Carbon Emissions Expected to 9% Decline Since 2007

The Guardian's Grist website reported this week that carbon emissions in the U.S. had dropped 9% since 2007.

While part of this drop is due to the recession, Grist says part of it is from "efficiency gains and from replacing coal with natural gas, wind, solar, and geothermal energy."

The "efficiency gains" claim sounded too good to be true. As I reported in a previous post, America's energy-efficiency improvement from 2007 to 2008 was less than 0.1 percentage point.

So I did some digging.

This month, the Energy Information Administration released a report (pdf) titled "Understanding the Decline in Carbon Dioxide Emissions in 2009." In it, the EIA said it expected CO₂ emissions from fossil fuels in 2009 to be 5.9% below the 2008 level.

70% of the decline in emissions was from:

• Lower energy consumption by the industrial, commercial and residential sectors because of the poor economy
• Utilities switching from coal to natural gas to take advantage of lower natural gas prices -- which had dropped because of the weak economy
• Increased electricity production by non-CO₂-emitting sources like hydropower and wind (these two sources accounted for only 8.3% of electricity generation in 2009)

The other 30% of the drop in CO₂ releases came from declines in petroleum consumption for jet fuel and distillate fuel oil (which includes diesel fuel oil and heating oil). The EIA attributed over two-thirds of this contraction to "economy-related reductions in consumption."

Regarding fuel efficiency, this is what the EIA had to say (emphasis mine):

The data are not yet available to reliably allocate consumption to end-use sectors or the decline in jet fuel, distillate fuel, and other transportation fuel consumption between economy-related declines in demand for transportation services and increases in fuel efficiency, which may be permanent due to technology-related improvements in equipment or transitory because of higher load factors.

In other words, it's too early to declare victory in the drive to fuel efficiency.