Assignment 2

docx

School

University of Southern California *

*We aren’t endorsed by this school

Course

510

Subject

Electrical Engineering

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by ElderAlbatross4090

1. In 2009, the administration of President Obama instituted a so-called “Cash for Clunkers” program. You are to evaluate the effectiveness of the program, which was intended to stimulate the economy and reduce the import of oil. According to the program announcement, an average of $4,000 per car in rebate was offered if a consumer brought in a “clunker” and exchanged it for a new car that would have a fuel efficiency equal to at least 10 miles/gallon better than the car they traded. The total amount of money allocated to the program was $3 billion. a. What reduction in oil import per year, both in terms of barrels of oil and percentage of total import was achieved by the program? b. Assuming that imported oil cost $55 per barrel, how long did it take for the savings in import to equal the investment in the program? c. The energy required to build a new car, called the embedded energy in car construction, has been estimated to be 30,500 kWh/car by Argonne National Laboratory (Burnham et al, 2006, https://greet.es.anl.gov/greet.models ) . The embedded energy comes mostly from coal and nuclear, while the energy saved by the improved efficiency is mostly imported over the life of the car. Estimate how many years it would take to recoup the energy invested in the construction of the car by the savings in energy from the improved mileage of the new vehicle. d. What reduction in CO2 generation did the program achieve? Discuss the effectiveness of the program from an energy perspective and what changes in the program you would recommend to make it more effective. 2. While completing your homework, imagine the study space you are using employs a space heater with a rating of 30 kW, a refrigerator (for snacks) that is rated for 5 kW, and a light fixture with two 100 W bulbs, all operating at a constant rate for the 1.5 hours it takes you to finish. a. What is the total power consumed at any given moment? b. How much energy do you consume to complete the task? c. Assume the utility company charges 6.5 cents per unit of energy in part b, how much did it cost you to complete the assignment? d. If you were willing to pay the utility company $5, what would be the power rating of an additional appliance you could add to your study space? 1 a) What reduction in fuel consumption was achieved with the program? According to bibliography [1] [2] the number of vehicles that were traded in the program were aprox. 700,000. Assuming that if were not for the program, the “clunkers” would have been exchanged 3 years after the program, the reduction in fuel consumption is equal to gasoline that was saved in the miles travelled in these three years. So assuming: - 3 years of extra life for the “clunkers” - 12,000 miles/(year *car) [1] - 15,6 MPG exchanged for 25MPG vehicles (in average) [1] Gallons Saved = Gallons with low MPG vehicles − Gallons withhigh MPGcars vehicles Gallons Saved = miles year / MPG old − miles year / MPG new Gallons Saved = miles year ∗( 1 MPG old − 1 MPG new )

Gallons Saved ≅ 280 gallons /( year ∗ vehicle ) 280 gallons/ (vehicle*year) were saved. Multiplying this result by 3 years of extra life of the “clunkers” that was cut by the program: - 840gallons/vehicle The total amount of gasoline that was saved by the program was 588 million gallons in total (840gallons/vehicle*700,000 vehicles) To evaluate the reduction in crude oil imports, first we need to know how many barrels were imported the year before. For that I consulted the EIA webpage [3] Oil Imports in thousands of barrels 2008 312,536 279,439 298,712 299,373 299,584 300,528 314,092 320,049 253,39 6 312,681 298,309 291,995 3268158 2009 303,136 254,061 290,728 281,218 272,716 274,054 281,911 273,235 277,61 9 265,536 262,201 253,26 3036415 2010 263,249 245,302 289,582 291,766 299,304 297,814 307,894 295,837 276,86 3 264,726 260,966 269,553 3362856 2011 284,678 229,140 284,677 265,167 280,840 277,050 287,563 277,006 267,41 0 276,125 261,729 270,037 3261422 2012 264,348 248,296 271,888 259,077 278,720 275,790 270,061 268,600 251,43 1 251,338 245,487 235,719 3120755 2013 246,629 204,191 232,398 232,807 239,970 231,930 249,788 251,079 237,69 9 231,822 222,248 240,919 2821480 2014 235,269 201,572 225,487 226,639 222,177 212,025 236,534 231,649 224,85 1 221,600 218,845 223,978 2680626 Table 1: U.S. Oil imports in thousands of barrels by year [3] Comparing gasoline saved and crude oil imports: - Gasoline saved: 588 million gallons (14 million barrels in total) Here, we need to note that the reduction is in the consumption of refined gasoline. If we take into account that the imports are of crude oil, we need to know how many gallons of gasoline are obtained with one barrel of crude oil. Again, these will be an average because it depends what type of crude oil it is. But looking at the information provided by the EIA [4]: 42 gallons of crude oil give 20 gallons of motor gasoline. We use that relationship to convert the 14 million barrels of gasoline that were saved into crude oil barrels: The total amount of crude oil that needn’t be imported was: 29.4 million barrels. That is equivalent to 9.8 million barrels/year In percentage of total imports this represents:

Total imports in 2008: - 3,268,158 thousand barrels Import reduction 2009 ( % ) = Total saved Totalimport 2008 ∗ 100 This equation assumes that all the changes in oil imports are because of the program, without taking into account possible variations in production levels, or other factors that might affect it Import reduction 2009 = 9,800 thousand barrels 3,268,158 thousand barrels Import reduction 2009 = 0.3% And now calculating the same for 2010 and 2011: Import reduction 2010 = 9,800 thousand barrels 3,036,415 thousand barrels Import reduction 2009 = 0.32% Import reduction 2011 = Total saved Totalimport 2010 Import reduction 2009 = 9,800 thousand barrels 3,362,856 thousand barrls Import reduction 2009 = 0,29% b) If the imported oil cost is $55/barrel money saved year = barrels saved ∗ cost / barrel money saved year = 9,800,000 barrels year ∗ 55 $ / barrel money saved year = 1,14 billionusd / year Initial investment: 3 billion $

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Recovery of investment [ years ]= Initialinvestmet money saved per year This is without considering the value of money in time, as we don’t have an interest rate to consider. Recovery of investment [ years ]= 3 billion usd 1.14 billion usd / year Recovery of investment [ years ] = 2.65 years c) The energy that was saved per car is equivalent to the reduction in oil consumption of that car. So it is: 280 gallons/year Taking into account that each gallon, when combusted in an IC engine can give 33.7kWh/gallon [5]. Energy saved per car per year = 280 gallons year ∗ car ∗ 33.7 kWh gallon = 9,436 kWh year ∗ car If it takes 30,500kWh to build a car, the time it would take to recuperate the energy would be: Time ¿ recoupenergy [ years ] = Energy invested ∈ buildingthe car Energy rec, per year Time ¿ recoupenergy [ years ] = 30,500 kWh 9,436 kWh / year Time ¿ recoupenergy [ years ] = 3.23 years This isn’t taking into account that some people would have bought a new car but some years later without the program. So that energy wouldn’t have been saved, but rather spent some years later. d) The reduction in CO2 generation that the program achieved can be calculated as: CO 2 Emissions saved = gallons of fuel saved ∗ CO 2 emission per gallonof fuelburned CO 2 Emissions saved = 0.01117 metrictons of CO 2 gallonof fuel ∗ 588 million gallons CO 2 Emissions saved = 6.57 million metrictons of CO 2

The factor of CO2 emissions/ gallon is reported by Leonski et al [1] We can check this number by assuming that all gasoline is octane (C8H18) with a: M r gasoline = 12 ∗ 8 + 18 ∗ 1 = 144 g / mol . M r CO 2 = 12 ∗ 1 + 16 ∗ 2 = 44 g / mol Assuming a density of gasoline of 0.730 g/ml mL of gasoline saved = gallonsof fuelsaved ∗ 3.785 gramsof gasoline saved = mLof gasolinesaved ∗ gasolinedensity [ g mL ] moles of gasoline = grams of gasoline M r gasoline As we would gat 8 moles of CO2 per combustion of mole of gasoline moles of CO 2 = 8 ∗ moles of gasoline gramsof CO 2 = M r CO 2 [ grams mol ]∗ moles of CO 2 We then divide by 1000000 to express it as tons of CO2 and then by 1000000 to have million metric tons Millionmetric tons of CO 2 = 5.0 This result is in the same order as the one we got to with the factor reported by Lensky et al [1]. If we think solely from the energy perspective, the program was not that effective, because even though energy was saved by using vehicles with higher MPG’s, energy was “wasted” in the construction of these cars. And the time to “recover” that energy, is three years, which is the time we estimated owners would have changed their vehicles anyway. To that point, it is arguable if the purchases of new cars would have happened anyway (but some years later) or if people enrolled in the program would have chosen a pre- owned car. On the other hand, if the goal that the program was after was to reactivate the automobile industry, they were effective. The main changes I would implement to the program are: - Reduction of taxes to incentive the oil production industry locally (replace imports). This measure would reduce imports but wouldn’t reduce CO2 emissions. - Raise the minimum MPG of new cars built and give tax benefits to those who buy more efficient cars.

Works Cited [1] Lenski, "The impact of ‘Cash for Clunkers’ on greenhouse gas emissions: a life cycle perspective". [2] G. e. al, "Cash-for-Clunkers Program: Better for Industry than Environment". [3] "EIA," [Online]. Available: https://www.eia.gov/dnav/pet/hist/LeafHandler.ashx? n=pet&s=mcrimus1&f=m. [4] "EIA 2," [Online]. Available: https://www.eia.gov/tools/faqs/faq.php?id=327&t=9#:~:text=Petroleum %20refineries%20in%20the%20United,gallon%20barrel%20of%20crude%20oil. [5] "Energy Education," [Online]. Available: (https://energyeducation.ca/encyclopedia/Miles_per_gallon_gasoline_equivalent#:~:text=When %20testing%20electric%20vehicles%20for,which%20converts%20to%2033.7%20kWh.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

2 a) The total power consumed at any given moment while doing the homework is: Power [ kW ] = Heater Power [ kW ] + Refrigerator Power [ kW ] + Light Power [ W ] ∗ 1 kW 1000 W Power [ kW ] = 35.2 b) The energy consumed to complete the task con be calculated as: Energy [ kWh ] = Power [ kW ] ∗ Time [ h ] Energy [ kWh ] = 52.8 c) The cost of completing the assignment can be calculated as: Cost [ dollars ] = Energy price cents kWh ∗ Energy spent [ kWh ] Cost [ dollars ] = 6.5 cents kWh ∗ 100 cents 1 usd ∗ 52.8 kWh Cost [ dollars ] = 3.43 dollars d) The power rating of an additional appliance can be calculated as: Extra Money = 5 dollars − 3,43 dollars Extra Money = 1.568 dollars = 156.8 cents With 6.5 cents kWh = Extramoney Extra energy willing ¿ spend ¿ Extra energywilling ¿ spend = Extra money 6.5 cents kWh Extra energywilling ¿ spend = 24.12 kWh Extra power [ kW ]= 24.12 kWh 1.5 h Extra power [ kW ] = 16.08 kW