The line graph depicts electricity generation in the United States from four energy sources – coal, natural gas, nuclear power, and water power – along with the overall total, from December 2007 to November 2008.
Overall, coal remained the dominant source of electricity throughout the entire period, while nuclear and water power stayed relatively stable. Notably, both coal and natural gas followed a similar seasonal pattern, with production peaking in mid-2008 before declining towards the end of the year.
In December 2007, coal-generated electricity stood at approximately 170 TWh, before dropping gradually to a low of around 150 TWh in April 2008. It then surged dramatically, reaching a peak of just under 200 TWh in July, after which it fell steadily back to approximately 150 TWh by November. Natural gas mirrored this trend, albeit less dramatically. Having remained relatively constant at just over 50 TWh during the first half of the period, it climbed sharply to nearly 100 TWh in mid-2008, before retreating to roughly 55 TWh by the close of the period.
In contrast, nuclear power and water power exhibited considerably less variation. Nuclear energy maintained a broadly stable level of around 55 TWh throughout, making it the second largest contributor after coal. Water power, meanwhile, was consistently the smallest source, fluctuating modestly between 20 and 30 TWh across the period.
With regard to total electricity output, it began at approximately 350 TWh, dipped to around 300 TWh in spring, and then climbed sharply to a peak of nearly 400 TWh in July. This was followed by a steady decline to just above 300 TWh by November 2008, largely reflecting the trajectories of coal and natural gas production.