Chem 370 / ENTS 369 - Spring 2003

Daily Assignments (listed here in reverse chronological order)

For Wednesday, June 4:

• Read Chapter 7 and the Epilogue in the Consumer's Guide to Effective Environemental Choices
• Let me know by email when you plan to take your exam, if you haven't already taken it

For Monday, June 2:

• Read Chapters 5 and 6 in the Consumer's Guide to Effective Environemental Choices
• Think of things you would be interested in asking Rich Strong and/or Alyssa Thomas about

For Friday, May 30:

• Read Chapter 4 in the Consumer's Guide to Effective Environemental Choices
• Consider taking your exam this weekend! (If you would like to do so, let me know by email.)

For Wednesday, May 28:

• Review Chapter 3 in the Consumer's Guide to Effective Environemental Choices
• Look over your assignments and be sure you understand any mistakes (or lucky guesses!)

For Monday, May 26:

• Review Chapters 1 and 2 in the Consumer's Guide to Effective Environemental Choices
• Complete the wind analysis assignment described below, for Friday, May 23.
• If you don't yet feel confident with the results of the turbine economics calculations from Wednesday, give that another try.

For Friday, May 23:

• Finish reading the Guided Tour on Wind Energy from the Danish Wind Industry Association
• Continue your wind energy case study by analyzing some actual wind data from anemometer towers erected in Nerstrand and Northfield:
  • We want to get some idea of the diurnal (daily) and seasonal (monthly) variations in wind typical here in the Carleton College neighborhood
  • Wind data for Northfield (less extensive, more timely and actually measured where we are planning to install our turbine) and Nerstrand (more extensive, includes 70 m data) is available from the Plains Organization for Wind Energy Resources (POWER) through this link.
  • The Carleton College Weather Database provides weather data, including anemometer data from on top of Mudd, probably at the standard 10 m height
  • This is real data, so you will find that
  • There's a lot more data available than you actually need
  • Not all of the data is good; sometimes the devices break down or don't log their output properly
  • The data may not be perfect for the task at hand, but unless you want to erect an 80m anemometer tower yourself, and wait a few years for it to collect data, it'll have to do
  • Based on the data available from these sites, and what you learned in the Guided Tour, try to estimate the following for next Monday:
  • The average wind speed for each month at 80m in the Northfield location
  • The "typical" daily wind pattern in the Northfield location, if such a thing exists
  • The approximate average air density (by way of the temperature) for each month in the Northfield area at the time the wind blows hardest!

For Wednesday, May 21:

• Read the discussion of payback time in section 11 (§11.7), and all of section 12 in the Guided Tour on Wind Energy from the Danish Wind Industry Association
• Continue your wind energy case study using the Guided Tour's Wind Turbine Power Calculator, clicking the link to the Wind Energy Economics Calculator therein so that both calculators are open and the results of the former automatically feed into the latter. We are going to do an analysis of turbine options for the location planned for Carleton's wind turbine.
  • We are making a relative comparison here, so some of the entries won't make a huge difference. Use the values I list here for now.
  • Assume an altitude of 280 m above sea level and a temperature of 10ºC (let the calculator determine the pressure)
  • Anemometer studies indicate an average windspeed of 6.63 m/s with a Weibull shape parameter of 2.15 at 50 meters
  • Choose what you think is a reasonable roughness class or length based on the data in this table and the fact the proposed site is on farmland
  • To make the calculator allow you to use an 80 m hub height, start with the Vestas V80
  • To make the calcuator allow you to use a 72 m hub height, start with the NEG 900
  • Technical data on the three turbines under consideration was handed out in class today, including their power curves. Some of them might be standard options in the menus, but the NM82 certainly won't be (it is brand new). Where applicable, go ahead and use the 1.21 kg/m^3 power curve data, rather than interpolating
  • Here's some more general data extracted from quotes for the three different NEG turbines being considered:
  • All of them have a 20 year design lifetime
  • NM82/IEC III: 82 m rotor diameter, 80 m hub height, 1650 kW; $1,320,000 + $95,000 freight (count freight as an installation cost)
  • NM72/1500: 72 m rotor diameter, 80 m hub height, 1500 kW; $1,250,000 + $ 75,000 freight (count freight as an installation cost)
  • 2 x NM54/900: 2 turbines, 54 m rotor diameter, 72 m hub height, 900 kW each; $1,310,000 + $100,000 freight for both (count freight as an installation cost)
  • Today's handout also included estimated total installation costs for a one-turbine setup. Correct for the need for two turbines using the map and by assuming:
  • Underground cabling costs $8 per foot
  • Roads appropriate to the tower constuction and assembly task cost $4 per foot
  • Foundations are required for each tower, and their price (including labor) does not scale at all with the size of the turbine
  • Erection labor scales with the number of turbines, viz. $10000 per turbine
  • Other erection costs (like the cranes) are fixed
  • FAA lights are needed for each turbine, and they cost $5000 per tower
  • All other costs are fixed, independent of the number of turbines
  • We'll get 3.3 cents per kW-hr from Xcel
  • Use 1.5% of turbine price as an estimate of annual maintenance costs
  • The real rate of interest is presently about nil, but over 20 years it will probably go up, so let's assume 5%
  • Don't freak if the real cost exceeds the real price; you'll see why when you read the case study
  • Calculate the electricity cost per kW-hr for each turbine, and print out and bring your results to class where we will compare them and make sure everyone's on the same page (I had trouble printing from Mozilla; if that happens to you, just bring your calculated capacity factor, real return, cost per kW-hr, and installation cost values.)

For Monday, May 19:

• Read sections eight through ten (8-10) in the Guided Tour on Wind Energy from the Danish Wind Industry Association
• Pick a country you are interested in and read up on its energy usage in the DOE Energy Information Administration's Country Analysis Briefs
• Compare that info with what the CIA thinks is the case in the "Economy" section of their World Factbook
  (Note that not every country will appear in both [either?] of these publications!)
• Continue your wind energy case study by roughing out parameters that will be important to the "local wind" option:
  • Set up a cell in which to store the total initial cost of the system
  • Put in another for the monthly maintenance costs
  • Put in a cell that stores how much energy is produced by the turbine every month
  • Calculate the difference between supply and demand each month (assume it is flat, for now)
  • Prepare a cumulative monthly cost table for the electricity, like the one from last time
  • Combine this stuff to calculate how much money you would have left in your initial investment, if you drew it down to pay the electricity bills each month, while it accrued interest on the balance that hadn't been spent. How long could you supply electricity with this modified approach? (I'm not asking for a number yet, just a spreadsheet to calculate it.)

For Friday, May 16:

• Read the sixth and seventh sections (6-7) of the Guided Tour on Wind Energy from the Danish Wind Industry Association
• Read this Christian Science Montor Article on Wind Power
• Continue your wind energy case study by preparing a calculator for determining the cost of supplying electricity:
  • Put the number of kW-hr needed per month in one cell (assume this is time-independent, for now)
  • Put the effective average kW-hr price in another cell (again, we'll neglect seasonal cost variations for now)
  • Put the effective tax rate in another cell
  • Calculate the total monthly cost of the electricty based on these inputs
  • Prepare a cumulative monthly cost table
  • Modify your interest calculation from last time to produce a similar monthly cost table
  • Combine these two ideas to calculate how much money you would have left in your initial investment, if you drew it down to pay the electricity bills each month, while it accrued interest on the balance that hadn't been spent. How long could you supply electricity with this approach?

For Wednesday, May 14:

• Read the fourth and fifth sections (4-5) of the Guided Tour on Wind Energy from the Danish Wind Industry Association
• Compare the two fuel source pie charts on back of today's handout, the one on p. 64 of the reading packet, (all for MN) and for Xcel more generally on p.7 of their corporate environmental report. Why the big differences?
• Start your wind energy case study by setting up an Excel spreadsheet that can calculate the return on an investment over time:
  • Put your initial investment in one cell
  • Put the (simple) interest rate in another cell
  • Put the term in yet another cell
  • Calculate your total return based on those three entries and the other options required for the FV function. (Note: you're paying nothing new in!)
  • Note: interest payments are always paid out at the end of each payment term (which is the default for FV)
  • Figure out how much you would have after five years, having invested $2 million at a yearly dividend rate of 2.95%, compounded monthly.
  • Make sure the answer you get is $2,317,447. I had to fight with it a while myself. It shouldn't be hard, but Excel's a miracle worker.
    
• This spreadsheet will grow and expand over time, so make it neat and understandable. Use separate sheets on the same workbook to separate distinct ideas and to group related calculations. Please use only one workbook file.

For Monday, May 12:

• Read the first three sections (1-3) of the Guided Tour on Wind Energy from the Danish Wind Industry Association
• Look at the US and Minnesota wind maps

For Friday, May 9:

• Read about How a CCD device is manufactured
• Look over Czochralski Method Diagram and Pictures from MPI-FKF Stuttgart
• Read handouts on Foveon polychormic pixel imaging technology
• Complete Assignment 4!

For Wednesday, May 7:

• Read the article on pages 57- 63 in the reading packet
• Work on Assignment 4!

For Monday, May 5:

• Midterm break! Wheeee!

For Friday, May 2:

• Assignment 3 is due!
• Read pages 13 - 14 in the reading packet

For Wednesday, April 30:

• Read page 12 in the reading packet
• Assignment 3 is due on Friday

For Monday, April 28:

• Read pages 11 and 31-32 in the reading packet

For Friday, April 25:

• Nothing new to read - work on Assignment 3!

For Wednesday, April 23:

• Finish reading Ch 3 in the Consumer's Guide to Effective Environemental Choices

For Monday, April 21:

• Read pages 9 - 10 and 28-30 in the reading packet
• Start reading Ch 3 in the Consumer's Guide to Effective Environemental Choices

For Friday, April 18:

• Read pages 25-27 in the reading packet
• Complete Assignment 2!

For Wednesday, April 16:

• Read pages 23-25 in the reading packet
• Continue work on Assignment 2

For Monday, April 14:

• Try to complete Assignment 2! (You probably won't be able to figure it all out...)

For Friday, April 11:

• Read pages 17-22 in the reading packet
• Start working on Assignment 2

For Wednesday, April 9:

• Consumer's Guide to Effective Environemental Choices: Ch 2
• Complete Assignment 1, if you haven't already
• Look over Assignment 2

For Monday, April 7:

• Start reading the Consumer's Guide to Effective Environemental Choices: Preface and Ch 1
• Try to complete Assignment 1

For Friday, April 4:

• Read these links about nuclear power in Minnesota:
  Prairie Island Nuclear Waste Storage and the Pairie Island Indian Community
  MN Department of Commerce FAQ on the issue: see in particular pp. 13-16
  An introduction to How Nuclear Power Works
  A word from the current operators of Prairie Island
  A word from Excel energy, the owners of Prairie Island
  A word from one of the key opponents of Prairie Island
• Try to attend Thursday night's panel discussion on nuclear power in Minnesota

For Wednesday, April 2:

• Read course syllabus
• Get class texts at bookstore
• Read pages 1-8 in the reading packet
• Start working on Assignment 1