Global GHG emissions from energy use and production far outweigh emissions from other activities. The industrial processes, agriculture, land-use change and forestry, and waste management sectors together account for 37 percent of all global GHG emissions in the accompanying pie chart. However, a significant proportion of the emissions from agriculture and from land-use change and forestry involve fossil fuel consumption, so the percentage of emissions from energy is greater than the graphic implies. Consequently, far more than two thirds of all GHG emissions result from energy use and production.
In the pie chart, electricity and heat production is clearly the largest emitter of GHGs, being responsible for over one quarter of total emissions. Most of these emissions are attributable to society’s dependence on coal and secondarily on natural gas. The remaining energy categories –– manufacturing and construction, transportation, and “other” –– each contribute approximately equal proportions of the global GHG emissions.
Going beyond this particular graphic, when compiling the national GHG emissions inventory, the US breaks its energy sector emissions into three broad categories: mobile sources, stationary sources, and fugitive sources.
The stationary sources category is large and includes many activities.
There are many other important categories of GHG-producing activities:
Even so, these enterprises consume huge amounts of electricity, and most of this electricity comes from fossil fuel-powered power plants, so these categories are indirectly responsible for a very large proportion of GHG emissions.
In addition to transportation and stationary sources, fugitive CH4 emissions from coalmines and from oil and natural gas drilling sites, as well as from natural gas pipelines, were thought to be a relatively small source of GHG emissions. Recent work, however, suggests that fugitive emissions may in fact be a major source of atmospheric CH4, so this part of the energy sector is coming under increased, intense scrutiny.
The relationships among energy production, energy storage and distribution, energy marketing, and energy demand and consumption are extremely complex. Thus, trying to pin GHG emissions to any one component in this complex web is arbitrary. Indeed, calculating emissions from the energy sector is fraught with error because of this complexity. It is best to think not in terms of exact proportions of GHG emissions from any one activity or subsector, but in terms of which categories are the big players.
Links
[1] http://www.wri.org/our-work/project/earthtrends-environmental-informationupdates/node/296
[2] https://creativecommons.org/licenses/by/4.0/
[3] https://www.carbonbrief.org/explained-fugitive-methane-emissions-from-natural-gas-production
[4] https://www.wri.org/blog/2013/04/close-look-fugitive-methane-emissions-natural-gas