Coal and natural gas are the two predominant forms of fossil fuel used around the world to generate electricity. in this problem, we will examine emissions from coal, and consider how that compares to natural gas. assume energy density for coal and natural gas to be 29.3 and 55.0 mj/kg respectively.
a) based on an approximate formula for coal, ch0.8o0.2, and an approximate formula for natural gas, ch4 (i. e., methane), write two balanced equations, one for each fuel, for complete combustion in oxygen.
b) in 2016, the united states generated 1,300 twh of electricity from coal. in the same year, china generated 3,900 twh of electricity from coal. assume that the average efficiency of coal-fired plants in the us and china is 33%.
i. how much coal (in kg) was used to produce electricity in each country? (8 points)
ii. the u. c. berkeley campanile (the clock tower in the center of campus) has a base of 93 m2 and a height of 94 m. *if you built them out of solid coal, a) how many campanile-sized rectangular towers could you make with the u. s. and china’s combined 2016 coal use, and b) if you stacked them on top of each other, how tall would the tower be (in km)? assume coal has a density of 2,200 kg/m3.
iii. using the information above (coal chemical formula, specific energy of coal, and assuming pure oxygen combustion, how much co2 (in metric gigatons) was released into the atmosphere as a result of burning the coal used in the u. s. and china for electricity production?
iv. if world annual co2 emissions from fossil fuel were 36 gt(co2), what percentage was attributable to u. s and chinese coal burning for electricity?
v. if the u. s. and china had generated the same amount of electricity with natural gas plants operating at 35% efficiency, instead of coal, how much less co2 would they have emitted (in gt)? (note: we have given you an energy density by weight above, but natural gas is usually measured by volume (l or m3 rather than weight) (gut check: the percent reduction you get should be about accurate compared to real-world conditions).
c) now assume that all the coal from part b. has a sulfur content of 1% (by mass).
i. calculate the total mass (in metric tons) of so2 produced by the coal power plants. assume that all sulfur emerges in the form of so2.
ii. determine the new chemical formula for this coal, and rebalance the combustion equation using this new chemical equation
iii. the total nameplate capacity of all coal-fired power plants in the united states in 2016 was about 340 gw. what was the average capacity factor of coal power plants in 2016?