Over the past decade and a half, the United States has successfully lowered CO2 emissions by an impressive 32%. Between 2004 and 2019, the total metric tons of annual carbon dioxide produced in electricity generation dropped from 2,544 million to just 1,724 million. This decrease is in conjunction with a population increase of 40 million people, for an even lower emissions rate per capita.
The primary strategic change that has led to significantly lower CO2 emissions is shifting the electricity generation mix away from coal and into natural gas and other renewable energy sources. Over that same time period, natural gas doubled from 19% of total electricity generation to 38%.
- Natural gas-fired generation produces just 43% of CO2/MWh compared to coal-fired generation. This is because coal contains higher levels of carbon content per unit of energy.
- Natural gas burns more efficiently than coal, creating 117 pounds of CO2 per million British thermal units (MMBtu), compared to 209 pounds per MMBtu with coal.
Moving forward, a continued greater reliance on natural gas for electricity generation will help push further reduction in greenhouse gas production.
Rising demand for natural gas to temporarily slow reductions
The U.S. Energy Information Administration has noted that 2021 will likely see a slight return to burning more coal for electricity generation as natural gas prices remain high following strong global demand related to post-pandemic economic activity and other market conditions.
As markets normalize into 2022, previous trends should resume, with the exception that renewables will continue to take greater market share. To take advantage of the rise in renewable energy, more natural gas utilities are partnering with biogas producing industries for the harvesting, cleaning, and piping of RNG to consumers and industrial facilities.
Despite the growing importance of renewable energy such as wind, solar, and nuclear, from an environmental point of view, natural gas has created a far greater impact on emissions reduction in electricity generation over the past 15 years. 65% of the total decline can be directly attributed to from coal-fired to natural gas-fired generation, compared to just 30% reduction for renewables.
These findings further solidify natural gas as the definitive clean energy source in the United States.