US reducing power sector CO2 emissions while growing economy: study

The US power industry has been making steady progress reducing greenhouse gas emissions, with power sector carbon dioxide emissions decreasing about 10% between 2019 and 2020 because of a mixture of pandemic impacts, energy efficiency and fuel switching away from coal, a July 20 report said.

"The coronavirus pandemic may have been a contributing factor, but the drop in emissions in 2020 is part of a long-term trend fueled by increased renewable generation and coal-to-gas transitions," according to a statement released with the report titled "Benchmarking Air Emissions of the 100 Largest Electric Power Producers in the United States."

'Dramatic shifts'

This year's report, which has been prepared since 1997, highlighted several "dramatic shifts," as the share of power produced by non-hydro renewables increased 20% from 2019 levels and the share from coal-fired generation decreased by roughly 17%, the statement said.

The report was prepared by sustainability nonprofit Ceres; Bank of America; power producers Entergy and Exelon; and environmental group Natural Resources Defense Council. It was authored by consultant M.J. Bradley & Associates.

US power companies face intensifying pressure to decarbonize amid a steady stream of net-zero emissions commitments and regulatory or legislative actions at the state, and increasingly under the Biden administration, the federal level.

An S&P Global Platts analysis earlier this year showed the US now has at least 20 states, plus the District of Columbia, with aggressive plans in the works for 100% renewable power, carbon-free power or net-zero emissions, roughly double the number from a year ago, while 12 states have not initiated any clean energy plans.

The 100 largest power producers in the US own nearly 3,500 power plants and account for more than 80% of the sector's power generation and reported air emissions, according to the benchmarking report, which relies on data from state agencies, along with the US Environmental Protection Agency and US Energy Information Administration.

Company, state-level data

Of the top 100 US power producers, 85 generated power from zero-carbon resources in 2019, accounting for 83% of the national total generated from zero-carbon resources including nuclear power, hydropower and renewables, the report said.

The top five producers of zero-carbon power in 2019 were Exelon, NextEra Energy, Duke Energy, Tennessee Valley Authority and Entergy.

Several of those generators also reported the lowest CO2 emissions rates, though that data set only includes privately/investor-owned power producers and does not cover public power producers like federal power authorities, municipal power districts or cooperatives.

The top five generators with the lowest CO2 emissions rates in 2019 were Exelon, Public Service Enterprise Group, NextEra Energy, Entergy, and Dominion Energy, according to the report.

From 2000 to 2020, US power sector CO2 emissions decreased 37%, while the gross domestic product grew 40%, which shows that emission can be cut while increasing economic growth, the authors said.

And over the same period, generation from renewable energy resources more than doubled. In 2020, renewables and other zero-carbon resources generated roughly 38% of US electricity, and of those zero-carbon resources, nuclear made up 52%, renewables 29% (wind, solar, geothermal) and hydropower 19%, according to the report.

State-level CO2 emissions data also varied based on the size of total emissions compared with individual state-level generation fuel mixes.

"The total emissions numbers reflect the total amount of CO2 emitted from all power plants in the state, so larger states like Texas, tend to have more emissions," Dan Bakal, Ceres' senior director of electric power, said in an email.

"However, California does not show up in the top five due to the significant amount of renewable energy and natural gas generation," he said.

"Meanwhile, the CO2 emissions rate shows the average amount of CO2 emitted by all power plants in the state per megawatt-hours produced, and as a result, states with a lot of coal and gas generation are on that list, even if they are smaller or have less generation," Bakal said.

For example, facilities in Texas produced 483 million MWh compared with just 42 million MWh in Wyoming, but, only about 19% of the power produced in Texas comes from coal, compared with 83.9% in Wyoming, he added.

Also, facilities in California produced 202 million MWh, but with no coal, and more than half coming from zero-emission sources, Bakal said.