Tuesday, February 24, 2015

2/24/15

Tonight's homework is to complete/revise Assignment 50 and begin working on Part 2 of the Home Electricity Audit - due on Thursday, March 5th. There will be a brief math check-in at the beginning of class tomorrow.

Home Electricity Audit – Part 2

Answer each of the following questions to the best of your ability on a separate piece of paper in complete sentences. SHOW YOUR WORK (especially since there are multiple ways to calculate some of the answers). You can use a calculator to complete these exercises. Your completed product is due on Thursday, March 5th.

Conversion Factors
                                                1 kWh = 3.41 x 103 BTU

                                                1 pound bituminous coal = 12,000 BTU
                                                1 barrel oil = 5.6 x 106 BTU
                                                1 ft3 natural gas = 1,030 BTU
                                                1 g Uranium 235 = 4.0 x 107 BTU

1. Based on your measurements, how much electricity do you consume in a year? NOTE: Based on the information you have, there are multiple ways to answer this question).

2. Suppose the electricity in your region was supplied entirely by the burning of natural gas.

a. How many cubic feet of natural gas is needed to support your energy usage?

b. 1,000 ft3 of natural gas contains about 20.2 kg of methane and when burned completely produce 122 lb of carbon dioxide. How much methane would you consume in one year, and how many pounds of carbon dioxide would you produce?

3. Suppose only coal were used in the generators instead of natural gas.

a. How much coal would be burned to provide your energy?

b. When coal is burned, about 2.3 lb of CO2 is produced for every kilowatt-hour of electrical energy consumed. How much carbon dioxide would be produced by your yearly electricity use?

4. Suppose the electrical power was produced by nuclear power. How much uranium would be needed for your yearly consumption?

Extra Credit 1 – In reality, your electricity comes from a variety of resources, both renewable and nonrenewable. Using data accessed through the class website, more accurately recalculate your values for answer 2-4.

5. Calculate comparative costs for the fuels used to produce your electricity.

a. The cost for uranium oxide (U3O8), the primary nuclear reactor fuel, is $35.50 per pound or about $0.078 per gram. What would be the cost of the uranium to generate your electricity?
b. On average, coal costs about $45.36 per ton. Calculate the cost of the coal needed to produce your yearly electricity.

c. The cost of natural gas for electric utilities, on the average, is about $10.33 per 1,000 cubic feet. How much would it cost to generate your electricity solely natural gas?

d. Con Edison (your electricity supplier) charges about $0.102 per kilowatt-hour of electricity, however consumers can opt to purchase electricity from Green Mountain Energy, which produces electricity via wind turbines for $0.121 per kilowatt-hour. Calculate what your yearly electricity bill with each billing option would be based on your yearly consumption.

Extra Credit 2 – In reality, your electricity comes from a variety of resources, both renewable and nonrenewable. Using data accessed through the class website, more accurately recalculate your values for answer 5a-c.

6. Based on what your have calculated and determined, where do you think your electricity should come from? Support your answer by discussing both economics and environmental impacts such as the method of obtaining or usage of the fuel.

7. Describe and discuss five methods for reducing your electricity consumption.

Extra Credit 3 – For at least two of those methods, calculate by how much this method would reduce your electricity consumption and your electric bill.

Energy Consumption Audit Rubric


Mastery – 4
Proficient – 3
Satisfactory – 2
Needs Revision – 1
Claim about energy usage (Skill)
States clear, nuanced, well-reasoned claim regarding where/how your electricity should be generated
States clear, well-reasoned claim
States a logical, but vague claim
States an illogical or indefensible position
Support of claim (Skill)



Thoroughly supports claim(s) with several detailed, convincing, specific reasons/pieces of evidence as well as refuted counterclaims
Thoroughly supports claim(s) with multiple detailed, specific reasons/pieces of evidence as well as attempts at forming counterclaims/ refutations of them
Supports claim(s) with multiple detailed, convincing specific reason/piece of evidence
Supports claim(s) with reasons/ evidence that are not convincing due to lack of detail, specificity, or clarity OR not having enough pieces of evidence to support each claim
Mathematical fluency (Skill)
Very consistently completes mathematical problems correctly (no more than 2 total errors with no major errors).
Consistently completes mathematical problems correctly (3 or 4 total errors and up to one major error).
Sufficiently completes mathematical problems correctly (5 or more total errors or more than one major error).
Does not sufficiently completes mathematical problems correctly (5 or more total errors and/or more than two major errors).
Demonstrates knowledge of class material (Content)
Very consistently demonstrates deep knowledge of related material by correctly using vocabulary and explaining examples clearly.
Consistently demonstrates knowledge of related material by correctly using vocabulary and explaining examples.
Demonstrates knowledge of related material by using vocabulary and explaining examples, but with some errors.
Does not demonstrate sufficient knowledge of class material through errors or lack of usage/ explanation.
Writing conventions (Work Habits)
Writes elegantly and in a sophisticated manner while very consistently adhering to spelling and grammar conventions. Shows work and answers for mathematical problems clearly and neatly.
Very consistently adheres to spelling and grammar conventions. Shows work and answers for mathematical problems clearly and neatly.
Consistently adheres to spelling and grammar conventions. Shows work and answers for mathematical problems but work is unclear or vague at times.
Mostly adheres to spelling and grammar conventions. Shows work inconsistently for mathematical problems.

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