Dive Brief:

• The declining use of coal last year sent Arkansas carbon emissions lower than would be required by the Clean Power Plan in the rule's final year of implementation, the Arkansas Democrat-Gazette reports.
• The newspaper said carbon emissions dropped last year to 30.1 million tons, an almost 25% decline from 39.7 million tons in 2014. By 2030, the CPP would limit Arkansas emissions to 30.6 million tons.
• Arkansas' emissions decline is a strong example of the broad impacts of declining coal use. Earlier this month, the U.S. Energy Information Administration reported the United States had reduced its carbon dioxide emissions by 12% below 2005 levels last year.

Dive Insight:

The Arkansas Democrat-Gazette has a lengthy piece on the state's decline in emissions and how lower coal use could help it meet the Clean Power Plan — despite a longtime reliance on the fuel and official opposition to the new rules.

But while Arkansas' emissions decline reflects a national trend, as renewable energy and cheap gas edge out coal, the size of the decline is surprising considering the state added a new coal plant in late 2012.

"It's economical to dispatch natural-gas production," Stuart Spencer, director of the Arkansas Department of Environmental Quality's air division, told the newspaper, also adding that renewable energy was playing a key role.

"When all those factors are added together seeing this reduction in carbon emissions, I can't say that it will stick, but that's what you're seeing now," he said.

While nationally, emissions increased in 2013 and 2014, the changing power mix had a large impact last year. Coal was still the dominant generation fuel, but cheap natural gas has almost changed the typical balance. Gas-fired power plants generated more energy than coal did in seven months last year, and the final generation output was close: 1,356,057 GWh for coal, and 1,335,068 GWh for gas.

EIA pointed out that the decline in emissions last year from the power sector was even more significant given the growing economy. "The largest annual decline in energy-related CO2 emissions in the past decade occurred in 2008–09 during the recession," EIA said, but "overall, the U.S. economy has grown even as energy-related CO2 emissions have fallen."

Last year, the United States used 15% less energy per unit of Gross Domestic Product (GDP) and produced 23% fewer energy-related CO2 emissions per unit of GDP, compared with the energy and emissions per dollar of GDP in 2005.

While environmentalists welcomed the decline in carbon emissions, many worry that increased methane leakage from the natural gas drilling and transport could cancel out climactic benefits over burning coal. In the short term, methane is a greenhouse gas over 80 times more potent than CO2. Last week, the EPA announced new regulations on methane emissions aimed at limiting natural gas leaks.