Energy costs vary greatly with energy source: coal @ $25,00/ton. gasoline @ a pomp price of $2.00/gal, and electricity @ $0. 1000/k Whr. Conventional practice is to put these on a common basis by expressing them in $GJ-1. [A gigajule is approximately 106(Btu).] For this purpose, assume gross heating values of 29 MJ kg-1 for coal and 37 GJ m-3 for gasoline.
(a) Rank order the three energy sources with respect to energy cost in $ GJ-l.
(b) Explain the large disparity in the numerical results of Part (a). Discuss the advantages and disadvantages of the three energy sources