Post on 03-Jan-2016
Energy provides the power to do work Work is defined as force exerted over
distance. Power is the rate of flow of energy or the
rate at which work is accomplished. Another way to measure energy is to
measure force and work.
A newton describes the force needed to accelerate 1 kilogram by 1 meter per second.
A joule is the amount of work accomplished when a force of 1 newton is performed over 1 meter or 1 ampere per second travels through 1 ohm (a unit of electricity)
Btu (British thermal unit) - amount of energy required to raise the temperature of 1 lb of water by 1 ºF.
cal (calorie) - the amount of energy required to raise the temperature of 1 g of water by 1 ºC. Commonly, kilocalorie (kcal) is used.
1 Btu = 252 cal = 0.252 kcal1 Btu = 1055 J (joule) = 1.055 kJ1 cal = 4.184 J
Two other units that are often seen are the horsepower and the watt. These are not units of energy, but are units of power.
1 watt (W) = 3.412 Btu / hour1 horsepower (hp) = 746 W
Watt-hour - Another unit of energy used only to describe electrical energy. Usually we use kilowatt-hour (kW-h) since it is larger.
1st Law of Thermodynamics: energy cannot be created or destroyed – only rearranged into different physical & chemical forms.
2nd Law of Thermodynamics: When energy is changed from one form to another, some of the useful energy is always degraded to lower-quality less useful energy.
Energy concerns Amount of energy needed during energy refining
and production Processing accounts for nearly half of all energy
lost during conversion to more usable forms, transportation, or use
When coal is used to produce electricity, nearly 65% of the original energy is lost during thermal conversion at the power plant.
Another 10% is lost in electrical transmission and voltage changes for household use
Fossil fuel refining 75% of oil’s original energy is lost during distillation
into gasoline and other fuels, transportation to market, storage and engine combustion
Natural gas Much less waste since it needs little refining Transported through pipelines Burned with 75% to 95% efficiency Contains more hydrogen to carbon ratio, less CO2
produced
Brief history of energy*1700-1800 Fire wood*1900-1920 Coal*1950- now crude oil
“production of crude oil” = with drawing it from reserves
OPEC (pg 314) organization of petroleum exporting countries (Mid-east countries mainly)
Solar 3 – 4% Oil 33% Biomass 11% Nuclear 6% Hydroelectric 3 – 4%
Decrease in crude oil production
Increase in crude oil consumption
So … the price went up
Jan. 1969 Santa Barbara, Ca: oil well explosion (blowout); 3 million gallons of crude oil poured into the Santa Barbara Channel
March 1989: Exxon Valdez (transportation); 53 million gallons poured Prince William Sound
April 2010 Gulf of Mexico: BP Deepwater Horizon oil well blowout; 11 workers injured; 206 million gallons
2005 Texas: explosion at a BP oil refinery; 15 workers died
April 2010 West Virginia: explosion in coal mine; killed 29 miners
Fossil fuels – derived from biological materials that are fossilized Coal, oil and natural gas Fossil fuels are burned and the heat energy is
harnessed from their combustion Nuclear fuels – derived from radioactive
materials that give off energy Energy is harvested by transferring heat
In 1956, M. King Hubbert predicted that U.S. oil production would peak in the early 1970's. In 1971 his prediction came true.
1969, he predicted that 80% of the world’s total oil supply would be used up in roughly 60 years
There are long-term solutions to our future energy problems: conservation fossil fuels renewable energy sources
Large-scale implementation of these solutions requires more than five years and the industrialized nations have done little to address the short-term problem.
Changes in U.S. Energy Use
Energy resources removed from the earth’s crust include: oil, natural gas, coal, and uranium
WHAT DOES IT LOOK LIKE? ROCK! Oil is found inside pores of rock in droplet form
WHERE IS IT FOUND? Mostly along tectonic belts (plate boundaries)
WHAT TYPE OF ROCKS? Mostly porous rocks (sandstone, limestone) are reservoir rocks. Hydrocarbons are pushed to the surface and capped.
HOW DOES IT FORM? Buried organic material, heat & pressure
CRUDE OIL – fossil fuel produced by decomposition of deeply buried dead organic matter
MADE OF? Mostly hydrocarbons, some sulfur, oxygen and nitrogen too!
METHODS OF PROCESSING: Primary Recovery Secondary Recovery (35%) P &
S Enhanced or Tertiary Recovery
(10-25%)TERTIARY RECOVERY PROCESS
Fractional distillation – separates the parts by pulling them off at various boiling points
Asphalt, DDT, polystyrene, nylon
Pros Cons
-Cheap -Limited US supply
-Transportation -Pollution (air, water)
-High net energy yield -Land Disturbance
Low Prices encourage waste – infrastructure inhibits change or improvements in energy efficiency
Distillation process for oil accounts for 8% of US energy consumption!! MUST USE ENERGY TO
MAKE ENERGY!!
OIL SHALE Fine grained rock
containing solid, waxy mixture of hydrocarbons (kerogen)
Known as a synfuel (synthetic of fossil fuels – oil from kerogen)
TAR SAND Mixture of clay,
sand, water & bitumen
Often found in sedimentary rock formations
Most reserves are found in Alberta, Canada
•Resources and ReservesTotal amount of oil in the world is estimated at 4 trillion barrels. (Half is thought to be ultimately recoverable)
-In 1999, proven reserves were estimated at 1 trillion barrels.
As oil becomes depleted and prices rise, it will likely become more economical to find and bring other deposits to market.
Mostly methane (CH4), trace amounts of ethane, propane, butane and hydrogen sulfide
Form from breakdown of hydrocarbons (petroleum) in places of intense heat & pressure
Found above most reservoir rock of crude oil
Butane & propane are removed and liquefied natural gas and stored as pressurized gas
US = 2-3% US 60-70 yr. Supply Russia & “stans” =
40% Provides ¼ of all
the energy used in the United States
World Reserves ~ 125 yrs
Very Plentiful – if it can be recovered!
easy to transport (pipelines)
easier to process than coal or oil
High energy yield!! LOW POLLUTION
FACTOR** Burns cleanly & almost
entirely Extraction does less
damage to the environment (pipes verses mining of rock)
• H2S & SO2 are produced
• Must be converted to LNG before it can be shipped (Liquid N.G)
• Conversion of LNG reduces energy yield and is expensive and dangerous
• Could leak in the atmosphere and methane = more damaging greenhouse gas than CO2
US, Russia & China contain 80% of the proven reserve
Precursor to coal
Young coal; sometimes called brown coal; lowest carbon content
Lower carbon & sulfur content than other types
Highest sulfur content & most plentiful
Highest carbon content; most rare
TYPICAL COAL BURNING POWER PLANTSTYPICAL COAL BURNING POWER PLANTS
High CO2 emissions (greenhouse gas)
Other emission: SO2
(acid rain); NOx; & Mercury
Human health impact – respiratory diseases
Large disruption to land
Acid Rain
Global Climate Change
ENVIRONMENTAL IMPACTSENVIRONMENTAL IMPACTS
Coal Supplies 50% of our electrical needs in the United
States
China largest global consumer of coal reserves
High land impact
Increased Surface Mining
High CO2 emissions
Higher cost
Lower net yield
COAL GASIFICATION
Disadvantages
Advantages Large supply
Vehicle Fuel
Produces synthetic natural gas by coal liquefaction
1)Removes most of the sulfur dioxide
2)Reduces emissions of NOx
3)Burns coal more efficiently and cheaply than conventional methods
Fluidized-Bed Coal Combustion
Cleaning - Chemical/Physical cleaning of coal prior to combustion
Scrubbing - injection of limestone into gases, reaction of carbonate with sulfur dioxide produces calcium sulfate (sludge)
CLEANING UP COAL!
Disturbed land; mining accidents;health hazards; mine wastedumping; oil spills and blowouts;noise; scarring; heat; subsidence
Solid waste; radioactive waste;air, water, & soil pollution;
noise; safety & healthhazards; heat
Noise; uglinessthermal water pollution;
pollution of air, water, and soil;solid and radioactive wastes;
safety and health hazards; heat
Use
transportation or transmissionto individual user,
eventual use, and discarding
Mining
Exploration; Extraction
Processing
Transportation; purification,
manufacturing
ENVIRONMENTAL IMPACT TO MINING PRACTICES & USE
Percolation togroundwater
Leaching of toxic metalsand other compounds
from mine spoil
Acid drainage fromreaction of mineralor ore with water Spoil banks
Runoff ofsediment
Surface MineSubsurfaceMine Opening
Leaching may carryacids into soil and
groundwater supplies
ENVIRONMENTAL DAMAGE FROM MINING PRACTICES
IMPACT:
1962: Pop. Of 1,100 – 2,000
545 Families & Businesses
1996: Pop. Of 46
20 Families - NO businesses
Megawatt
Radioactive
Waste
Atomic
Bomb
Nuclear
Weapons
Number of power plants today: 439 worldwide
Nuclear power generates about 15% of the world’s electricity (about 10% of U.S.)
ADVANTAGES
Large Supply
Low Environmental Impact
Emits only 1/6 of CO2 as coal
Moderate land and water disruption (without accidents)
DISADVANTAGES
High Cost – even with Govt. subsidies
Low net energy yield (facilities $$)
Major Accidents are HIGH environmental cost
Thermal Pollution
Waste Solutions??
Encourages Technology for Weapons Use
Electricity
Very High Temps (2,500°C)
Nuclear Fusion/Fission
Concentrated Sunlight
High Velocity Wind
Fossil Fuels (Coal, Oil, NG)
Hydrogen Gas
Food (chemical energy)
Normal Sunlight
High Velocity Water Flow
Moderate Temp
(100-1000°C)
VERY HIGH
HIGH
Moderate
Industrial Processes
Motors, Lights and other
Electrical Devices
Mechanical Motion
Producing Electricity
Producing Steam
Cooking, Electricity
Natural Radioactive Decay – unstable isotopes spontaneously emit fast-moving particles (radioactive isotopes/radioisotopes)
Radioactive isotopes emit ionizing radiation (biologically damaging) in the forms of 1) alpha 2) beta and the most common being 3) gamma rays
Radioactive isotopes spontaneously decay at a characteristic rate into a different isotope. This
rate of decay is expressed in terms of half-life. (The time needed for one-half of the nuclei in a
radioisotope to decay)
Typically radioactive isotopes must be stored for 10 half-lives before it decays to what is considered a “safe” level
Plutonium-239 used in nuclear reactors & weapons must be stored safely for 240,000 years!! What is its half-life??
Radioactive isotopes continue to decay producing a series of different radioisotopes until a non-
radioactive isotope form is produced.
The time needed for one-half of the nuclei in a radioisotope to decay and emit their radiation to form a different isotope
Half-time emitted Uranium 235 710 million yrs alpha, gammaPlutonium 239 24.000 yrs alpha, gamma
During operation, nuclear power plants produce radioactive wastes, including some that remain dangerous for tens of thousands of years
Half-Life
There are three main types of ionizing radiation. They may be found in sources of man-made radiation as well as natural radiation sources. They are called: 1) alpha, 2) beta, & 3) gamma
Alpha particles (protons & neutrons) can be shielded by a sheet of paper or by human skin. However, if particles that emit alpha particles are inhaled, ingested, or enter your body through a cut in your skin, they can be very harmful.
Some beta particles (electrons) can be stopped by human skin, but some need a thicker shield (like wood) to stop them. Just like alpha particles, beta particles can also cause serious damage to your health if they enter your body.
Examples of some alpha emitters: radium, radon, uranium, thorium.
Examples of some pure beta emitters: strontium-90, carbon-14, tritium, and sulfur-35.
Gamma rays are the most penetrating of the three types of radiation listed here. Gamma rays usually accompany beta, and some alpha rays but are not associated with any atomic particle. Gamma rays will penetrate paper, skin, wood, and other substances. To protect yourself from gamma rays, you need a shield at least as thick as a concrete wall. This type of radiation causes severe damage to your internal organs.
Radioactive materials (some natural and others made by man in things like nuclear power plants) can emit gamma-rays. But the biggest gamma-ray generator of all is the Universe! It makes gamma radiation in all kinds of ways.
We measure radiation dose in units called rem (or rads). Scientists estimate that the average person in the United States receives a dose of about 360 millirem of radiation
per year. Legal limit of exposure is 5000 millirems.
Uranium -235 and Plutonium-239 are naturally fissionable isotopes
Nuclear Fission is used to produce electricity under controlled nuclear reactions in reactors. Fission produces intense heat and in turn creates high pressured steam to drive turbines for energy production.
Fusion requires energetic collisions of very light elements, usually hydrogen isotopes, resulting in a nuclear reaction that leads to more stable helium nuclei and other byproducts. A net loss of mass results, yielding free energy as given by Einstein's famous equation.Used in WWII to produce weapons (uncontrolled nuclear fusion).
Controlled nuclear fusion to produce electricity is VERY expensive & not efficient yet.
Ectotherms Infrared Image Endotherms Infrared Image
Yellowstone Geyser – Old Faithful Pencil after being sharpened
Ionizing vs. Non-Ionizing Radiation
Ionizing Radiation has been proven to cause cancer (1% of cancers) & genetic defects (~5%). Non-ionizing radiation is hypothesized to cause cancer, birth defects, etc. at high doses.
• Genetic damages: from mutations that alter genes
• Genetic defects can become apparent in the next generation
• Somatic damages: to tissue, such as burns, miscarriages and cancers
Effects of Radiation
Temporary Blood Count Change (Whole Body or Torso)
25000 mrem
Permanent Sterilization in Men (Gonads) 100000 mrem
Permanent Sterilization in Women (Gonads) 250000 mrem
Skin Erythema (Burn) 300000 mrem
Cataract Formation 600000 mrem
Primary environmental problem in disposal of radioactive waste
Low-level radiation (Gives of low amount of radiation) Sources: nuclear power plants, hospitals &
universities 1940 – 1970 most was dumped into the ocean Today it is incinerated, compacted and buried
in landfills
High-level radiation (Gives of large amount of radiation) Fuel rods from nuclear power plants Half-time of Plutonium 239 is 24,000 years No agreement about a safe method of storage Stored at reactor site
Possible plan for the US Bury it into Yucca Mountain in desert of Nevada Cost of over $ 50 billion 160 miles from Las Vegas Transportation across the country via train &
truck Some plants are using dry fuel storage
Fuel is sealed in a metal container surrounded by metal or concrete and placed on a concrete pad
Designed to resist floods, tornadoes, projectiles, temperature extremes, and other unusual scenarios
Yucca Mountain
www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt
238U is the most plentiful isotope of Uranium
Non-fissionable - useless as fuel Reactors can be designed to
convert 238U into a fissionable isotope of plutonium, 239Pu
During the operation of a nuclear reactor the uranium runs out
Accumulating fission products hinder the proper function of a nuclear reactor
Fuel needs to be (partly) renewed every year
Spent nuclear fuel contains many newly formed plutonium atoms
Miss out on the opportunity to split
Plutonium in nuclear waste can be separated from fission products and uranium
Cleaned Plutonium can be used in a different Nuclear Reactor
Concerns about the safety, cost, and liability have slowed the growth of the nuclear power industry
Nuclear Regulatory Commission (NRC) is the US governmental Agency that regulates nuclear power plants
Accidents at Chernobyl and Three Mile Island showed that a partial or complete meltdown is possible
Nuclear plants must be decommissioned after 15-40 years
New reactor designs are still proposed Experimental breeder nuclear fission reactors
have proven too costly to build and operate Attempts to produce electricity by nuclear
fusion have been unsuccessful
Some countries (France, Japan) investing increasingly
U.S. currently ~7% of energy nuclear 40% of 105 commercial nuclear power
expected to be retired by 2015 and all by 2030
North Korea is getting new plants from the US France 78% energy nuclear Government funds and incentives to build
new plants Southern Company building at Plant Vogtle in
Georgia
Hubbert
Three Mile Island Chernobyl Arctic National Wildlife Refuge Area &
drilling of oil Texaco & the Ecuadorian Amazon