Historic trend of increased energy use
Linked to population growth
Related to economic growth
Figure 3:Comparison of Per Capita Consumption in Different Nations
Seemingly insatiable energy needs of humankind
Endless search for a single energy supply
Looking for Mr. Goodenergy
Early civilization - destroyed forests
Industrialization - linked to coal, than oil
Promises of nuclear supremacy
Need an energy pie based on available sources
Based on Laws of Thermodynamics
Primary Energy Sources (found in earth)
Secondary Energy Supply (fuels for human use)
End Users (residental, commercial, industrial, transportation)
More steps, greater loss
Basic economic principles (energy costs & dollar costs)
Fuel Cycles (mining, processing, distribution, infrastructure, decommissioning)
Opportunity Costs, External Costs
Dependency on Fossil Fuels
Carbon dioxide levels are rising
Example of greenhouse gases, implicated in global warming
International implications (haves and have-nots)
Failure to explore and utilize renewable energy
Money & energy move in opposite directions
Need to assess both the financial and energy costs when making decisions about energy expansion
Energy is a global entity, and is directly linked with international economic growth
Energy Use Brings Environmental Damage
Greenhouse gas accumulation
Acid deposition
Air toxics (dioxins, mercury, PCBs, CFCs)
Nuclear accidents
Water pollution (acid mine drainage, oil spills, radionuclides, thermal loading)
Land damage (toxic waste disposal, petroleum leaks, forest loss, etc.)
Increased awareness of energy use
Develop sustainable practices
Utilize a mix of energy sources
Embrace a soft-path approach to energy technology
Analyze entire fuel cycle (including the cost of environmental pollution
Improve efficiency of extraction, distribution and usage practices
Utilize computers and other technologies for reducing heat losses
Cultivate an attitude of conservation
Maintain an open mind about renewable alternatives
Flow of Energy Resources, Commercial Exchanges
Sources of Primary Energy Supply for the U.S.
Mid-East Producers (conflicts, wars, interruption of supply, political and philosophical differences)
Saudi Arabia, Iraq, Iran, Palestine, Israel, Syria, Lebanon
Nigeria (source of "sweet" crude oil desired for refining into gasoline; major supplier for U.S. - dangers of political instability, environmental degradation, and extensive corruption in Nigeria)
Venezuela (political differences, price controls)
Canada - Hydropower Quebec supplying electricity to the northern U.S. and New England
Alaska - Impacts of pipelines in tundra regions (similar problems in Siberia, even worse) - questions of drilling in U.S. Arctic Reserve areas - melting of permafrost in northern regions
Increased global demand for fossil fuel supply (e.g., growing economies like China and India)
Struggles over who controls fuel supply (e.g., Russia and Ukraine, and the connection with Western Europe; Russia, Canada, U.S., Scandinavian countries sparring over Arctic resources)
Control over rare earth elements that are important in the manufacture of solar devices, wind turbines, electronic communication, military equipment, hybrid cars, etc.
Complexities of ocean drilling for gas and oil (likelihood of accidents and difficulties of mitigation and cleanup; multinational companies doing business worldwide; long-term damages affecting large areas of coastlines)
Domestic Issues (Fights over water rights for shale processing; pollution generated by coal processing and utilization; excessive lobbying by the energy industry with policy setting driven by secrecy and deal-making; relative roles of government subsidies of selected industries, and government incentives for changing the energy distribution system; role of stakeholder groups fostering or blocking different types of energy applications; and the economic dynamics of change and new directions for energy supply and efficiency standards)
How Do Systems Work?
Systems have structure and process energy
Components include input, throughput and output
Feedback loops exist which permit the system to make adjustments
Open systems depend on an outside source of energy
Energy transformations are not 100% efficient (Law of Entropy)
As systems use energy, entropy increases
Systems must gain negative entropy to compensate for entropy losses
Entropy includes energy losses, system deterioration, disorder and waste
Negative Entropy includes structure, order and energy availability
An Open System needs an excess of negative entropy
Net energy yield is the amount of energy remaining at end of process
Stable systems have a high degree of homeostasis
Operational Energy (enough energy to maintain an ongoing system)
Energy for Emergency Response to unexpected perturbances
Energy for Growth and Elaboration of system
As systems expand and become more elaborate, their structures change
Levels of organization increase and coordination becomes necessary
Information processes must be well developed
Usable information coding must be in place
Integration of system parts is essential
Open Systems have repetitive cycles of events that help the system function
Cycles in natural systems include daily and seasonal patterns
Examples: trophic relationships and reproductive patterns
Organizational systems feature cycles related to the complexity and stage of development of the system
Equifinality suggests that different systems can reach the same endpoint by following different pathways
Goal of an open system is to achieve optimal stability over time,
i.e., greater homestasis and negative entropy
More diverse systems tend to have greater chances for stability
Five Approaches
Enjoy conflict resolution
Bring diverse viewpoints into discussion
Challenge popular ideas
Can be argumentative
Good at brainstorming; innovative
Incorporate values and ideals into decisions
Sensitive to the viewpoints of others
Care about people and their needs
Can delay in making decisions
Excellent at bringing human issues into discussion
Like to get things done (shortest way possible)
Any method will do; just use one
Inventive, when necessary
May act rashly, without due consideration
May overreact in the face of delays
Good contributors to problem solving
Likes to analyze numbers, facts
Good at organization and efficiency
May spend too long in collecting and reviewing information
Excellent at considering detailed information
Like to get the job done well
Value technical expertise and seek it out
Willing to make decisions based on valid information
May appear to be too "commanding"
Good skills in overseeing projects
SUMMARY
Synthesist, Idealist, Pragmatist,
Analyst, Realist
Photosynthesis - plants/algae can capture sunlight, converting light to chemical energy
Dependent on pigments like chlorophyll
Production of carbohydrates
Respiration - ability of living cells to convert carbohydrates to ATP units
Production/Consumption in Ecosystems (continued)
Formula for Photosysnthesis
(chlorophyll & sunlight)
CO2 + H20 ----------> C6H1206 + 02
Formula for Respiration
C6H1206 + 02 ----------> CO2 + H20 + ATP
World Energy Budget
Annual Insolation (equivalent to 15,000 times the 1990 world energy supply)
30% reflected back to space (albedo)
50% Absorbed, converted to heat and reradiated
20% creates wind, powers water cycle and drives photosynthesis
Trophic Dynamics
Ability to photosynthesize
Algae and plants (some bacteria)
Usually small in size; exist in large numbers
Base of food chains
Responsible for primary productivity
Generate carbohydrates for respiration
Organisms that consume plants or algae
Usually small in size
Examples: Zooplankton, snails, cows, horses, insects, zebras, ciliated protozoa
Contribute to secondary productivity
Consume herbivores
Usually larger in size
Examples: wolves, lions, sharks, reptiles, hawks, shrews, spiders, amoebae
Many layers of carnivores in an ecosystem
Contribute to secondary productivity
May act as herbivores or carnivores
Varied feeding habits (versatile consumers)
Include humans, pigs and many insects
Contributed to secondary productivity
Detrivores (consume decaying material)
Very important to detrital food chains; recycle nutrients
Found in large numbers in forest litter, marine and aquatic benthos
Examples: fungi, some invertebrates, bacteria, protozoa
Grazing food chains based on producers (photosynthesis)
Detrital food chains based on detrivores (breaking down detritus and wastes)
Grazing food chains important in marine and aquatic ecosystems
Detrital chains important in forest litter
Trophic Pyramid
Show feeding patterns
Smaller to larger size
Many to fewer in numbers
Levels vary from one ecosystem to another
Energy can be defined as the "capacity to do work"
(Also see handout on class definitions of "energy")
Work = force x displacement
W = F x d
Measurement Systems
Length-Mass-Time Systems
British System: force in pounds and distance in feet; energy (work) in ft-lbs
Metric System (MKS): force in Newtons (N); distance in meters; energy in joules (J)
Metric (cgs): force in dynes; distance in centimeters; energy in ergs
Concepts & Terminology
All systems need energy to exist
1st law: Law of Conservation of Energy/Mass
total amount of energy in a closed system remains constant
energy is neither created nor destroyed
energy can be converted from one form to another
2nd law: Law of Entropy
energy conversions are not 100% efficient
using energy changes the energy into a degraded form (useless to system)
Law of Entropy - Results in an energy loss to the system in which transformations occur
The more steps in a conversion process, the lower the efficiency of the entire process
Electricity generation (~30%)
Involves conversion of fuel for heating water to produce steam to turn a turbine in a magnetic field, thus producing a flow of electrons
[See Spreng, Net Energy Analysis readings - Chap. 5, 12]
Ek = ½ mv2
M(mass) = measure of an object’s resistance or inertia to being set in motion (slug, kg, gm)
V (velocity) = distance traveled/time (ft/s, m/s, mile/hr, km/hr)
Ft-lb = weight of mass x distance moved
m (mass) = measure of an object's resistance or inertia to being set in motion;
(not dependent on location)
British System: slug, Metric System: kg or gm
Equivalency: 1 slug = mass accelerated at 1 ft/sec2 by a force of 1 lb = 14.6 kg
v (velocity) = distance traveled/time; (ft/s, m/s, mile/hr, km/hr)
Ft-lb = weight of mass x distance moved (1 pound x 1 foot)
Joule = Force of 1 newton displaced 1 meter in the direction of the force (kg*m)
Erg = Force of 1 dyne displaced 1 cm (g*cm)
Newton = Force required to displace 1 kg the distance of 1 m/s2
Dyne = Force required to displace 1 gm the distance of 1 cm/s2
Mass versus Weight:
Mass is the measure of a body's resistance to acceleration
Mass is proportional to weight
Mass is independent of position but dependent on its motion in respect to other bodies
Weight on earth is the force with which the earth pulls on a mass
Units of force: Pound or Newton
Weight (force) = (Mass) x g
g = acceleration of a freely falling object due to the gravitational field of the earth
32.174 ft/s2, or 9.8 m/s2
1 Pound = Weight of a standard 1 pound mass subject to the earth's gravitational force
Energy of position (e.g., mass at some height above the ground; because of its position, it is capable of doing work)
Ep = mgh [mass x gravitational force x height]
Will gain kinetic energy if it falls back to earth
Other examples (spring, pendulum)
Based on Theory of Relativity (Einstein)
E = MC2 [E = energy; M = mass; C = velocity of light (3x108 m/s)
When the mass of some system is reduced by an amount, delta M, then an amount of energy is released
When certain chemicals combine (or break apart), energy can be released, usually as heat, expressed as Calories
Comparative Examples:
Coal Burning [C + O2 = CO2 + 95 kcal/mole (mole is gram molecular mass = sum of atomic masses in grams, same as the number of protons and neutrons in nucleus)]
Sugar Combustion in Living Cells [C6H12O6 + 6O2 = 6CO2 + 6H2O + 690 kcal/mole]
Heat energy is not thought of in absolute terms but in terms of an amount of heat (delta Q) transferred into or out of a substance
When heat is added into some substance, two changes can occur:
(1) Increase in the internal energy (delta U), i.e., increased kinetic energy of the molecules, or increase in the temperature of the material
(2) Material expands and performs work on some external system (e.g., push a piston), and delta W (work) is performed
[delta Q = delta U + delta W]
Heat is traditionally measured as BTUs (British thermal units), or in calories (cgs system) or Kilocalories (MKS system)
British thermal unit = Amount of heat energy to raise 1 lb of water 1oF
Fahrenheit versus Celsius Temperature Scales [Tf = 9/5 Tc + 32] or [Tc = 5/9(Tf – 32)]
Calorie (cal) = Amount of heat energy needed to raise the temperature of 1g of water 1 degree Celsius
Kilocalorie (kcal) = Amount of heat energy needed to raise 1 kg of water 1oC
Mechanical equivalent of heat can be calculated
1 cal = 4.184 Joules
1 Btu = 778.2 ft-lb = 0.252 kcal = 1055 J
e.g., How many BTU of heat energy was added to the water if the temperature of 15 lbs. of water in a tank was heated by 10 degrees? What is the energy in joules?
Power = Energy (or Work)/ Time
1 Watt (W) = 1 J/s
1 Horsepower (HP) = 550 ft-lb/s
1 HP = 746 W = 0.746 kW
Applications of these terms
Vehicles (horsepower) – work performed
Appliances (kilowatts) – energy consumed
Electricity (kilowatt-hours, kwh)
Comparison of Power Units
1 kWh = 103 Watts x 3600 s = 103 J/sec x 3.6x103 s = 3.6 x 106 J
Ohm’s Law (accounts for resistance of a material to the flow of electrical current through a material)
I (amperes) = V (volts)/ R (ohms)
Important concept in electrical transmission (longer transmission distances results in resistance losses)
W (watts) = V x R
V (volts) = W (watts)/I (amperes) and W = VI
Represents the field of force associated with electrical charge in motion
Electronmagnetic Spectrum includes radio waves, microwaves, infrared radiation, light, UV radiation, electromagnetic fields, x-rays, and gamma rays
Most important source of energy (electromagnetic radiation from the sun)
Characteristics of waves
Wavelength (Greek symbol lamda)
Frequency (f) – measured in hertz (cycles/sec)
Amplitude (height of the wave)
Electron volts (eV) used for shorter wave radiation
Energy and power units of J and W are generally used
The eV (electron volts) is used for shorter wavelength radiation such as x-rays and gamma rays
British System (Pound, Foot, Second, British Thermal Unit or BTU, Horsepower, Watt)
Metric System (MKS or cgs)
MKS = Newton, Meter, Kilograms, Second, Liter, Kilocalorie, Joule)
CGS = Dyne, Centimeter, Gram, Second, Milliliter, Calorie, Erg)
Units are “convertibleâ€
Conversions occur regularly due to the global nature of the energy supply
Common Use of Measuring Units
Petroleum (Barrels-bbl; Million gallons/Day-mgd)
Coal (British tons-Ton; Metric ton-Tonne)
Natural gas (Therms, CCF)
Gasoline (Liters, Gallons)
Uranium (Tons, Tonnes, Grams, Kilograms)
Naturally occurring energy resources
Fossil fuel sources (coal, crude oil, natural gas, tar sands, oil shale)
Hydropower (waterfalls, tidal currents, wave action-primarily for electrical generation)
Source for fissionable materials (uranium)
Solar (sunlight for heat capture or electricity production-photovoltaics)
Geothermal (capture of earth’s heat or use of steam to produce electricity)
Wind (capture of kinetic energy)
Plants (production of biodiesel and alcohols)
Petroleum products (gasoline, fuel oil, jet fuel, kerosene, diesel, asphalt)
Shale oil (kerogen derived from oil shale)
Refined natural gas
Biomass conversions (anaerobic processes that produce methane; direct burning to produce heat or steam)
Coal conversion technologies (coal gasification and coal liquefaction)
Nuclear Fission (capturing the radionuclides from fissionable uranium to produce heat and then steam – electricity generation)
Electricity (generated from coal, oils, nuclear fission, photovoltaics, wind, hydropower, etc.)
Space and water heating (heat captured from burining chemical fuels, solar gain, biomass conversion, geothermal sources, electricity)
Biodiesel (oils generated from flax, corn, microbial transformation)
Fuel Cells (using hydrogen sources to generate electricity)
Industrial (factories, waste processing)
Commercial (service sector, business sales)
Residential (homes)
Transportation (auto, train, bus, shipping companies)
Tracking Energy Flows
Energy Flow Analysis
Tracking the conversions of energy in a process and accounting for entropy losses
Can use symbols to depict the utilization, storage, or losses of energy from a system
Accounting for all the steps in capturing primary energy sources, conversion to secondary fuels, and applications by end users
(more steps in process, more energy lost from the system)
Transformation of Energy in Energy Flow Diagrams
In energy flow diagrams, R (respiratory loss) represents the heat loss from a system (see textbook for examples of energy flow charts)
Aside from nuclear energy, major part of energy we use comes either from the sun directly or is energy that came from the sun
tens to hundreds of millions of years ago which is stored as chemical energy in fossil fuels.
Energy Usage Patterns (Production & Consumption)
Fossil Fuels
Petroleum, Coal, Natural Gas, Kerogen, Tar Sands, Peat
Renewable Energy Sources
Solar, Hydropower, Wind, Biomass
Nuclear Energy
Steam production for electrical generation
Industrial (coal, petroleum)
Commercial (natural gas, petroleum and electricity)
Residential (heating fuels, electricity)
Transportation (petroleum for gasoline, natural gas, electricity expanding)
End Users (comparison in different decades)
Energy for Services
Space Heating = 7.78 EJ* Water heating = 1.00 EJ
Refrigeration = 182 TWh*
Lighting = 246 TWh
Process Heat = 9.57 EJ (manufacturing)
Feedstocks = 7.68 EJ
EJ = exajoules (1,000,000,000,000,000,000 joules) = quadrillion BTUs = quad
TWh = terawatt-hours (1,000,000,000,000 watt-hours)
Historic trend of increased energy consumption
(rise of civilization, size of population; level of industrialization and economic growth
Looking for ideal energy source
It takes energy to get energy (entropy)
Tendency toward inefficiency
(e.g., 44 exajoules consumed in 1960; only 1/2 effectively used)
Disparities in Per Capita Energy Use
Developing Country (1-2 barrels of oil/ yr)
Europe/Japan (10-30 barrels of oil/ yr)
U.S. (40 barrels of oil/ yr)
Unequal Distribution of Supply
Geological deposits (limited production)
Inability to purchase fossil fuels/ electricity (economic deprivation)
Primary Energy - fuels mined from earth [crude oil, coal, uranium]
Delivered Energy - fuels available to users [gasoline, nuclear fuel, coal gas]
Useful Energy - conversions to form useful commodities [electricity, transportation, space heating]
U.S. Fuel Production (see charts in textbook and student presentations)
U.S. Fuel Consumption (see charts in textbook and student presentations)
Conversion Efficiency
Energy transformations reflect Laws of Thermodynamics
Energy can neither be created nor destroyed
Energy conversions can occur, but are not 100% efficient (Entropy)
More conversion stages --------> reduces usable energy; increases "quality" of energy
Petroleum, Natural Gas, Coal, Oil Shale (Kerogen), Tar Sands
Formed from organisms of the past
Carbon-based fuels (produce carbon dioxide, sulfur dioxide, and nitrogen oxides)
Petroleum products important, including feedstock chemicals
Hydropower (waterfalls, dams, tidal power, pumped water storage)
Solar power (passive solar design, active solar collectors, photovoltaics)
Geothermal applications (steam supply, steam generation, direct heating)
Marketing renewable technologies
(Soybeans)
Wind power (small or large-scale turbine use; expanding rapidly outside the U.S. -for example, China and Europe)
Conversion of carbon-based materials by aerobic or anaerobic processes to usable fuels or direct production of heat
Examples: Composting of sewage sludge or agricultural wastes; production of ethanol from plant materials; growth of algae for usable oils
Uranium fuel in reactor produces heat
Electrical generating plant based on steam production
Produces radioactive waste (includes plutonium, strontium, and iodine)
Reactors need extensive safety redundancy (high cost; difficult siting)
Electrical production can use any fuel that will heat water (change to steam)
Widely used in industrial, commercial and residential sectors
Steam turbine, electrical generator, transformer, grid distribution to users
Associated with chemical and thermal pollution; difficult to store; must account for transmission losses
Possible to produce electricity directly through fuel cells or by photovoltaics
Improved energy efficiency gains
Can be practiced across the socio-economic spectrum
Industrial/ Sector - pumps, motors, automatic controls, light trucks, JIT
Residential Sector - Insulation, improvements in appliances
Adoption of green building practices, especially good passive solar design of buildings for managing heat and light
Often most easily accomplished by changing manufacturing
(see www.energy.gov for details)
Greenhouse Gases (Carbon Dioxide, Methane, CFCs)
Stratospheric Ozone Depletion (CFCs, Nitrogen oxides)
Acid Deposition (Sulfur dioxide, Nitrogen oxides)
Air Toxics (Mercury, Carbon monoxide, Heavy Metals)
Carbon Sequestration Techniques
Coal Mine Runoff
Oil Spills
Acid Deposition
Oceanic Pollution
Radionuclides
Shipping wastes, oil spills
Drilling platforms
Land Runoff (refineries, transporation)
Destruction of wetlands and coastal shelf waters
Mining and drilling wastes
Fuel transformations (refineries, electrical production, biomass conversions)
Manufacture of feedstock chemicals
Fuel Cycle (mining, transport, storage, waste management, decommissioning)
Operational releases (low level radionuclides, emissions, runoff, equipment disposal)
Threat of accidents and consequent radioactive contamination
Consumption of carbon dioxide represents "the stored energy of a billion summers"
Equilibrium: Flow of carbon from atmosphere to forests and back to atmosphere (nature's "greenhouse effect")
30% more carbon in the atmosphere (by 2000) - human effects
Comparison: Venus (96% of atmosphere is carbon dioxide); Earth (about 1%)
Small change = great effect (increase of half a degree Celsius has already resulted in droughts, heat waves, and flooding in the U.S.
Need to have "development paths" for developing nations that skip a hundred years of fossil fuel burning
May be able to avoid "forcing" climate change to a "tipping point" beyond which we can't reverse the effects
Example 1: In China the growth of car ownership is 20% per year, but still low compared to the U.S.
China has 4 times the population of the U.S. (similar land mass)
What happens as the number of cars increase in China?
Example 2: In India 600 million people are still without electricity (India is growing faster than China)
What happens as the electrification is expanded? Especially if coal is the primary fuel used to produce electricity?
Farmer's Almanac predicting weather in the U.S. since 1792 (with 80% accuracy) - sell 4 million copies/year - do their climate models still work?
Canadian Climate Model - poses "what if" questions, model is tested by running it backwards (to "prove" the past
Based on the Canadian Climate Model - Agreement that (1) the rates of carbon dioxide addition will lead to warming; and
(2) the worst effects will be in the northern regions
ARCTIC - Snow surfaces are white and reflect light; water is dark and absorbs more light (warming further)
Positive feedback loop
Gulf Stream Conveyor Belt (warm water flows north and drops deep to ocean floor and flows back south again)
Britain - involving citizens in recording subtle changes in environmental patterns (leaf formation, bird migration, etc.)
South America - El Nino effects are heightened - increased rain, intense storms, increase in waterborne diseases like cholera
Increased coastal storms on Fire Island (1992)
Reduced vegetation in the Southwest (loss of the Pinon forests over millions of acres due to drought)
Global Food Production changed - variable climatic conditions may alter land productivity
In general - more drought than rain expected, drop in aquifers (already occurring), land loss (e.g., 100 yards/15 minutes in LA)
Huge smog areas in Southeast Asia (in 2002 a toxic cloud 3 miles high that lasted 5 months)
Increase in asthma cases (28% in males, 18% in females, from 1980 to 1990)
More carbon dioxide linked with increased pollen production, leading to increase in allergens
Many people locked in "climate denial"
Presently better consensus about existence of problems, but still lack of clarity about how to move forward
Some religious groups have begun to focusing on "creation care" (taking care of the earth)
Awareness that individuals CAN make a difference
Example: If we changed 5 light fixtures/U.S.family = 8 million cars = 5 power plants that could come off the grid
Need to calculate the "price of waiting" to change
Siting Difficulties
Effects of Radiation
Good fuel/output ratio
High heat/unit of fuel
Available sources of uranium in U.S.
Endorsement of the energy industry
Desire to cut back on fossil fuels and reduce carbon dioxide releases
Inherent dangers of exposure to radiation
Miners, power plant workers
Low-level releases into air and water
Possible accidents
Difficulties of siting facilities in the U.S.
Lengthy and costly siting procedures (10 years)
Need for safety redundancy
NIMBY attitudes
Evacuation plans are difficult to implement
Utilization of U-235 as a fissionable material
Small proportion of yellowcake ore
U-238 more abundant (about 99.3% of ore)
Both are radioactive, with long half-lives
4.5 billion years for U-238
0.7 billion years for U-235
In the U.S. most uranium deposits are found in sandstone (about 30% of the world�s deposits)
The tailings are weakly radioactive but must be carefully handled
Ore must be enriched to 3-4% U-235 by weight (compared to >90% for weapons)
Pellets of enriched uranium are fabricated into uranium oxide (UO2) fuel rods (packed in zircaloy tubing, called �cladding�)
Fuel rods are placed in the reactor core
Fission process takes place in a reactor
As fissions occur in the reactor, more reactions are stimulated, to reach �criticality�
Fuel rods are surrounded by a �moderator� such as water
Heat is produced, to make steam for electricity generation
Safety redundancy guarantees that no emissions of radioactivity would be able to occur during an accident (�hopefully�)
Reactor core is placed within a containment building
Cooling system removes heat (helps to avoid exceeding a �critical� temperature)
�Control rods� control the fission process
Light Water Reactors
Contain ordinary water as the moderator
Common reactors in the United States
Graphite Cooled Reactors (Russian type)
Breeder Reactors (LMFBRs)
Can be utilized for reprocessing spent fuel rods
No currently operating facilities in the U.S.
Can use U-238 as one of the fuels
Nuclear reactions must be controlled
Cannot allow reactor contents to overheat or exceed a controlled level of fissions
Could result in a runaway reaction
Reactors have coolants to prevent overheating
Steam generated via nuclear reactions must be condensed and returned to a waterway
Can lead to thermal pollution of a lake or bay
Spent fuel rods (SURF)
Very radioactive (after about 3 years of use)
Usually stored in water pools on reactor site
Could be �reprocessed� into uranium and plutonium (done in France, Russia, Japan)
High-level radioactive wastes (HLW)
Comes from reprocessing of the fuel rods
Generated from weapons production in U.S.
Transuranic Wastes (TRU)
Material with long half-life, alpha-particle emitting radioactive isotopes (100 nCi/g)
Primarily defense wastes
Mining or processing wastes
U-238 that could be used in breeder reactors
Mine tailings (contain uranium, radium and radon gas)
Low-level radioactive wastes (LLW)
Wastes not classified as SURF, HLW, or TRU
Weakly radioactive
Associated with medical and educational-research institutions, commercial, and defense facilities
Highly radioactive wastes covered by the Nuclear Waste Policy Act of 1982
U.S. national depository for nuclear wastes
Located near Las Vegas, Nevada
Underground complex (about 3 square miles in size) of interconnected tunnels
Located in dense volcanic rock 305 m beneath the mountain
Transport issues for truck and rail routes
Estimated 25-30 years of active life
Decommissioning is required after site becomes too radioactive to guarantee safety of workers and surrounding community
Most reactors presently operating in the U.S. are approaching their life expectancy
Mothballing the site, or total disassembly
Adds to the cost of nuclear-generated power
Storage of existing plants (guarded by the utility company for 50-100 years)
Dismantling would be safer at a later time because some radioactive materials would decay, but accidental leaks are possible
Entombment (permanently encasing the facility in concrete)
Would be intact for about 1,000 years
Decommissioning (dismantling of plant immediately after closure)
Workers would wear protective clothing
May possibly utilize robotics
Transport to a permanent storage site
Most responsible action to take
Need permanent storage sites
Shippingport (Pennsylvania) � first nuclear power plant in the U.S.
Dismantled in 1989; moved to Hanford Nuclear Reservation in Washington state
Many nuclear plants ready for retirement
87 nuclear plants permanently retired � 1999
93 plants over 25 or more years old in 1999
Costly process ($370 million for Yankee Rowe)
LOCA (Loss of Coolant Accident)
Can permit the reactor to overheat
May lead to other consequences; other backup systems may fail
Example: Three Mile Island, Harrisburg, PA (March 28, 1979)
Partial meltdown occurred (50%), but held within the containment building
Core Meltdowns
Caused by excessive heat whereby the contents of the reactor can melt down
Can lead to groundwater contamination and offsite effects
Explosion and Fire
Can release large amounts of radioactivity
Example: Chernobyl, Ukraine (April 26, 1986)
Radiation spread quickly into Belarus and throughout northern Europe (Sweden, Norway, France, Switzerland)
116,000 people evacuated (within a 30-km radius); eventually 170,000 people had to abandon their homes
Damaged reactor was encased in concrete (sarcophagus)
Long-term health and economic effects
Reactor design was flawed (RBMK)
Graphite moderator (reacts to dramatic temperature changes
Reactor was not encased in a containment building
Reactor was extremely unstable at low power
Human error contributed to accident
Radiation is presently escaping from the site
Somatic Effects
Can include burns, organ damage, reduced immunity, or even be fatal
Genetic Effects
Alters sperm or egg cells, thereby creating mutations that can be passed on to offspring
Acute vs. Chronic Exposure
Varies with dosage and duration
Curie � 3.7 million disintegrations/second
Picocurie � 1/trillionth (10-12) curie (pCi)
Roentgen � basic unit of radiation energy
Measures of Radiation Exposure
Rads (amount of radiation exposure)
Rems (human exposure equivalency)
(1 rem = 100 ergs of absorbed radiation/gram of matter, multiplied by a factor for each type of radiation, e.g. 20 for alpha radiation)
Background radiation is about 100 mrem
European term: Sieverts
(1 sievert=100 rads)
Radon-222 is a byproduct of the breakdown of uranium
Flux of radon everywhere, but more concentrated in some areas (e.g., with granite rock formations)
Half-life of 4 days
Decays into radioactive lead, polonium, bismuth (radon daughters)
Radon daughters are extremely carcinogenic
Particularly a problem in �tight� houses that are located over high-uranium rocks
Common situation in New England and in many Western states
5,000 to 30,000 lung cancer deaths/year are due to radon daughters formed indoors from radon-222
Houses need to be tested for radon
EPA programs for this purpose
4 pCi/L (4 picocuries per liter of air) is the standard used by the EPA
Equivalent to smoking 4 cigarettes/day
Outside air is usually 0.8 to 1.5 pCi/l and indoor air averages 1.0 to 2.0 pCi/l
Fusion process also takes place in a reactor
Called a tokamak (Russian for �fusion reactor�)
Requires excessively high temperatures and pressures for reactions to occur
Based on fusing of different atoms, with a heat release
Not yet commercially available ($10 billion already invested by U.S.)
Strong interest in future applications
Fusion process could produce considerable amounts of energy
Isotopes of hydrogen are fuel (e.g., nuclei of deuterium and tritium unite to form helium)
Deuterium, called �heavy hydrogen� is found in water and easy to separate
Tritium is radioactive and does not occur in nature (formed from lithium found in seawater)
Illustrations of Reactors
U.S. Department of Energy Web Site
Overview of a Nuclear Facility
Student Team Web Site
(see www.energy.gov for details)
Greenhouse Gases (Carbon Dioxide, Methane, CFCs)
Stratospheric Ozone Depletion (CFCs, Nitrogen oxides)
Acid Deposition (Sulfur dioxide, Nitrogen oxides)
Air Toxics (Mercury, Carbon monoxide, Heavy Metals)
Carbon Sequestration Techniques
Coal Mine Runoff
Oil Spills
Acid Deposition
Oceanic Pollution
Radionuclides
Shipping wastes, oil spills
Drilling platforms
Land Runoff (refineries, transporation)
Destruction of wetlands and coastal shelf waters
Mining and drilling wastes
Fuel transformations (refineries, electrical production, biomass conversions)
Manufacture of feedstock chemicals
Fuel Cycle (mining, transport, storage, waste management, decommissioning)
Operational releases (low level radionuclides, emissions, runoff, equipment disposal)
Threat of accidents and consequent radioactive contamination
http://www.ecomall.com/greenshopping/cleanair.htm
https://ocean.si.edu/conservation/pollution/gulf-oil-spill
https://www.ran.org/issue/jpmc/
I. Set up an Energy Management Team (7-9 people)
II. Establish energy use patterns
III. Conduct a walk-through of the entire facility
IV. Determine energy consumption
Use all cost data
Factor in team observations during earlier stages
V. Identify ECOs (Energy Conservation Opportunities)
VI. Prioritize ECOs, set budgets and action strategy
VII. Implementation phase
VIII. Follow-up Evaluation (assess success of ECOs)