ME 217 ENERGY, ENVIRONMENT & SOCIETY

Transcription

1 ME 217 ENERGY, ENVIRONMENT & SOCIETY FALL 2017 MIDTERM TEST OPEN BOOK AND NOTES CALCULATOR ALLOWED PLEASE DISABLE WI-FI AND CELLULAR FUNCTIONS ON YOUR LAPTOPS / TABLETS AND SIMILAR DEVICES PLEASE RETURN ALL TEST PAPERS TOGETHER WITH THE SCANTRON 75 MINUTES 1

2 (1) The electric meter at your house likely reads kwh. This is a measure of (a) electric energy used. (b) maximum electric power used. (c) the monthly charge for electricity. (2) Which statement contradicts the first law of thermodynamics? (a) The sum of all forms of energy in a closed system is constant. (b) Thermal energy can be converted to potential energy. (c) Energy can be destroyed. (3) Which statement contradicts the second law of thermodynamics? (a) Some types of Rankine engine are more efficient than a Carnot engine. (b) Some types of Rankine engine are more efficient than a reversible Carnot engine operating between the same heat source and sink. (c) Heat can flow from a hot reservoir to a cold reservoir spontaneously. (4) Which of the following is not a unit of power? (a) A megajoule. (b) A megajoule / hour. (c) A horsepower. (5) An 80 kg person is exercising on a treadmill, with an incline set to 15 degrees, and a speed of 3.7 miles per hour. What is the power exerted? (a) 336 W. (b) 1.3 kw. (c) 34.2 W. (6) Edison s Pearl St. power station delivered power to a section of Manhattan using: (a) direct current. (b) single-phase alternating current. (c) three-phase alternating current. (7) A limitation of providing electricity with direct current in early power systems is that (a) direct current is unreliable. (b) low voltages required for safety reasons meant high distribution losses over long distances. (c) it is impossible to meter direct current, and charging customers for service is therefore difficult. (8) Consider a 1-mile DC power line with a resistance of 0.01 Ohm, operating at 110 V and delivering 1.1 MW to loads. The electrical loss in the line is: (a) 1 MW. (b) 110 MW. (c) 0.1 MW. (9) Large, centralized plants became prevalent for electricity generation over the past century because (a) electricity could be generated more cheaply than with smaller plants. (b) they could be located away from population centers. (c) both (a) and (b). 2

3 (10) In the current electric system, power transmission lines operate at very high voltages (a) to reduce line losses. (b) to deter people from tapping into the power line and stealing electricity. (c) to deter birds from perching on the wires. (11) A nuclear power plant heats steam to a maximum temperature of 300 C, and rejects heat to a cooling tower at 30 C. The maximum possible efficiency for a plant operating under these conditions is: (a) 52.9%. (b) 33%. (c) 47.1%. (12) The rate of metabolic energy consumption of the average human body at rest is approximately: (a) 2.4 kwh. (b) 100 W (c) 281 kwh. (13) The average rate of energy use for a US resident in the year 2000 was: (a) 281 kwh. (b) 11,730 W. (c) 2.4 kwh. (14) If everyone in the world used as much energy as the average US resident in the year 2000, the total rate of energy consumption for planet Earth would be (a) approximately 8 TW. (b) approximately 82 TW. (c) approximately 1 MW. (15) The population of Earth has roughly doubled in the past 50 years. This corresponds to an annual growth rate of approximately: (a) 200%. (b) 1.6%. (c) 50%. (16) In the logistic model, population growth results from (a) Finite resources, constant growth rate. (b) Finite resources, growth rate proportional to population size. (c) Growth rate proportional to population size only. (17) The ratio of actual electricity produced by a power plant over the course a year and the electricity produced if the plant ran at nameplate capacity all year long is (a) the electric efficiency of the plant. (b) the thermal efficiency of the plant. (c) the capacity factor of the plant. (18) A 100 MW power plant has a capital cost of $200M. If the capital recovery factor is 0.09, and the capacity factor of the plant is 0.5, what is the contribution of the capital cost to the cost of each kwh of energy produced? (a) $0.456/kWh. (b) $0.020/kWh. (c) $0.041/kWh. 3

4 (19) Which of the following is an important technological limitation in the transmission of cheap solar electricity from solar plants located in the desert Southwest to large population centers in the Northeast? (a) Superconducting transmission lines (or lack thereof). (b) The ability to obtain right-of-way to build transmission infrastructure. (c) The fact that the Southwest and the Northeast grids are separate entities. (20) What is an important political-regulatory limitation to the use of offshore wind energy to power cities along the coast? (a) The ability to locate wind turbines in locations where ocean views might be affected. (b) The need to build underwater transmission lines. (c) The need to develop wind turbines capable of surviving in a harsh marine environment. (21) Which of the following technologies currently has the lowest CO 2 emission per unit energy produced? (a) Solar photovoltaic. (b) Natural gas combined cycle power plants. (c) Large-scale wind farms. (22) Why is it that electricity from wind turbines still produces CO 2 emissions if the energy source is the wind only? (a) Because wind turbines require electricity to get the rotation started. (b) Primarily because of the activities required for operation and maintenance. (c) Primarily because of the energy embedded in the manufacturing of the turbines. (23) In a recent poll administered in Canada, the US and the UK, respondents indicated that (a) environmental protection is more important than economic growth. (b) economic growth is more important than environmental protection.. (c) environmental protection and economic growth are equally important. (24) Of the solar energy impinging on planet Earth every day, the greatest proportion is (a) converted to fossil fuels. (b) directly converted to heat. (c) converted to chemical energy through photosynthesis. (25) Petroleum is known to originate from (a) dead wood, covered by water and dirt for hundreds to thousands of years. (b) dead wood, covered by water and dirt for tens to hundreds of millions of years. (c) dead sea creatures, covered by water and dirt for tens to hundreds of millions of years. (26) The typical time needed to turn organic matter into coal is on the order of: (a) 4000 years. (b) tens to hundreds of millions of years. (c) billions of years. (27) The peak oil concept relates to the fact that (a) the world will run out of oil in approximately 50 years. (b) world oil production will peak at some point, and oil will become more expensive to extract and use than other resources. (c) peak oil production has already happened, and production is now declining. 4

5 (28) One of the main assumptions made by Hubbert in formulating his "peak oil" theory is that: (a) the rate of oil consumption follows a bell-shaped curve. (b) the rate of oil consumption increases linearly. (c) the rate of oil consumption is essentially constant. (29) One of the assumptions in Hubbert s theory is that a particular extraction technology improves smoothly and incrementally, not disruptively. A counterexample to that assumption is (a) massive new discoveries in the Alaskan coastal shelf from X-ray tomography. (b) offshore oil extraction. (c) hydrofracturing, combined with horizontal drilling. (30) In hydrofracturing, (a) high-molecular-weight fractions of crude oil are split using steam and made into lighter chains, resulting in more gasoline and diesel. (b) hydraulic pressure is used to fracture an oil-bearing formation, making it easier to extract oil from it. (c) small-scale earthquakes are generated using water pressure to release oil into large salt caverns, for later extraction. (31) Oil shale is a type of rock formation that (a) contains very large amounts of light crude oil. (b) contains kerogen, a solid precursor to liquid hydrocarbons. (c) can be turned into tar sand when ground finely. (32) To reduce carbon emissions, while still exploiting cheap fossil fuels, it is advantageous to rely on: (a) shifting to natural gas for electricity generation (b) shifting to producing liquid fuels by converting coal using the Fischer-Tropsch process (c) using oil for electricity generation. (33) Drivers in cars, trucks, minivans and SUVs put 3.22 trillion miles on the U.S. roads last year. Assuming an average of 26.3 miles per gallon, the average national rate of fuel consumption is: (a) 13.9 million gallons / second. (b) 30.4 tons / second. (c) 3882 gallons / second. (34) 1 kwh of electricity from natural gas, assuming a plant with 50% efficiency, energy content of coal of J/kg, and approximating natural gas with pure CH 4, produces: (a) 0.13 kg of CO 2 (b) 0.36 tons of CO 2. (c) 0.36 kg of CO 2. (35) Mercury emissions from coal combustion are particularly dangerous to humans because: (a) humans are more sensitive to mercury than other species. (b) Mercury emissions settle rapidly in the vicinity of power plants. (c) Mercury accumulates in animal tissue in the food cycle, and humans are at the top of the food chain. (36) SO 2 emissions from power stations can cause, among other things: (a) acid rain. (b) increased planet albedo, increasing surface temperatures (c) impaired motor and cognitive skills, particularly in young children. 5

6 (37) It is difficult to remove NO x compounds from emissions of engines and power plants, because: (a) fossil fuels contain a large amount of Nitrogen. (b) high temperatures are needed for high efficiency, but also result in NO x production. (c) NO x molecules are very small and hard to filter. (38) The 1992 Kyoto protocol was intended to (a) reduce CO 2 emissions globally. (b) reduce NO x emissions in the U.S. (c) reduce emissions of ozone-depleting chemicals. (39) We know that increased atmospheric CO 2 emissions are anthropogenic because: (a) there is no other obvious reason. (b) fluctuations in the ratio of 13 C and 12 C are consistent with burning of fossil fuels. (c) CO 2 from fossil combustion is generally warmer than CO 2 from other sources. (40) Sunspots have the effect of (a) increasing infrared emission from the Sun. (b) decreasing solar radiative flux. (c) increasing solar radiative flux. (41) It is estimated that GHG pollution produces an increase in the solar radiative forcing of approximately (a) 0.15% (b) 1.5% (c) 15% (42) Well-understood radiative forcings to global climate are (a) long-lived greenhouse gases. (b) short-lived pollutants (c) aerosols. (43) Climate models reproduce observed 20th century global warming (a) if, and only if, human-caused forcings (Greenhouse gases and particulate air pollution) are included. (b) pretty much no matter what model parameters are considered. (c) for about half of the models used, the other models show the opposite. (44) One way to sequester CO 2 from the atmosphere is by growing trees. Some of the important limitations are: (a) limitations on land availble for planting trees. (b) competition with food production. (c) both (a) and (b) (45) Carbon Capture & sequestrations is a possible option for removing CO 2 from waste stream. The main limitation(s) to doing this is(are) (a) cost. (b) sites to sequester CO 2. (c) both (a) and (b). (46) The majority of nuclear reactors in the world is of the (a) fusion type. (b) fission, pressurized water type (c) fission, breeder type. 6

7 (47) The number of commercially operated breeder nuclear plants operating today in the world is (a) 438. (b) 100. (c) 0. (48) The main reason for the lack of new nuclear plants in last few decades is: (a) excessive regulation. (b) cost. (c) concerns over nuclear proliferation. (49) The main radiation emitter(s) in spent nuclear fuel after a few hundred years after refueling are (a) fission products. (b) actinides. (c) primarily plutonium. (50) It is estimated that breeder reactor technology could extend the availability of nuclear fuel from approximately 35 years, at current rate of consumption, to about 5000 years. This is possible because: (a) breeder reactors fuse hydrogen into helium, and the supply of hydrogen from water is essentially limitless. (b) breeder reactors produce fissile isotopes by hitting non-fissile 238 U with fast neutrons. (c) breeder reactors produce fissile isotopes by hitting non-fissile 238 U with slow neutrons. 7