Figure 1 shows annual percentage contributions to total global energy consumption by fuel type since 1965. I plotted it up to see if it contained any hidden messages about the world energy market that had escaped my attention (the data used to construct all the graphs presented in this post are from the BP 2014 Statistical Review):
Figure 1: Percent contribution to global energy consumption by fuel type
At first glance there was nothing new. Oil‘s contribution peaked in 1973 and has been trending down ever since. Coal’s contribution declined rapidly between 1965 and 1977, but then it flattened out and after 2002 began to stage a comeback. Gas slowly built market share before 2002 but has stabilized since then. Hydro’s contribution has hardly changed, nuclear forged ahead until 1985 but then flattened out before beginning to fall away, and other renewables (wind, solar etc.) have barely lifted off the zero line.
Then I noticed an interesting feature. The percentage contributions of oil and coal tend to move in opposite directions. Coal goes down, oil goes up. Oil goes down, coal goes up. Oil goes flat, so does coal. But neither oil nor coal show a clear overall relationship with the third major source of energy, natural gas. The suggestion is that oil and coal have been substituting for each other, with coal replacing oil or oil replacing coal depending presumably on market conditions at the time, but with gas remaining largely unaffected.
Let’s look at this a little more closely.