AVG = 74.4%

Tuesday Nov 11Chpt. 10Electricity Basics Thursday Nov 13Chpt. 11Electromagnetism Tuesday Nov 18 Electrical GenerationHW7 Thursday Nov 20Chpt. 12Solar electricity Tuesday Nov 25 Kinetic sources Thursday Nov 27 Thanksgiving Tuesday Dec. 2????The Future Thursday Dec. 4????The Future HW8( replaces Art. sum 3) Tuesday Dec 9????The Future Thursday Dec 11????The FutureTerm paper Tuesday, Dec FINAL EXAM7:15 PM Revisions to course Schedule

(Woods Hole Research Center) Sediments and sedimentary Rocks could account for another 6x10 7 Petagrams! (

H&K Fig. 9.6: Feedback (positive and Negative) “Butterfly effect” in complex systems

Green House gases Contributions to green house effect depend on IR absorption, concentration and lifetime in the atmosphere. GASSourcesGW P Lifetime (yr) 2003 conc. ppm CO2 (5500 MT/y) Burning organics/ deforestration CH4 (600 MT/y) Rice fields, landfills, animals NOx (16 MT/y) Fetilizer/defor- estration, vehicles CFC’s (1MT/y) Aerosol sprays, refrigerators, ACs’ NF3 (<2-3kT/y) Plasma cleaning FP displays etc GWP: “Global Warming Potential”: the ability of the gas to trap IR light (heat).

Carbon Sequestration (“Clean coal” as of ~ 2000) Research and Creative Activity, Oct 2008, IU OVPR publication Note that “clean coal” is a term that has been around for a long time, but it has only recently morphed into this incarnation. Originally it referred simply to using low-sulfur coal, then to including emission control measures, and finally to include limits on CO 2 emissions. It’s true meaning in the mind of the user is therefore to be taken with some appropriate degree of skepticism!

Kyoto Protocol ( ) Green: Signed and ratified Yellow: Signed with ratification pending Red: Signed and declined to ratify Grey: No position Built on Rio Summit of 1992, been “in force” since Oct Goal is to reduce developed nations CO2 emissions by 5% from 1990 levels

10 ppm ozone at ~ 50 km compared to 40 ppb ozone in the troposphere!

Ozone levels at Halley Bay station (Antarctica)

TOMS Satellite movie ( Total Ozone Mapping Spectrometer )

TOMS Satellite movie ( Total Ozone Mapping Spectrometer ) Sept. 2006

Montreal Protocol (1987-9) An agreement to limit the emission (and eventually eliminate the use) of CFC’s that contribute to Ozone depletion. In force as of 1989, modified several times (most recently Beijing 1999). Has been hailed as one of the UN’s most successful international agreements.

Thermal Pollution Remember, all energy production eventually leads to thermal energy being dumped into the environment. To carry the waste heat away from a 1000MWe power plant requires about 10 4 gallons/second (for an 8K temp. rise). In an increasing number of (local) applications, some of this waste heat is used to heat local buildings (“co- generation”)

U. Cincy Cogeneration Plants Two generating stations: 47MW combined. Annually produces: 245M kWh Heat to 9Msq.ft of bldg space Various fuel options can be used.

Impact of Thermal Pollution Reduced oxygen content in lakes/rivers/ponds the heat is released to. Changes in reproduction, growth and behaviour throughout the food chain; e.g. algae plumes Chemical reaction rates increase. Changes in local temperature gradients (especially vertical gradients) can upset the natural exchange of nutrients between surface and deep water

Thermal Pollution: Local water sources

Cooling towers

Term paper (see website) ASSIGNMENT: You are to research some technology related to energy (production, conservation, mitigation of side effects, etc.) that has been implemented recently or has been proposed for use at some point in the future. The paper should describe the technology in sufficient detail for an intelligent but uninformed reader can understand its function, and it should state (and support) your own argument for why this technology should or should not be implemented in the market place. See the link on the web site for more details.

Possible topics Fuel cells Wind farms. Passive/active solar heating Geothermal climate control High-efficiency appliances Next generation nuclear plants. Solar Cells, what promise exists in recent materials advances? Personal transportation options. Alternative organic fuels Options for storing radioactive waste from power plants. Nuclear Fusion Methane clathrate Control measures for any pollutant of your choice (including carbon). Advanced oil recovery methods Biomass fuels Cogeneration technologies Hydrogen economy (this has lots of possible subtopics, storage, generation, use, hazards etc.) Future automobile design (again lots of subtopics exist) The electrical power grid Real time pricing of electricity Others of your own choice.

Basics of electricity There is a force other than gravity that acts “at a distance” (and is stronger). This force can be attractive or repulsive “Static Electricity” comes in two flavours; we call these positive and negative (like charges repel, unlike charges attract). At least some of the charges in metals are very mobile. The force is stronger if charges are closer. We can define a potential energy associated with the relative location of charges (this is a conservative force).

Basics of electricity (cont.) The basics on the previous slide form the basis for all of our electrical technology! We measure charge in Coulombs (6.24x10 18 elementary charges) In electrical circuits, you have an “electromotive force” that provides the “push” (V: VOLTAGE, measured in VOLTS, a potential energy difference per unit charge 1 V = 1J/1 Coulomb) DEMO. Moving charges carry the energy (I: current, measured in AMPS 1 A =1Coul/sec). Power = I*V (1 watt = 1volt*1 Amp) The ratio of voltage to current is called the resistance of the circuit –OHM’s Law: V=IR (R measured in OHMS,  )

Resistance Electrical resistance is much like thermal resistance, it depends on the length and cross section of the wire, and on the material the wire is made of. R =  l/A –  : resistivity (e.g. Cu 1.69x10 -8  m; Al 2.75x10 -8  m) –l length of the wire –A cross-sectional area of the wire Wires designed to carry a lot of current must have a large cross sectional area.

Ohm’s Law The ratio of voltage to current in a circuit (or circuit element) is equal to the resistance of that circuit (or element) R = V / I V = I R I = V/R R is measured in OHMS (  ) 1  = 1V/1A.

Series and Parallel Circuits Series circuit: Current is the same in all elements (voltages add) Parallel circuit: Voltage is the same in all elements (Currents add)

Examples Consider a 1200W North American toaster. What current does it draw? If it is used to toast two slices of bread in 1 minute, how much does toasting each slice cost (take $0.08/kWh for the cost of electricity). A 50  resistor is connected across a voltage of 120V. What is the power dissipated in the resistor?

Batteries All batteries have the same basic principle, but the chemical reactions and The materials used for the electrodes and electrolytes) differ. This gives Different voltages, internal resistances, masses, operating temps, etc. H&K p 327

Batteries: Energy Density (as of Jan. 2004, note on this scale, gasoline is Wh/kg and 9500 Wh/l) Compare these numbers to table 10.1 in the text.

North American Power Plants

US Electrical power Look at the text, which Shows an interesting Distinction between Utility producers and Non-utility producers In terms of this mix. (p 319)

US Electrical Power Generation

U. Cincy Cogeneration Plants Two generating stations: 47MW combined. Annually produces: 245M kWh Heat to 9Msq.ft of bldg space Various fuel options can be used.

US Electrical power