.

Industry is taking a bigger bite of the global total

  • Now 24%, up from 20% in 2008
  • Industry is becoming more efficient globally as technology goes global
    • The energy needed to produce 1 unit of “added value” by industry is dropping worldwide
    • 1. Industrial energy consumption is getting more efficient worldwide
    • 2. Efficiencies are becoming more uniform as modern methods spread

Electricity Generation

Michael Faraday is credited with discovering that a charged particle will be pushed along by a moving
magnetic field (and vice versa)

  • This principle of electromagnetic induction is the basis for both electric generators and motors
  • The generator in your car is a small version of the generators in power plants

Magnetism

  • A magnetic field is generated by the motion of a particle with an electric charge (for instance, an electron)
    • No motion, no field but electrons are always in motion
  • Some atoms have electron arrangements that give the overall atom a strong magnetic field
    • Fe, Co, and Ni are the common ones at room temperature
  • Only unpaired electrons contribute to the atom's magnetism
    • pairs are always moving in opposing directions, thus canceling each other out
  • Magnetism (a coherent magnetic field around an object) can be induced in some materials with moderately magnetic atoms by applying a current so that the magnetic moments of the component atoms align
  • The effect of the individual atomic “magnets” adds up
  • Some atoms have electron configurations that give the overall atom a magnetic field and a crystal structure that encourages them to form magnetic “domains” – clusters of aligned atoms (very small but with about a quad of atoms in each domain)
    • If the domains in a bar of iron are in alignment, then the entire bar has a coherent magnetic field
    • One way to get them to align is to put them into the field of a pre-existing magnet!

Electromagnetic induction

  • caused by moving a magnetic field past a copper wire (or some other conducting material)
    • A lot of electrons moving in the same direction down a wire is a current
    • the energy in this movement can be used to do lots of different kinds of work: heating, computing, etc.
    • The magnetic field will cause the “free” electrons in the conductor to move according to the “right hand rule”.
  • So, how do we get the magnet to move?
    • just spinning it is movement enough
    • We need to turn a shaft fixed to the magnet
    • This turning is accomplished by a turbine
      • A turbine is a mechanism composed of blades attached to a shaft that, when fluid (steam, often) flows by them, are pushed so that they turn the shaft.
      • If you run this in reverse, you have a compressor or a pump!
      • A windmill is a kind of turbine

Electrification

Two sources:

  • Grid Electricity - electricity generated from a central power plant and distributed to many users through wires
    • The wires form a grid that interconnects power plants
    • The Grid
      • Grew as local power companies extended their serivce areas and began to interconnect power lines for improved stability
      • Is managed by agencies (called "Balancing Authorities") set up by groups of power companies
      • Balancing Authorities constantly monitor demand locally and call up local and distant generation plants to satisfy local demand
        • The normal priority is price-based (cheapest used first) but during peaks, other criteria are used (all suppliers get paid at the rate that the most expensive supplier receives)
        • In the future, environmental costs may become part of the prioritization criteria (call up polluters last)
    • The Grid may be the most complex machine on Earth
  • Individual generators or solar cells that supply electricity directly to a single user.

Supplying the People with Electricity

  • Electrification of the US
    • By the 1870's, electrical generators were for sale in Europe and the US
    • In 1879 in the US (Edison) and 1880 in the UK (Swan), incandescent light bulbs were patented
      • So, now there was a means to generate electricity on a large scale 24 hours a day and a practical use for that electricity in every home, office, and factory: lighting
    • In America, the focus was on direct current (DC) - where the current always runs from the source (generator or battery) to the user
    • In Europe, alternating current AC was favored - current that would reverse directions constantly
      • AC won
    • Serious electrification of cities started in the US in 1905 and, by 1930, 70% of urban households were electrified
      • In 1930, only 10% of rural America was electrified
      • Low population density lead to slow penetration of the grid into rural areas because privately- owned electric companies thought it too costly
    • 1935 - REA (Rural Electrification Administration) was established by the US government
      • REA established rural non-profit cooperatives as the means of electrification
      • Roosevelt initiative - opposed as unfair competition with private enterprise
      • 1940 - rural electrification at 33%
  • Electrification of the World (2009 data, percent of total population)

Region
Urban
Rural
Overall
North Africa
100
94
99
Sub-Saharan Africa
60
14
31
China and East Asia
96
86
91
South Asia
69
60
68
Latin America
98
74
93
Middle East
98
72
89
Other Developing Countries
91
63
75
World (both Developed and Developing) 
94
68
81
  • Proportion of those served by the grid is always less in rural areas
    • Low population density means every user must get more wire which increases both cost to set up wire and to maintain it
  • Proportion of those with access to the grid varies in different regions
    • In sub-Saharan Africa, the rate of electrification has been lower than the growth rate, so that the proportion served by the grid has been declining

A large portion of the energy sector is devoted to supplying consumers with electricity to run electrical appliances, lighting, heating, and so forth.

Power Plants

  • Most commercial power plants are described by the type of primary energy used to operate the turbine-driven generators.
    • Fossil fuel plants boil water and use the steam pressure to drive the turbines
      • These can be coal, oil, or natural gas
      • Natural gas can sometimes be liquefied after being pumped from wells
        • Liquids are safer to transport and store
    • Nuclear Power Plants are similar to Fossil Fuel Power Plants in that they heat a fluid and use the heated fluid to drive a turbine
    • Waste-fueled Electric Power Plants burn garbage to generate electricity
      • Must be very careful to remove toxic materials from their emissions as it is difficult to predict just what will be in the waste burned
    • Hydroelectric Power Plants use the pressure of water to drive the turbines
    • Solar Power Plants directly convert photons of light into energy
    • Geothermal Power Plants heat the water with heat from below ground
    • Wind Farms concentrate wind turbines in a single location and combine their individual outputs
  • Most utilities that generate electricity must have a larger generating capacity than is actually needed
    much of the time.
    • The surplus capacity provides a reserve to meet fluctuation in peak demand or to cover repair and maintenance downtime for power plants or portions of the electrical grid.
    • Brownouts and blackouts can occur that disrupt society if supply of energy exceeds demand.
      • Blackouts are total loss of power for a group of users
      • Brownouts are drops in voltage for a group of users (the lights are less bright, the heater will not get as  hot, your toast will take forever to get toasty)
        • brownouts can be as bad as a blackout for industry and for the operation of critical infrastructure (water pumps, medical equipment,  etc.)
  • Annual electric generation has climbed steadily since 1980 and the proportion from fossil fuel burning has remained steady

Hard and Soft Technologies

  • Hard technologies: large-scale plants, which are complex, expensive, and centralized
    • Large power plants fueled by fossil fuels, water, or atomic energy
    • Some “renewable” hard technologies: Large scale solar plants, windmill farms
  • Soft technologies: small-scale plants and applications, which are local, and usually more environmentally friendly than hard-energy technologies.
    • active and passive solar on a single building, individual windmills, solar panels for individual lights, etc.
    • Most electricity is generated by large “hard tech” plants

Fossil Fuels

The fossil fuels (coal, oil, natural gas) formed over geological time from the remains of plants and animals buried under layers of sedimentary rock.

  • People are consuming fossil fuels millions of times faster than they are forming, so we consider these to be Non-Renewable.

Have fossil fuel supplies increased or decreased over time?

  • Known reserves may increase if we discover more deposits
    • The total supply may decrease even as more deposits are found if we use the resource faster than we add to the reserves
  • How long the reserve lasts is related to both the total amount of resource that can be recovered and the rate of rate of energy use.
    • If you want it to last a long time, assume "at current rates of use" and you will predict a long period before the resource is depleted
    • If you assume a constant, positive growth rate, then the time-to-depletion will be much shorter (even for modest growth rates)

Oil

Regional oil production and consumption

Region
Production (%)
Consumption (%)

Middle East
30
8
Russia
15
5
Africa
13
4
US
10
23
Asia and Oceania
10
29
Central and South America
9
7
Canada and Mexico
8
5
Europe
6
19

Just how much of it is there?

  • Must be a finite resource!

Four components of this question:

  • What we have used up to now?
  • What we know about (Proven Reserves)?
  • What we have not yet discovered?
  • What we will never discover or never use?

Hubbert’s Curve - M. King Hubbert devised a way to use the first two to predict the last two

  • Uses historical production and proven reserves to predict future production
  • Bell shaped curve
    • Curve first rises due to
      • new discoveries
      • new infrastructure
    • Curve peaks and declines due to
      • Reduced discovery rate
      • Resource depletion
  • Implications of Hubbert’s Curve
    • We must expect to live with declining production of some resources
      • Economic systems based on continuous growth (exponential growth) will fail in a world of declining resource
    • What is the interaction between price of oil and the implications Hubbert’s Curve
      • Price may increase the incentive for
          • Discovery
          • Efficiency
          • Conservation
        • But it will not increase the amount of the resource
      • Oil Production and Price
        • Oil production has been much more steady than price
        • Market is not supply and demand but anticipated supply and demand
      • Oil Demand and Discovery
        • In economics, supply is usually tied to demand, such that greater demand will result in greater supply
        • Oil demand has continued to increase but discovery of new oil has declined, not increased.
          • The gap is ever growing as we now consume more than we discover each year.
    • What is the interactions between technology and the implications of Hubbert Curve?
      • Technology may increase:
          • Rate of discovery
          • % of resource that is useable
          • Efficiency of resource use
        • But these will not increase the amount of resource
      • Technology may provide a substitute for the resource (Nuclear Fuel or Wind for Coal and Oil)
        • This is how technology can alter the outcome
        • However, the substitute may also be governed by Hubbert’s curve
          • One effect of Hubbert's curve is that, as easily extractable oil (lighter, more runny) becomes less available, petroleum once too expensive to extract and refine becomes cost-effective
          • There has been a marked rise in extraction of thick,  bituminous petroleum since we passed the peak in the Hubbert Curve for  world oil production
    • Hubbert’s reasoning can be applied to any finite resource and there are peak curves for:
      • Natural Gas
      • Coal
      • Phosphate (fertilizer component)
      • Nuclear fuel
      • Transition metals (Cu, Ni) and Precious metals (Au, Ag)
      • A modified form of the curve can be applied to renewable resources IF:
        • the resource is being overexploited in that it is being harvested much faster than it is being renewed
        • Fresh Water and Oceanic Fish are two examples of over-exploited resources

Coal

Coal is much more abundant than oil and more evenly distributed throughout the world.

  • Mostly used to produce electricity (some for steel production and some for heating)
  • There are four kinds of coal that make up a series from most plant-like to most altered by pressure, heat and time
    • quality is related to how much energy one can get per kilogram burned and how much impurity is present
    • Peat - decayed, pressed plant remains (not usually used for electricity production)
    • Lignite - low-quality coal, soft and often brown
    • Bituminous Coal - mid-level quality, soft, contains a tar-like material called bitumen
    • Anthracite - highest quality but almost all has been mined (only PA mines it in the US), black, hard and shiny
  • Coals origins
    • Coal comes from almost all geological periods (even some Pre-cambrian, which must be from algae since plants had not yet evolved)
    • Carboniferous Coal - Eastern US
    • Permian coal - Russia and Australia (which also has coal from the mesozoic)
  • Major coal producers are China (48%), US (15%), India (6%), Australia (6%), Indonesia (5%) and Russia (5%)
  • Major coal reserves are in US (22%), Russia (14%), China (13%), Australia (9%), India (7%) and Germany (5%)
    • In the US, there are five coal regions (Eastern, Gulf, Interior [IN, IA, IL, MO], Rocky Mtn, and North Plains

The world’s known coal supply could last about two hundred years at current consumption rates

  • much less time if it is used as a replacement when the oil resource is exhausted.
  • time-to-depletion is also shortened by increased demand for electricity that is met by increased production

Why the internet is a dangerous place for the unaware

  • "It has been estimated that there are over 847 billion tonnes of proven coal reserves worldwide.  This means that there is enough coal to last us around 118 years at current rates of production.  In contrast, proven oil and gas reserves are equivalent to around 46 and 59 years at current production levels.”
    • 2011 World Coal Association   http://www.worldcoal.org/coal/where-is-coal-found/
  • The webpage defines “proven” but never indicates how the time until depletion is calculated.
    • Are they allowing the rate of consumption to grow?
    • Would you accept their figure of 118 years if they do not assume increasing demand?

Natural Gas

Mixture of volatile hydrocarbon molecules

  • Methane most common, ethane second most common
  • Source for propane, butane, pentane, hydrogen sulfide (can be processed into sulfur), and helium

Formed naturally in two ways:

  • Thermogenic gas (in deep rock where organics are converted into simple, reduced hydrocarbons under great heat and pressure)
    • Thermogenic gas deposited underground
    • Trapped in porous rock under impermeable rock layer
    • Often (not always) found with oil or coal deposits
  • Biogenic gas (metabolic product of a prokaryote from anaerobic respiration)
    • Biogenic gas is generated in:
      • Wetlands
        • Flooded soils have little O2 so decomposition goes anaerobic
      • Landfills and Sewage Sludge
        • Sludge is the product of sewage treatment
      • Cows
        • Gut symbionts produce methane

Town Gas:

  • Gas produced from coal (by heating in closed ovens -- not economically feasible today)
  • Cities would build a gas-plant and pipe the gas into homes for cooking and heating

Natural gas is obtained by

  • Collecting it from wellheads and piping it to customers
    • First processed to remove contaminants (H2S, mercury, water, CO2, N2 and others) and separate valuable minor components
  • To release the gas from rock with very small pores, some wells are first “fracked”
    • liquids (water, mostly) are pumped at very high pressure into the well to fracture the rock, releasing the gas
    • at least some fracking fluids must be pumped back up to facilitate release of the gas
  • Natural Gas Plant Liquids (NGPL)
    • Higher molecular weight hydrocarbons are turned into liquid fuels
    • Much NGPL is used to dilute the bitumen and other viscous, high density petroleum that are taking the place of the easy to extract (and now mostly gone) lighter, liquid crude oil most of us think of when we think of oil
      • Imagine a "gusher", a well spouting oil - much of the "oil" now pumped is too thick to gush
      • NGPL is a source of cheap light-weight hydrocarbon that can be used to dilute the thicker oil well products so that they will flow through the pipelines used to transport petroleum to refineries
        • The mixture of the tar (properly called bitumen) and NGPL is called Dilbit (DILuted BITumen)

Environmental Hazards associated with Natural Gas

  • methane is a more potent greenhouse gas than CO2 so any release of gas into the atmosphere contributes to increasing the greenhouse effect
  • natural gas combustion produces CO2 the primary greenhouse gas
  • natural gas contains contaminants that are pollutants both before and after burning
  • H2S and derivatives (mercaptans), siloxanes, mercury, and radon
  • H2S is poisonous, radon is radioactive
  • Burning CH4 oxidized H2S into SO2 and SO3, which combine with H2O in the atmosphere and form Sulfuric and Sulfurous Acid and so acidify rain and lakes
  • fracking fluids contain pollutants and must be treated before release

Methane Hydrates / Clathrates

  • Formed from water and methane at high pressure and low temperature
    • Methane is trapped inside of the ice crystals (not always normal ice crystal structure)
  • Found in Permafrost and in Marine sediments at ocean bottom
    • Known Hydrate Deposits are off of coasts throughout the world
    • Huge amount of methane (probably biogenic) trapped in these deposits (may be more than is in rock deposits)
      • Some estimates are that 2/3 of all carbon in oil, coal, and natural gas is in these methane clathrate deposits!
    • Some see it as a potential resource
    • Some see it as a potential hazard because, if released, methane is a more potent greenhouse gas than CO2

Concerns about Fossil Fuels

  • Energy consumption raises two basic concerns:
    • How will we power our future as we deplete current energy sources?
    • How can we minimize energy-related environmental degradation?
  • Historically, energy-related problems have been addressed by using more energy.
    • A more productive approach to these problems may lie in reducing demand by increasing efficiency and/or by conservation.
  • Efficiency of energy extraction for ways of generating electricity
    • Hydro reaches over 90% efficiency
    • Of the fossil fuels, natural gas is best (55%),
    • Wind similar to fossil fuels
    • Solar now near 20%

the ANWR controversy 

Arctic National Wildlife Reserve

  • 19 million acres
  • Largest wilderness area in the US
  • Important for preservation of several species, including a subspecies of Caribou (Porcupine River)
  • Canada has large wilderness areas bordering on ANWR
  • Drilling is proposed for the “1002” Area on the coast of the Arctic Sea

What would we get from drilling?

  • Hard to estimate at the present but
    • 1998 estimates were between 5.7 and 16 billion bbl (4.3 to 11.7 on Federal Land)
    • 2010 estimates of oil from nearby coast were far under previous estimates as many test wells produced natural gas, not oil
  • Productivity, if it were opened to exploration and drilling now, would begin in 2018, peak (using the mean reserve figure) in 2027.
    • Production at peak would be 0.78 million bbl/day
    • In 2010, US DOE says, we produce 5.5 million bbl/day and consume 21.3 million bbl/day (the gap is filled by imports and other liquid fuels)
  • So, ANWR will never be more than 3.6 % of US need (6.8% for highest reserve estimate)

What about gas prices?

  • Gas prices are set by an international market, not the US market
    • ANWR production will never be more than 1.2 % of global consumption (high estimate) and could be less if demand increases faster than predicted
  • So, it would mean, at today’s $3.60 per gal price, a difference of 2.8 cents per gallon, assuming 65% of gas price is due to oil price

the Future of energy production

  • At present, the environmental impact of our energy use is straining—and perhaps has exceeded—the capacity of natural systems to maintain themselves.
    • Reducing the energy-induced environmental destruction will require reducing energy consumption by increasing efficiency and increasing the use of alternative energy sources that reduce the environmental impact of energy production.
  • The Federal Government subsidizes energy sector industries
    • This makes price a poor predictor of future contributions from various energy options
      • Market economics may not find the optimal solution to the question of where we should get our energy as:
          • price in the market now only reflects production and distribution costs, not environmental costs
          • subsidies distort prices
    • Distribution of subsidies in 2002 to 2008
      • Fossil fuels:
        • $72,500,000,000 (72%) -
            • $2,300,000,000 (3%) for environmental cleanup efforts (carbon capture and storage)
            • $70,200,000,000 (97%) for tax breaks and other support
      • Renewable energy
        • $29,000,000,000 (28%)
          • $12,200,000,000 (28%) for solar, wind, geothermal, etc. support
          • $16,800,000,000 (28%) for corn ethanol support
    • All in all, government support for sustainable, renewable, non-food crop energy is only 12% of total subsidies for energy
  • Governments (many national governments, US federal and some US states) are debating taxing various energy sources for their particular environmental costs
      • Oil spills, land and water contamination by coal mining, carbon dioxide emission, acid rain, etc.
    • Normally, environmental costs are not paid by the energy consumer alone but by everyone
      • Environmental impact Taxes reflect the environmental costs and should be spent for remediation
    • Environmental impact taxes are a means of putting burden on the consumer, so that the consumer will choose among energy sources based on the total cost of the energy from each source
      • Tennessee already has this sort of scheme in place at the gas pump but not for assessing the cost of environmental impact
        • Gas tax is to pay for building and maintaining roads
        • Public roads are a cost to all and our gas tax in meant to shift some of the burden of paying for them from the general public to those who use Tennessee's public roads
      • Environmental Impact Taxes use the same logic as the "user-pays" gas tax
        • Carbon tax is the most commonly discussed but it is only a specific example of a general principle
      • Tennessee’s gasoline tax (From http://www.tdot.state.tn.us/gastax)
        • 21.4 cents per gallon (20 gasoline tax + 1.4 special petroleum fee)
          • Yields $668.9 million per year
        • How the tax is divided
          • 7.9 cents, or $246.8 million, goes to cities and counties
          • Approximately .7 cent, or $22.1 million, goes to the State General Fund
          • Approximately 12.8 cents, or $400.1 million, goes to TDOT
            • The $400.1 million is included in TDOT's total state revenue of $874,300,000 and is used in three basic ways to accomplish TDOT's mission:
              • Basic operating costs
              • Highway maintenance contracts
              • Resurfacing, bridges, major reconstruction, new construction, consultant contracts, right-of-way purchases, and to match federal funds
    • Currently, most Gas Taxes in various countries and states are not Environmental Impact Taxes

Why We Must Stop Burning Fossil Fuels (from textbook)

  • "Whether or not we are in danger of running out of fossil fuels, we must curtail their use
  • The use of coal, oil, and natural gas facilitated the development of modern industrialized society but it has also created environmental havoc on a global scale
  • While the duration of existing and possible reserves is unpredictable, the major concern is the large-scale environmental degradation that using fossil fuels creates."

Politics and Energy

  • This is another "wedge issue" in our political life and, as such, you should be very skeptical of many websites with material on the subject of energy and energy policy
  • One small example:
    • A comparison of the change in US per capita and Chinese per capita energy use
    • One site has a graphic of US versus Chinese usage over recent years
    • If one does not look at the axis labels closely, one might think that the average Chinese citizen
      now consumes more oil than the average American
    • But a graph with both rates are on the same scale shows that, although Chinese per capita usage has gone up recently, US per capita usage is far, far more than Chinese per capita usage
  • So, why the scare tactics when the average Chinese citizen sips oil and the average US citizen gulps it?
    • The size of China's population means that their total demand has exceeded US demand
    • So China is now competing for resources with the US and has replaced Japan as the “Eastern Economic Threat”

Environmental Impact of Coal (an example from our textbook)

  • Using more coal can increase air pollution
  • Coal emits 25% more CO2 than an equal amount of oil
  • Coal emits 80% more CO2 than an equal amount of natural gas
  • Burning coal releases sulfur dioxide and nitrogen dioxide, the major contributors to acid rain
  • Environmental Impacts of the Coal Fuel Cycle (see diagram in textbook)

Energy Use Impacts

  • The fossil fuels (oil, coal, and natural gas) are the major source of air pollution, acid rain, and greenhouse gases.
  • Mineral extraction of fossil fuels and uranium, and dam construction for hydroelectric power, both create major environmental destruction
  • The conventional fossil fuels, upon which we rely heavily, are nonrenewable and are being depleted rapidly.

Nuclear Power

Nuclear Power (from textbook – pre Japanese tsunami disaster at Fukushima)

  • Nuclear power supplies about 6.5% of the world’s commercial energy, but supplies a much larger percentage of electrical generation in some industrial countries.
    Growing public concerns about safety, and the high cost of nuclear power, are changing the earlier enthusiasm for nuclear-generated electricity in many countries.
  • Since 1978, there have been no new nuclear plants ordered in the U.S. but other countries like China and India have continued developing their nuclear capacity.

Principles of Nuclear Power by Fission

Both the fission and fusion of nuclear power involve rearranging the structure of atoms.

  • Fission is the splitting of an isotope of a heavy element into daughter products (smaller atoms) with the release of energy.
  • All commercial nuclear energy generation is by fission.
  • Fusion is the joining of isotopes of a light element into a heavier element with the generation of energy.
    • The sun generates heat and light by fusion.
    • Some nuclear weapons use fusion reactions but controlled fusion is still in the development stage and has been for 50 years.

Nuclear Radiation

  • Radioactivity comes from Radioactive Decay of unstable isotopes
    • Light is radiated energy, so what do we mean when we speak of atomic radiation?
  • Unstable atomic nuclei change to become less unstable or stable (Second Law says they must)
    • There are three general types of radiation (Alpha [],Beta [], and Gamma []) related to the three general causes of instability:
      • Instability due to excess of protons resulting in too much repulsion within nucleus
        • Alpha () emission is the ejection of a helium nucleus (two protons and two neutrons)
        • there are other, rarer, forms of proton loss
      • Instability due to unstable neutron:proton ratio
        • (Beta, ) – electron (-particle) emission leaves behind a proton, which changes the element to which the atom belongs
        • (Beta) – positron emission
        • (Beta) – electron capture when an electron orbiting a nucleus is captured and fused with a proton to form a neutron
          • note: no radiation produced but a proton is converted into a neutron so the atom becomes a different isotope of the element to which it belongs
        • there are other, rarer forms of ratio adjustment
      • Instability due to excess energy in nucleus
        • Gamma () emission releases a very high-energy photon (only cosmic rays have more energetic photons)
  • Different kinds of radiation (emissions) have different effects
    • Size, charge, and weight of particle determine how likely it is to interact with (hit) another atom
      • the addition of the collision energy (or absorption of the gamma photon energy) can break bonds between atoms in molecules (like DNA), causing metabolic damage (this is the danger of radiation)
    • Different types of radiation have different powers of penetration
      • Alpha particles will all hit atoms in a sheet of dense paper,
      • beta particles can penetrate paper but a thick layer of plastic will stop them
      • gamma photons penetrate most matter an only a thick layer of dense material will absorb them (lead is very dense)
    • Once ingested, danger reverses!
        • Alpha particles emitted in the stomach will cause havoc in the lining of the stomach
        • beta particles emitted from material in the stomach will penetrate deeper into the body
        • gamma photons emitted from material in the stomach will most probably pass out of the body without doing any damage
  • Radiation exposure
    • An average US citizen receives, during his or her life, potentially damaging radiation from these sources:
      • 50% of radiation from radon in the environment
      • 15% from medical treatment or diagnosis
      • 13% from untraceable gamma sources
      • 12% from cosmic rays (more damaging than gamma)
      • 10% from ingested radioactive isotopes
      • less than 1 % from all other sources (fallout, commercial products, improperly disposed of radioactive materials, etc.)
    • These % can change radically for individuals caught near a nuclear disaster
  • Radioactive decay happens as a series of emissions
    • exact steps are different for different fissile elements but lets look at 235U92, the most commonly used isotope in both bombs and reactors
      • 235U92 starts not as uranium but as plutonium (235Pu94 , [24,300 yr])
      • Pu - alpha emission to Uranium (235U92, [700,000,000 yr])
      • alpha decay to Thorium-231 (231Th90, [25 hours])
      • beta decay to Proactinium-231 (231Pa91, [32,000 yr])
      • alpha decay to Actinium-227 (227Ac89, [21 yr])
        • there are two pathways from here but we will list only one
      • beta decay toThorium-227 (227Th90, [1.9 days])
      • alpha decay to Radium-223 (223Ra88, [11 days])
      • alpha decay to Radon-219 (219Rn86, [3.9 seconds])
      • alpha decay to Polonium-215 (215Po84, [2 milliseconds]) - two paths again, only one described
      • alpha decay to Lead-211 (211Pb82, [36 minutes)
      • beta decay to Bismuth-211 (211Bi83, [2.2 minutes]) - two paths again, only one described
      • alpha decay to Thallium-207 (231Tl81, [5 minutes])
      • beta decay to Lead-207 (207Pb82, )
    • Lead-207 is stable
      • some of the decay steps above also release gamma radiation
      • the numbers in square brackets are half-lives, the amount of time it takes for half of the atoms of an isotope to decay

Fission

  • Fission is triggered by a neutron colliding with and splitting the nucleus of a heavy atom like Uranium-235
    • 235U92 is a rare isotope (the most common type is 238U92)
  • The nucleus splits, releasing three neutrons, daughter atoms (which can be radioactive), and a large amount of energy.
    • The two smaller nuclei formed are Barium (142Ba56) and Krypton (91Kr36)
    • the energy we can use to heat water and generate electricity
      • [note - I can't write the atomic number and atomic mass to the left of the symbol as is usual so I am putting the atomic mass to the right as a superscript and atomic number to the right as a subscript
  • A nuclear chain reaction occurs when the emitted neutrons hit other nuclei.
    • Since there are three neutrons emitted when U235 fissions, three more U235 will split, emitting nine neutrons, splitting nine U235 and releasing 27 neutrons, and so on and so on - this is a positive feedback loop.
    • A chain reaction will not happen if the neutrons hit other nuclei that do not emit neutrons when hit
    • These other materials may absorb the neutrons without splitting (more on this later) and so, the density of fissile nuclei controls whether or not a chain reaction begins
    • the fission of a nucleus must, on average, produce the fission of more than one other nucleus for a chain reaction to happen
  • Unstable and stable nuclei still have to “ climb an energy hill" before the nucleus will fall apart (like an energy of activation for chemical reaction)
  • Nuclear Fission and Radioactive Decay are not the same thing.
    • Nuclear Fission produces no alpha, gamma, or beta radiation but but does release high-speed neutrons as radiation (very damaging)
    • Radioactive decay is a spontaneous result of intra-nuclear instability
    • Fission depends on a collision with an external particle
  • Neutrons, since they are electrically neutral, have the penetration power of gamma radiation

Controlling Fission

  • To induce a sustained nuclear chain reaction, one must increase the probability that excess neutrons from one fission event will cause other fissionable atoms to split.
    • Moderators like graphite, beryllium, and water slow the speed of neutrons without absorbing them.
    • A modern nuclear reactor core contains fuel, a moderator, and control rods (cadmium or boron) to permit a sustained but controlled chain reaction.
  • Light Water Reactor
    • The water of the primary system, which serves as a moderator and may become radioactive, is entirely housed in the containment vessel.
    • The secondary water system is heated by the primary water loop and produces the steam which drives the turbine generator.

Nuclear Fusion

  • The Sun generates heat and light by fusion.
    • Fusion is the result of gravity pulling hydrogen into center of Sun, where it is squeezed together so tightly, fusion occurs
  • Some nuclear weapons use fusion reactions
    • Fusion in bombs is initiated by conventional explosives surrounding fusible material the force the hydrogen atoms together
    • By colliding deuterium and tritium, a fusion of the separate nuclei (helium) occurs, releasing a neutron and energy
    • Extremely high temperatures and pressures are needed to fuse the nuclei of light elements.
    • The first artificial reaction was attained on Earth in 1954—with the detonation of the first
      hydrogen bomb.
  • Controlled and sustained fusion is still in the development stage and not yet economically feasible as a commercial energy source.
    • Fusion power plants must overcome some problems
      • How to initiate the fusion
        • Lasers have been suggested as a means of initiation (heating and compressing)
      • How to contain and control the fusion
        • Magnetic fields have been suggested as a means of containment
  • Some see fusion as an ideal energy source because:
    • We are not likely to run out of fuel
    • Fusion does not produce fissionable materials that could be used in bombs
    • The high temperatures generated by fusion could be used to vaporize all waste materials into their component atoms

Advantages and Disadvantages of Nuclear Power

  • Extracting and processing uranium for use in nuclear reactors has several environmental impacts: mining, tailing production, and contamination of land and water by toxic metals and radioactive nuclides.
    • Uranium resources, like fossil fuels, are nonrenewable and high-grade ore sources are being depleted.
  • It is difficult to determine what our nuclear resources are as exploration has not been extensive.
    • Breeder reactors (not used in the US) can extend the life of fuel by 60 times by “ breeding” more fissile nuclei than the number of nuclei that actually undergo fission.
      • Ratio of nuclei that fission to those produced can be 1 to 1.8
      • U-238 has 92 protons and can capture another neutron (from the fission of U-235) to become U-239
      • U239 undergoes two successive beta decays, and each one converts a neutron into a proton (and the ejected electron)
        • The first beta decay changes U239 into Np239 (Neptunium)
        • The second converts Np239 into Pu239 (Plutonium)

The Safety Record of Nuclear Power (from the textbook, amended by me)

  • Nuclear power generation has thus far proven to be the safest form of large-scale power generation by some measures.
    • However, “Black Swan Events” (catastrophic failures) make nuclear power very risky
  • The book says that "The economic and health impacts of nuclear power are lower than the impacts from coal-fired power plants."
    • this is so if you consider carbon emissions but it is a very broad statement and I don't know that I agree
    • If Chernobyl has increased cancer rates for millions and caused many thousands of deaths, it is hard to see nuclear power as significantly better than any other non-renewable resource
  • Nuclear Plant Accidents
    • Five nuclear cores have undergone total or complete meltdowns
      • One at Three-Mile Island in PA
      • one at Chernobyl in the USSR (now in the Ukraine)
      • three at Fukushima, Japan
    • Chernobyl
      • Operator error caused the power plant explosion at Chernobyl, the worst nuclear disaster so far. (remember that your text was written before Fukushima)
      • The supervisor of the Chernobyl damage control team suggested that perhaps 35 million people were damaged by high levels of radiation following the accident.
      • How many died at Chernobyl?
        • 2 died in the explosion
        • 237 suffered from Acute Radiation Sickness and 28 died as a result
        • 29 died as a result of other causes related to the disaster
          • Estimates for the number of cancer deaths from exposure to the released radioactive materials range from 9000 to 985,000
    • Three Mile Island
      • The Three Mile Island accident in the U.S. (triggered by a combination of operator and design errors, a stuck valve, and faulty sensors) produced much less damage.
    • Fukushima
      • No one worried about tsunamis until Fukushima
        • The nuclear power plant there was designed to withstand earthquakes but not tsunamis
      • This lead to two disastrous situations
        • The storm walls protecting the plant from waves were too small
        • The gas-fueled generators needed to supply electricity to run the plant safely during an emergency were put into the basements
      • When the tsunami came (generated by an off-shore earthquake) the flood walls were topped and the water ran into the basements so that there was no way to control the nuclear reactors
        • uncontrolled, they began to heat up and to generate hydrogen gas, which eventually exploded and worsened the disaster
      • eventually, water was pumped into the reactor cores to moderate them and reduce the heat output to manageable levels
        • those who restored the control risked their lives to do so
        • the event was close to becoming a melt-down, where such heat is generated that the nuclear fuel is expelled over a large area and into the air

Drawbacks of Nuclear Power

  • There are two main technical drawbacks
    • 1. resources need to extract uranium, building plants, and dealing with the pollution generated
    • 2. safely handling the radioactive waste.
  • Enormous amounts of energy, land, and materials must be used to build the plant.
    • More resources are used to prospect for, mine, and process nuclear fuel
  • routine operation creates thermal pollution.
    • Cooling the hot water produced by the plant can warm nearby rivers and lakes
  • After 30 to 40 years, an aging nuclear power plant must be decommissioned, another energy and resource intensive operation.
  • There is still no long-term, satisfactory method for disposing of the radioactive wastes generated by nuclear power plants.
  • Radiation
    • Radioisotopes or radionuclides are unstable atoms that give off radiation while undergoing spontaneous disintegration.
    • Radiation will affect any atoms or molecules it encounters.
    • Rapidly growing and dividing cells are usually most affected by radiation.
    • There is no “threshold” of exposure necessary to produce potentially deleterious results.

Safer Nuclear Reactors

  • The typical nuclear reactor is very large and complex.
    • This complexity makes them expensive, difficult to build, and prone to error in construction and operation.
  • The larger the reactor, the larger the potential catastrophe if something malfunctions.
  • Designs to minimize these concerns include:
    • Smaller scale
    • Passive safety systems
    • Modular design

Nuclear Waste Disposal

  • Although massive amounts of radioactive wastes have been generated since the 1950s, there is still no
    satisfactory plan for disposal.
    • Most high-level wastes are currently stored “temporarily” on the reactor site in pools of water.
    • Low-level wastes are buried in shallow landfills.
  • There has been a geometrically growing accumulation of nuclear waste and steady growth in the rate of production of waste.

Disposal Problems

  • Many reactor sites are running out of “ temporary” disposal space.
    • Safe permanent disposal requires:
      • Perfect containment with no leakage
      • Guarding to prevent political or terrorist diversion for potential weapon use
      • Secure transport to a permanent repository
  • Proposals to dispose of waste include:
    • Rocket loads of waste launched into the sun
    • Deep sea burial
    • Burial in Antarctic glaciers
    • Burial in stable geologic zones

Decommissioning Nuclear Reactors

  • Exposure to high temperatures and radiation bombardment limits the life of reactor components.
  • The probable life span of a reactor is between 30 and 40 years.
  • Recent 20-year operating license renewals for plants built in the 1960s will postpone decommissioning but may increase the risk of major accident.
  • The complete cost of decommissioning a nuclear power plant is still unknown.

Global Nuclear Power Today and in the Future

  • Around the world, new nuclear reactors are being built while older reactors are taken off line.
    • In North America and most of Europe, the active construction of new plants is virtually halted.
    • In Asia, many countries are still actively developing nuclear plant capacity.
  • June, 2011 - The Tennessee Valley Authority has agreed to investigate the feasibility of modular mini-nuclear reactors on the site of the abandoned Clinch River Breeder Reactor in Oak Ridge
    • Two of the new Babcock & Wilcox-designed "mPower reactors" by 2020.
      • Each of the new reactors would produce 125 megawatts of electricity -- about 10 percent as much as most conventional reactors -- and could be built in controlled factory conditions to cut production costs and ensure construction quality.
    • The mPower reactor technical details:
      • The mPower reactor will use 5% enriched uranium in fuel rod assemblies which are similar in design to those used in 1,000 MW plants.
      • At a price of $3,000/Kw, a single unit would cost $375 million
      • One of the intended uses of the mPower reactor is to “repower carbon-intensive plants where the transmission and distribution infrastructure is already in place. (coal to nuclear ? )
      • First units could be received by customers by 2018 and the reactor is be shipped by truck and rail to a site and installed below grade by skilled trades without complex training.

s22

Last updated April 18, 2013