The provided bar graphs delineate the quantities of electricity generated from both renewable and non-renewable energy sources in the United States during the years 2009 and 2019.
Overall, there is a notable decrease in electricity generation from non-renewable sources, particularly coal and petroleum, while renewable energy generation has experienced substantial growth, particularly in wind and solar energy.
Focusing first on non-renewable energy sources, coal remained the predominant contributor in 2009 with an output of 1,756 billion kilowatt-hours; however, this figure plummeted to 966 billion kilowatt-hours by 2019. Petroleum similarly saw a decrease from 57 billion kilowatt-hours in 2009 to 40 billion kilowatt-hours in 2019. In contrast, natural gas displayed impressive growth, with generation escalating from 921 billion kilowatt-hours to 1,582 billion kilowatt-hours over the same period. Nuclear energy experienced a modest increase, rising from 799 billion kilowatt-hours to 809 billion kilowatt-hours between these two years.
On the other hand, renewable energy sources exhibited a remarkable increase in electricity production, with total output escalating from 437 billion kilowatt-hours in 2009 to 720 billion kilowatt-hours in 2019. Hydroelectric power remained constant at 273 billion kilowatt-hours, while wind energy saw a significant surge from 94 billion kilowatt-hours to 300 billion kilowatt-hours. Solar energy also transformed dramatically, rising from a mere 1 billion kilowatt-hours to 73 billion kilowatt-hours. Conversely, geothermal energy and biomass experienced minor fluctuations, contributing 15 billion kilowatt-hours and 54 billion kilowatt-hours, respectively, in 2009, with slight increases to 16 billion kilowatt-hours and 58 billion kilowatt-hours by 2019.