U.S. Carbon Emissions A-Fallin'

Good news, America: your carbon emissions are going down!

The U.S. Energy Information Administration    G just released an analysis of the nation’s annual energy-related carbon emissions between 2000 and 2009.  Over this period, total emissions dropped by 7.4 percent while per capita emissions fell 15 percent to an average of 17.6 metric tons per person (#1 among the world’s top economies).

Of course, there’s a little more to the story because the greatest drop in emissions was seen in 2009, just when the recession was in full effect.  But as one economist from the EIA explained, the recession isn’t the only reason for the overall drop in emissions.   "We're moving away from the industry-heavy economy to more information-based economy," he said. "So our energy consumption per dollar of GDP is going down."

Before we take a look at some of the report’s highlights, it’s important to point out that the EIA calculated emissions based on the location where the fossil fuels were used, not where the resulting electricity was consumed.

To illustrate, consider a few important questions for one of America’s coal-baskets, Wyoming (coming in at a whopping 117 tons of CO2 per capita):

How large is the population? The smallest in the country.
Is the economy based on industry or is it more commercial?
Oh, it’s industrial.
Is state a net exporter or importer of electricity? According to the EIA report, it’s a large exporter of coal-generated electricity.

All of these factors make Wyoming appear as if its emissions impact is much greater than its neighboring states, even though much of its electricity is in fact consumed in those same neighboring states.  In other words, don’t get too smug about your low CO2 emissions, Idaho.

On to the highlights:

Total State Emission Levels (in 2009)
Greatest Total Emissions: Texas (605 million metric tons). You know the drill: everything’s bigger in Texas and so on.  The Lone Star State did have the greatest absolute drop in emissions over ten years, however, at 52 million metric tons. Texas forever!

Per Capita CO2 Emissions
Lowest: New York (9 metric tons per capita). Lots of mass transit, lots of apartments and high electricity rates tend to inspire energy efficiency.
Highest: Wyoming (117 metric tons per capita). The second-largest energy producer in U.S., smallest population in the country, really cold winters.

Emissions by Fuel
Highest Share of CO2 Emissions from Coal: West Virginia (79 percent). Coal country, of course.
Highest Share of CO2 Emissions from Petroleum:Vermont (93 percent). But Vermont also emits the least amount of CO2 at 6.3 metric tons per year. So the Green Mountain State gets a pass.
Highest Share of CO2 Emissions from Natural Gas: Alaska (48 percent).  Lots of energy production in Alaska. Maybe a new natural gas pipeline, too?

Emissions by Sector
Lowest Residential CO2 Emissions: Hawaii (0.1 million metric tons). The dominant share of energy emissions comes from petroleum, but there’s not much need for heating oil in the 50th State.
Largest Transportation CO2 Emissions: California (218 million metric tons). You might be familiar with California’s freeway traffic?
Largest Commercial CO2 Emissions: New York (26 million metric tons). A big information-based economy (all that downloading, streaming and Tweeting relies on data centers that eat up to a lot of megawatts).

Carbon Intensity of Energy Supply (the amount of carbon emitted per unit of energy produced)
Highest Carbon Intensity: West Virginia.  Them again?  Yes, and number two is, of course, Wyoming.  Those states where coal is the dominant fuel tend to have high carbon intensity.
Lowest Carbon Intensity: Vermont again, this time because it depends a lot on nuclear and hydroelectric sources. Oregon and Washington aren’t far behind thanks to their dependence on hydropower.

What might affect United States energy-related carbon emissions in the next ten years?  Keep your eye on the economy (Will there be a rebound soon? Will the industrial economy continue to fade?), greenhouse gas legislation (No, not federal, but some states are active) and the momentum shift away from coal and petroleum towards natural gas and renewables (and the nuclear wild card).

The slimmer carbon profile is certainly a good thing, but once the economy gets going again Americans will have to actively pursue a clean energy economy to keep dropping millions more metric tons.