Fossil fuel power plants operate by using the energy from burning fuel such as coal to boil steam. A coal power plant releases approximately 0.441 kg of CO2 to the atmosphere for every MJ of electricity generated. Internal combustion engines burn gasoline (or diesel) to generate shaft power to drive automobiles. Typically, about 15% of the heat from combustion is lost and about 20% of the remaining energy is converted to shaft power.
Gasoline releases approximately 47 MJ for every kg burned, and is composed of 89% carbon by mass. Compute the mass of CO2 produced for every MJ of shaft power produced. Compare the CO2 emissions for power plants and internal combustion engines. If the car can travel 25 miles on a gallon of gas, compute the mass of CO2 expelled when travelling 100 miles.
A plug-in electric vehicle uses electricity to charge an onboard battery which converts the stored energy to shaft power to drive the vehicle. Battery energy is converted to shaft power at efficiencies around 80%. Transmission losses of 6% occur when transmitting electricity from the power plant to the charging station. Assuming the electric vehicle requires the same shaft energy as the internal combustion automobile to travel 100 miles, calculate the mass of CO2 expelled during electricity generation for the 100 mile trip. Compare the CO2 emissions from internal combustion engines and electric vehicles. In order to perform the calculations, find the percentage of electricity generated from fossil fuels in Georgia and assume all fossil plants exhibit similar performance as the coal plant described here. As a comparison find the fractions of energy generated by nuclear, fossil, and renewable sources for Georgia, Washington state, and the national average.