Electricity sector is the largest contributor of greenhouse gases

The Electricity sector involves the generation, transmission, and distribution of electricity. Carbon dioxide (CO₂) makes up the vast majority of greenhouse gas emissions from the sector, but smaller amounts of methane (CH₄) and nitrous oxide (N₂O) are also emitted. These gases are released during the combustion of fossil fuels, such as coal, oil, and natural gas, to produce electricity. Less than 1% of greenhouse gas emissions from the sector come from sulfur hexafluoride (SF₆), an insulating chemical used in electricity transmission and distribution equipment.

Greenhouse Gas Emissions in the Electricity Sector by Fuel Source

Coal combustion is generally more carbon intensive than burning natural gas or petroleum for electricity. Although coal accounts for about 77% of CO₂emissions from the sector, it represents about 39% of the electricity generated in the United States. About 27% of electricity generated in 2014 was generated using natural gas, an increase relative to 2013. Petroleum accounts for approximately 1% of electricity generation. The remaining generation comes from nuclear (about 19%) and renewable sources (about 13%), which includes hydroelectricity, biomass, wind, and solar.^[1] These other sources usually release fewer greenhouse gas emissions than fossil fuel combustion, if any emissions at all.

Emissions and Trends

In 2014, the electricity sector was the largest source of U.S. greenhouse gas emissions, accounting for about 30% of the U.S. total. Greenhouse gas emissions from electricity have increased by about 12% since 1990 as electricity demand has grown and fossil fuels have remained the dominant source for generation.

Greenhouse Gas Emissions by Electricity End-Use

Electricity is consumed by other sectors–in homes, businesses, and factories. Therefore, it is possible to attribute the greenhouse gas emissions from electricity production to the sectors that use the electricity. Looking at greenhouse gas emissions by end-use sector can help us understand energy demand across sectors and changes in energy use over time.

When emissions from electricity are allocated to the end-use sector, industrial activities account for a much larger share of U.S. greenhouse gas emissions. Emissions from commercial and residential buildings also increase substantially when emissions from electricity are included, due to their relatively large share of electricity consumption (e.g., lighting and appliances).

Reducing Emissions from Electricity

There are a variety of opportunities to reduce greenhouse gas emissions associated with electricity generation, transmission, and distribution. The table shown below categorizes these opportunities and provides examples. For a more comprehensive list, see Chapter 7 of the Contribution of Working Group Read More…