Starting the year at 100 points in an energy performance index, benchmark European power and gas prices saw the closest correlation and, although they diverged a little during the middle of the year, they converged again in the last few months of 2011 to end up just below 100 points.

Coal saw the smallest movements, ranging between 90 and 105 points throughout the year, while carbon prices saw by far the highest volatility, first rising to above all other products to 125 points, before crashing from the middle of the year to a low of under 50 points. By comparison, benchmark Brent crude oil was on track to post a 13 percent gain for 2011.