Emissions of Greenhouse Gases Report

Date: December 3, 2008
Source: Energy Information Administration (www.eia.doe.gov)
Complete Printer-Friendly Version (64 pages)

Ednote: The Kyoto Protocol mandated a voluntary reduction of GHG’s by signatory countries. Time limits were set to give those countries non-economically compromising compliance adjustment periods. The following data from a supposedly reliable source would seem to indicate that progress is slow if at all. Digest this date for a few minutes it is quite illuminating if you connect the data to the dire warnings of Climate Change professionals.

The President issued a directive on April 15, 1999, requiring an annual report summarizing the carbon dioxide (CO₂) emissions produced by the generation of electricity by utilities and nonutilities in the United States. In response, the U.S. Department of Energy (DOE) and the U.S. Environmental Protection Agency (EPA) jointly submitted the first report on October 15, 1999.

Carbon Dioxide Emissions

• Total U.S. carbon dioxide emissions in 2007 increased by 75.9 million metric tons (1.3 percent) compared with 2006 emissions (see Figure 5 on right), to 6,022 million metric tons (MMT). The increase offset a 1.4-percent drop in 2006 (to 5,946 MMT), raising the total back close to the 2005 level (6,032 MMT). 

• The important factors that contributed to the increase in carbon dioxide emissions in 2007 included: unfavorable weather, with both heating and cooling degree-days above 2006 levels (see discussion on "Weather Effects on energy-Related Carbon Dioxide Emissions, 2006 and 2007"); and the combination of a 2.5-percent increase in electricity demand and a 14.2-percent decline in hydropower generation that resulted in a 2.9-percent increase in emissions from the electric power sector.

• Energy-related carbon dioxide emissions account for 98 percent of U.S. carbon dioxide emissions (see Table 5 below). The vast majority of carbon dioxide emissions come from fossil fuel combustion, with smaller amounts from the nonfuel use of energy inputs, and the total adjusted for emissions from U.S. Territories and international bunker fuels. Other sources include emissions from industrial processes, such as cement and limestone production.

Data for all years 1990-2007

Figure data

Energy-Related Emissions

• Energy-related carbon dioxide emissions account for more than 80 percent of U.S. greenhouse gas emissions. EIA breaks energy use into four end-use sectors (see Table 6 below), and emissions from the electric power sector are attributed to the end-use sectors. 

• Growth in energy-related carbon dioxide emissions has resulted largely from increases associated with electric power generation and transportation fuel use. All other energy-related carbon dioxide emissions (from direct fuel use in the residential, commercial, and industrial sectors) have been either flat or declining in recent years (see Figure 6 below).

• Reasons for the growth in electric power and transportation sector emissions include: increased demand for electricity for computers and electronics in homes and offices; strong growth in demand for commercial lighting and cooling; substitution of new electricity-intensive technologies, such as electric arc furnaces for steelmaking, in the industrial sector; and increased demand for transportation services as a result of relatively low fuel prices and robust economic growth in the 1990s and early 2000s.

• Other U.S. energy-related carbon dioxide emissions have remained flat or declined, for reasons that include increased efficiencies in heating technologies, as well as declining activity in older “smokestack” industries and the growing importance of less energy-intensive industries, such as computers and electronics.

Data for all years 1990-2007

Figure data

Weather Effects on energy-Related Carbon Dioxide Emissions, 2006 and 2007

Annual variations in CO₂ emissions in the residential and commercial sectors over the 2005-2007 period illustrate the impacts that changes in weather can have on emissions in those sectors. Total energy-related CO₂ emissions for all the end-use sectors combined (residential, commercial, industrial, and transportation) were down in 2006 by about 69 million metric tons (MMT), but in 2007 they were up by about 84 MMT, inviting the question: Why are these years so different from each other?

It is difficult to estimate the relative importance of the different factors that affect year-to-year changes in emissions. Since 1990, energy-related emissions have grown on average by about 1.0 percent per year. At current emissions levels that would mean about 60 MMT added per year. With U.S. GDP growing by 2.8 percent in 2006 but by only 2.0 percent in 2007, why was 2006 emissions growth so far below average (-69 MMT) and 2007 growth above average (+84 MMT)?

One of the most important factors causing deviations from average emissions growth is weather. The table on the right shows emissions from energy use for heating and cooling in the residential and commercial sectors for 2006 and 2007, and weather adjustments for both sectors, based on estimates from EIA’s Annual Energy Outlook 2008. In 2006, emissions attributable to space heating and space cooling both were lower than in 2005; in 2007, both were higher than in 2006. The annual variations can be estimated more precisely by using changes in heating degree-days (HDD) and cooling degree-days (CDD). In 2006, both HDD and CDD were down relative to 2005, reducing both space heating and cooling requirements; in 2007, both HDD and CDD were up relative to 2006, increasing demand for both heating and cooling.

In the residential sector, CO₂ emissions related to heating and cooling in 2006 were estimated to be about 48 and 13 MMT lower than in 2005, respectively, for a total weather effect of -61 MMT. In the commercial sector, emissions related to heating and cooling in 2006 were 10 and 4 MMT lower than in 2005. Thus, for both sectors, emissions in 2006 were about 76 MMT lower than they would have been without the weather effect. The effect is not insignificant: when 2006 emissions in the two sectors are adjusted for the weather effect, the result shows an increase of 7 MMT from 2005 to 2006. Similarly, for 2007, the weather effect accounts for about two-thirds (56 MMT) of the total increase in residential and commercial sector CO₂ emissions relative to 2006.

With the adjustments for weather, the growth of total energy-related CO₂ emissions in both 2006 and 2007 is below the 1.0-percent average growth rate for the 1990-2007 period. Other important factors in year-to-year changes in CO₂ emissions include total and relative fuel prices, efficiency of electricity generation and the energy-intensive industries, and the availability of hydropower, nuclear power, and other low-carbon energy sources, as well as overall economic growth.

Residential Sector

• Residential sector carbon dioxide emissions originate primarily from:
  • Direct fuel consumption (principally, natural gas) for heating and cooking
  • Electricity for cooling (and some heating), for lighting, and increasingly for televisions, computers, and other
  • household electronic devices (see Table 7 below).

• Energy consumed for heating in homes and businesses has a large influence on the annual fluctuations in energy-related carbon dioxide emissions.
  • The 6.5-percent increase in heating degree-days in 2007 was the second-largest year-to-year increase over the period from 1990 to 2007 (see Figure 7 below).
  • Although annual changes in cooling degree-days have a smaller impact on energy demand, the 2.2-percent increase in 2007 contributed to the upward pressure on electricity demand.
  • Weather was a key factor behind the 4.3-percent increase in carbon dioxide emissions from the residential sector in 2007.

• In the longer run, residential emissions are affected by population growth and income. From 1990 to 2007:
  • Residential sector carbon dioxide emissions grew by an average of 1.6 percent per year.
  • U.S. population grew by an average of 0.9 percent per year.
  • Per-capita income (measured in constant dollars) grew by an average of 1.7 percent per year.

Data for all years 1990-2007

Figure data

Emissions of Greenhouse Gases Report
Complete Printer-Friendly Version (64 pages)