Other than a slight uptick from 2012 to 2013, U.S. carbon dioxide emissions have been on a slow decline since 2007. And according to a new report by Greenpeace, 70 percent of that drop was thanks to renewables and energy efficiency.
The data crunching, carried out by Greenpeace energy analyst Lauri Myllyvirta and published by the group’s Energydesk site, dug into the dramatic 21 percent drop that U.S. coal consumption saw from 2007 to 2013. That was accompanied by a 16 percent fall in the country’s carbon emissions over that same six-year period. Natural gas generation also spiked over 23 percent in that time span, which has led many observers to credit the North American shale fracking boom with the drop in the emissions that contribute to global warming and climate change.
But burning natural gas also releases carbon dioxide, just in smaller amounts. So while it made up 44 percent of the hole in energy consumption coal left behind, it only accounted for 30 percent of the drop in carbon emissions. According to Myllyvirta’s analysis, growth in renewable generation — and wind in particular — contributed to 40 percent of the fall in emissions, and rising use of energy efficiency covered the other 30 percent.
“The supposed climate benefits of fracking have been a big selling point for the shale lobby, but this myth has now been cut down to size by compelling new evidence,” said Myllyvirta. “Our analysis shows that it was the clean tech boom, not the fracking rush, that slashed the bulk of carbon emissions from the US power sector.”
Renewable energy consumption grew just over 48 percent from 2007 to 2008, making up 35 percent of the energy consumption coal left behind. Rising energy efficiency measures made up the remaining 21 percent in energy consumption.
The Energydesk study also did not account for any leakage that may occur from the natural gas industry’s infrastructure. That means natural gas is almost certainly doing considerably less good on the global warming front than even Greenpeace’s numbers suggest, as the methane that makes up natural gas is, pound-for-pound, a far more potent greenhouse gas than carbon dioxide. Multiple studies suggest the leakage is so bad it completely undoes any climate advantage to burring natural gas. And a new study published by Nature last Wednesday concluded that, absent a big regulatory crackdown on those leaks, burning more natural gas won’t work as a method to curb global warming.
Greenpeace also pointed to a recent report by Alliance Bernstein that anticipates coal use in the U.S. will rise by another 7 to 25 percent by 2020, thanks to both new federal regulations and state-level renewable energy policies. The bulk of coal plant retirements is expected in 2015 as federal rules to cut mercury and other air toxins kick in, and coal generation has been dropping for years as natural gas has cut into the power market and the raw physical limits of mining harder-to-reach deposits have begun to assert themselves.
The Bernstein analysis suggests renewables could account for 10 percent of U.S. power by the end of this decade, though Greenpeace noted that if renewables stick to their current pace of growth they could make up 20 percent of the mix by that time. Whether they’ll hit that mark is currently uncertain, however. Investment in renewables grew at its fastest pace in 2013, but it’s expected to plateau after that due to the failure of governments around the world — and especially in the United States — to build in a reliable pricing mechanism for carbon emissions.
Meanwhile, the Union of Concerned Scientists recently concluded that the new federal cuts to power plant emissions were not as ambitious as they could be. Instead of aiming for a 30 percent cut from the industry by 2030, emissions could be cut 40 percent with little to no economic drag. The International Energy Agency also anticipates that energy efficiency alone could get the world 40 percent of the emission reductions it needs to stay under 2°C of global warming.
“Ahead of a crunch year for global negotiations on a new climate deal, all the evidence points to clean technologies and smarter energy use as the most effective solutions to tackle climate change,” Myllyvirta continued. “Our political leaders will do well to remember this.”