Natural Gas Integral to Progress in Reducing CO2 Emissions

Mark Green
Posted October 2, 2020

Growing natural gas use in the U.S. power sector continues to be an important factor in decreasing the country’s energy-related carbon dioxide emissions, a critical greenhouse gas in the climate conversation.

This is seen in the latest U.S. Energy Information Administration (EIA) emissions report, which showed that these CO₂ emissions decreased 2.8% in 2019 compared to 2018, largely thanks to changes in the electricity fuel mix.

Coal-related emissions declined 15% last year, reflecting a decline in coal’s share of U.S. power generation (falling from 27% to 23%). Natural gas is the leading fuel for generating electricity, its share of the mix rising to 38.4% in 2019 from 35% in 2018. (Nuclear accounted for 19.6% of generation while 9% was generated by wind and solar). Coal’s downward trend continued and even accelerated through the first two quarters of 2020, while natural gas’ share in the generating mix remained steady despite falling overall power demand.

As for CO₂ emissions, let’s look at a couple of charts. First, energy-related CO₂ emissions since 1990:

The data above and throughout EIA’s emissions report are from the Monthly Energy Review for August. The black line is total energy-related emissions; the brown bars show percentage change from year to year.

There’s a decrease of 150 million metric tons (MMmt) from 2018 to 2019. Since 2007, energy-related CO₂ emissions fell in eight of the 12 years. While total CO₂ emissions by weight in 2019 were about the same as in 1990, keep in mind that the U.S. population and economy have grown significantly over the period.

The overall carbon intensity of the U.S. economy – total carbon by weight per unit of economic activity – declined 4.9% in 2019, EIA says, resulting from a decrease in energy intensity – measuring the output of an activity to the energy input to that activity – reflecting energy efficiency and the structure of the economy. The economy’s lower carbon intensity also resulted from a decrease in the carbon intensity of energy consumed, the report said. EIA:

After the U.S. economy began to recover in 2010, the divergence of CO₂ emissions from population growth continued as a result of decreases in the carbon intensity of energy consumption … Decreases in carbon intensity – the amount of carbon by weight emitted per unit of energy consumed – were driven by: increases in natural gas production from shale and tight resources that lowered the cost of natural gas production and made it cost competitive with coal for electric power generation [and] policies that encouraged the use of renewable energy …

Again, the important role of abundant, affordable natural gas is apparent. Here’s another chart, an updated version of one we’ve used before, showing the relative roles of natural gas and renewable energy in reducing CO₂ emissions from electricity generation since 2005:

This chart, too, reflects reduced use of coal in the power sector, which has lowered the carbon intensity of that sector. You can see that over the time period, CO₂ emissions reductions from fuel switching, from coal to natural gas and renewables, totaled 5,475 MMmt (cumulative). Of those emissions reductions, EIA calculated that natural gas (blue bars) accounted for about 61% of the savings vs. about 39% for renewables.

The big takeaway here is the significant progress in reducing emissions of a key greenhouse gas. U.S. energy-related CO₂ emissions are at their lowest levels in a generation. No other nation has reduced emissions more than the U.S. since 2000, according to the International Energy Agency.

Increased use of natural gas is integral to that progress, yet through innovation and technology – especially carbon capture, utilization and storage (CCUS) – more advances are possible. Also, partnering the reliability and quick ramp-up ability of natural gas is key to the growth of intermittent fuel sources including wind and solar.

Keeping the big picture trend lines going in the right direction includes making sure domestic natural gas continues to be abundant and affordable. Stephen Comstock, API vice president of policy, economics and regulatory affairs:

“This data is important to understand that progress is being made towards energy solutions that can address emissions and consumer expectations. Our goal is to support the problem solvers in our industry to continue to improve upon this trend by developing policies and initiatives for tomorrow’s energy needs.”