After rising for nearly two decades, carbon dioxide emissions from United States energy use began to fall sharply and unexpectedly in 2007.
For years now, experts attributed this decrease to the drop in energy demand during the economic recession that began late that year, and to the huge surge in cheap natural gas that displaced coal in our energy mix during this period. But they overlooked another key change that drove the drop in emissions just as much: the rapid rise in renewable energy production.
By 2013, our country’s annual carbon dioxide emissions had decreased by 11 percent – a decline not witnessed since the 1979 oil crisis. Our research shows that the growth of renewable energy sources accounted for 31 percent of that 640-million metric ton carbon drop.
The impact from renewables is just below the 34-percent contribution the switch from petroleum and coal to natural gas made to the emissions decline – a fact that, until now, has previously gone largely unrecognized.
Between 2007 and 2013, wind-generated electricity grew almost five-fold to 168 terawatt hours, enough to power 15 million average American homes. Utility-scale solar grew to 8.7 TWh. At the same time, bioenergy production grew an equivalent of 39 percent to 1,400 TWh, which includes biofuels in the transportation sector.
These positive trends have since continued, in particular for solar and wind energy.
Renewables are the bigger story here
The switch from coal to natural gas certainly contributed to the drop in emissions, but there’s an important caveat here. The climate benefits from this trend are undermined by the presence of methane leakage along the natural gas supply chain, the extent of which is likely underestimated in national greenhouse gas emission inventories.
It’s become clear that incentives to support the expansion of renewable capacity successfully helped reduce carbon dioxide emissions between 2007 and 2013 – and that decreasing costs for renewable energy offer some hope for continued progress under this administration.
GREAT, that things have improved between 2007-2013. I'm curious as to what's happened since 'then' (?).
Either way, tho, the improvement through 2013 means that we have to 'keep on keeping on'---ie., keep moving ahead with renewables and safe, clean energy sources---WITH continued REDUCTION of those ugly fossil fuels, coal, oil, gas, etc.
Thanks, David. We are currently working on an analysis that looks at the years up until 2015 for the power sector, specifically using state level data (2015 being the latest year for which such data is available). We chose to focus on 2007-2013 in this paper to contrast our results from previous findings in the literature.
In reply to GREAT, that things have… by David M. Schee…
Am puzzling over four things: 1. Why would you cut off your analysis at 2013 when much more current data (2016, and even 2017) is available — data that proves your point even more conclusively? 2. Why is nuclear credited with reducing emissions for 2007 to 2013 when its electricity output *declined* (by 2 percent) over that period? 3. Did you not think that “energy efficiency” or even “energy savings” might have been a better term than your “drop in demand”? 4. Did you really not see the Carbon Tax Center’s year-ago report, “The Good News,” which found that “clean energy” (growth in renewables + energy savings) easily surpassed the replacement of coal and oil by natural gas as the major source of CO2 reductions from 2005 to 2016?
Thanks for your detailed comments, Charles. For answers, I refer back to our email chain of last week.
In reply to Am puzzling over four things… by Charles Komanoff
We do have a few things to 'unlearn', however:
Thanks, Karin! In the Northwest, we are primed for politicians and decision makers claiming environmental benefits from fracked gas.
In reply to Thanks for your comment,… by krives
Over the last decade, energy efficiency has come to be seen as a fast, cheap and even profitable way to reduce greenhouse gas emissions. Two years ago, the federal government was hailing a milestone in greenhouse gas emissions in the United States: Carbon dioxide emissions from burning energy — the primary cause of climate change — had fallen for a fifth year in a row, and the carbon intensity of the U.S. economy had fallen faster than at any point in more than six decades.
Lobbyists and the rich are making money by destroying our planet. CONGRESS should be putting a stop to it. I always wonder if the lobbyists and the rich think their families are immune to the effects of climate change.
David Mason CarterMarch 30, 2018 at 7:14 pm