Natural gas is a fossil fuel, although its global warming emissions are substantially lower than those from coal or oil combustion. When combusted in a modern, efficient natural gas power plant, natural gas produces 50 to 60 percent less carbon dioxide (CO2) than emissions from a typical new coal plant [1].
Why does natural gas emit fewer CO2 emissions than coal?
In relation to the energy they create when burned, different fuels emit varied amounts of carbon dioxide (CO2). Compare the quantity of CO2 emitted per unit of energy output or heat content to compare emissions across fuels. CO2 emissions coefficients per unit of volume or mass and per million British thermal units are published by the US Energy Information Administration.
When a fuel is burned, the amount of CO2 created is a function of the carbon content of the fuel. The carbon (C) and hydrogen (H) content of a fuel determine its heat content, or the quantity of energy released when it is burned. When carbon (C) and hydrogen (H) combine with oxygen (O) during combustion, heat is created. Natural gas is mostly composed of methane (CH4), which has a larger energy content than other fuels and consequently a lower CO2-to-energy ratio. Water and different components in some fuels, such as sulfur and noncombustible elements, lower their heating values and raise their CO2-to-heat content.
For further information, go to:
What are the emissions factors for greenhouse gases and air pollutants for fuels and electricity?
Other FAQs about Environment
- What is the difference between short and metric tons?
- Is ozone classified as a greenhouse gas?
- How much of the carbon dioxide produced in the United States is due to power generation?
- What are the United States’ and the world’s energy-related carbon dioxide emissions from fossil fuels?
- What exactly are greenhouse gases, and how do they effect the environment?
- Why are carbon dioxide emissions heavier than the fuel they replaced?
- Does the EIA provide state-by-state estimates or projections for energy output, consumption, and prices?
- When different fuels are burned, how much carbon dioxide is produced?
- How much CO2 is produced per kilowatthour of electricity generated in the United States?
- How much carbon dioxide is created by gasoline and diesel fuel consumption in the United States?
- What are the sources and sectors of carbon dioxide emissions in the US energy sector?
Natural gas or coal produces more CO2.
Natural gas, coal, and diesel all produce varying levels of carbon dioxide. Natural gas emits nearly half as much CO2 as coal, according to the US Energy Information Administration. When coal is burned, different varieties of coal produce varied amounts of CO2.
For various fuels, pounds of CO2 emitted per million British thermal units (Btu) of energy
When compared to fuel, natural gas emits less carbon dioxide when burned. When only tailpipe emissions are considered, natural gas is 15-20% cleaner than gasoline when used.
Is natural gas less CO2 emitting than coal?
When natural gas is burned for energy, it produces fewer air pollutants and carbon dioxide (CO2) than when coal or petroleum products are burned to produce the same amount of energy. Natural gas emits about 117 pounds of CO2 per million British thermal units (MMBtu), compared to more than 200 pounds per MMBtu from coal and more than 160 pounds per MMBtu from distillate fuel oil. Natural gas’s clean-burning attributes have contributed to greater natural gas use in the United States for electricity generation and as a transportation fuel for fleet cars.
Why do people prefer natural gas to coal?
Title:
‘And as the world consumes more energy,’ a globe with cartoon lightning bolts in the background says.
As hands enter the picture from the bottom, the phrase ‘we need to offer electricity’ appears.
‘that is available and environmentally sustainable’ appears in the center of the page, surrounded by pipes, plants, and blue flames.
When the phrase ‘producing one-tenth of the air pollutants as coal when burned to generate energy’ is displayed, a lightbulb is added to the end of the phrase.
On a natural gas facility, the word ‘natural gas’ is displayed down the side of cooling towers against a background of syk and trees, with pipelines at the bottom.
On the right, the text ‘to our cities and towns’ is displayed. In the background, buildings and residences rise up.
‘in conjunction with natural gas’
‘Nearly global reach’ appears above an ocean with floating LNG tankers. On the side of the main, largest tanker, it says ‘Natural Gas.’
‘Ensures that natural gas’ appears against a backdrop of pipelines, with a modest map of the United States ‘Gas’ accompanied by a blue flame.
‘Can play a crucial role in the energy mix,’ displays a picture of a Key with the word ‘Key’ written over it.
‘It doesn’t matter where you reside.’ The shot pulls back to reveal a globe covered in pipes. The phrases appear on the globe, which is surrounded by LNG tankers.
Over a blue sky and grassy landscape, the message ‘Renewable energy is critical to our future’ appears. To the right, solar panels and a bright sun, while to the left, wind turbines.
The words ‘when the wind blows and the sun shines’ are written in the center of the screen. The wind turbines cease whirling when a cloud passes in front of the sun.
‘Natural gas can keep our lives’ displays, Gas with a blue flame, and ‘our lives’ with hands on both sides.
The word ‘powered reliably’ is shown with a blue gas flame above it and arrows circling it.
What advantages does natural gas have over coal?
- Natural gas is the cleanest fossil fuel energy source accessible, albeit it is not as pure as solar or wind energy. According to the Florida Natural Gas Association, each residence that utilizes a tankless water heater instead of a heater fueled by another source keeps 3,000 pounds of carbon dioxide out of the atmosphere.
- When burned, natural gas emits roughly a third less carbon dioxide than coal and nearly half as much as oil. Natural gas produces little to no sulfur, making it more environmentally friendly and efficient than other fuels.
How much CO2 does natural gas produce?
In 2019, the United States had 120.9 million households (EIA 2020a). Each home used an average of 11,880 kWh of provided power. In 2019, total household consumption of natural gas, liquefied petroleum gas, and fuel oil was 5.23 quadrillion Btu, 0.46 quadrillion Btu, and 0.45 quadrillion Btu, respectively (EIA 2020a). This equates to 41,510 cubic feet of natural gas, 42 gallons of liquefied petroleum gas, and 27 gallons of fuel oil per family in the United States.
In 2019, the national average carbon dioxide output rate for generated energy was 884.2 lbs CO2 per megawatt-hour (EPA 2021), equating to around 953.7 lbs CO2 per megawatt-hour for delivered electricity (assuming 7.3 percent transmission and distribution losses) (EPA 2021; EIA 2020b).
1
Natural gas has an average carbon dioxide coefficient of 0.0551 kg CO2 per cubic foot (EIA 2019). The total amount of CO2 oxidized is 100 percent (IPCC 2006).
Distillate fuel oil has an average carbon dioxide coefficient of 431.87 kg CO2 per 42-gallon barrel (EPA 2021). The total amount of CO2 oxidized is 100 percent (IPCC 2006).
Liquefied petroleum gases have an average carbon dioxide coefficient of 235.7 kg CO2 per 42-gallon barrel (EPA 2021). The oxidized percentage is 100 percent (IPCC 2006).
Total CO2 emissions per home were calculated by converting total residential electricity, natural gas, distillate fuel oil, and liquefied petroleum gas consumption from various units to metric tons of CO2.
Calculation
Note that due to rounding, the results of the computations given in the equations below may not be correct.
1. Electricity: 11,880 kWh per home(1/(1-0.073)) = 884.2 lbs CO2 per megawatt-hour generated MWh produced vs. MWh delivered 1 metric ton/2,204.6 lb = 5.139 metric tons CO2/home = 1 MWh/1,000 kWh1 metric ton/2,204.6 lb = 1 metric ton/2,204.6 lb = 1 metric ton/2,204.6 l
2. Natural gas: per residence, 41,510 cubic feet
2.29 metric tons CO2/home = 0.0551 kg CO2/cubic foot/1,000 kg/metric ton
3. LPG (liquefied petroleum gas): 42 gallons per household
1/42 gallon/barrel
CO2/barrel: 235.7 kg
0.23 metric tons CO2/home = 1/1,000 kg/metric ton
4. Fuel oil consumption: 27 gallons per household
1/42 gallon/barrel
CO2/barrel: 431.87 kg
0.28 metric tons CO2/home = 1/1,000 kg/metric ton
5.139 metric tons CO2 for electricity + 2.29 metric tons CO2 for natural gas + 0.23 metric tons CO2 for liquid petroleum gas + 0.29 metric tons CO2 for fuel oil = 7.94 metric tons CO2 per residence per year.
Sources
- Environmental Impact Assessment (EIA) (2020a). Residential Sector Key Indicators and Consumption, Table A4 of the 2020 Annual Energy Outlook.
- Environmental Impact Assessment (EIA) (2020b). Table A8: Electricity Supply, Disposition, Prices, and Emissions in the 2020 Annual Energy Outlook.
- Environmental Impact Assessment (EIA) (2019). Table A4: Approximate Heat Content of Natural Gas for End-Use Sector Consumption, Monthly Energy Review November 2019. (PDF) (About PDF, 270 pages, 2.65 MB)
- Environmental Protection Agency (EPA) (2021). Greenhouse Gas Emissions and Sinks in the United States, 1990-2019. Tables A-47 and A-53 in Annex 2 (Methodology for Estimating CO2 Emissions from Fossil Fuel Combustion). Washington, DC: US Environmental Protection Agency. #430-R-20-002 (PDF) (US EPA) (96 pp, 2 MB, About PDF)
- Environmental Protection Agency (EPA) (2021). eGRID, yearly national emission factor for the United States, data for 2019. Washington, DC: US Environmental Protection Agency.
- IPCC (Intergovernmental Panel on Climate Change) (2006). The IPCC Guidelines for National Greenhouse Gas Inventories were published in 2006. 2nd Edition (Energy). Geneva, Switzerland: Intergovernmental Panel on Climate Change.
Which fuel emits the most CO2?
We already know that the world’s carbon budget is depleting at an alarming rate, but a new scientific assessment exposes just how grim the global carbon cycle really is.
According to the Global Carbon Project’s (GCP) 2013 study, carbon dioxide (CO2) emissions from burning fossil fuels and making cement have reached their greatest level in human history at precisely the time when emissions reductions are most needed.
The GCP is a collaborative effort between the International Geosphere-Biosphere Programme, the International Human Dimensions Programme on Global Environmental Change, the World Climate Research Programme, and Diversitas, with all datasets and modeling output described in peer-reviewed journals. The following are some of the highlights from the GCP summary:
What are the current global CO2 emissions levels and concentrations?
CO2 emissions related with burning fossil fuels and making cement increased by 2.1 percent in 2012, with a similar increase projected in 2013.
CO2 emissions from burning fossil fuels and manufacturing cement increased by 58 percent in 2012, compared to 1990 levels.
In 2012, the average global CO2 concentrations in the atmosphere were 392.5 parts per million (ppm). This is the most concentrated population in at least 800,000 years. Global atmospheric CO2 concentrations briefly exceeded 400 ppm earlier this year, but this was not mentioned in the GCP report.
In 2012, around 9.7 billion tonnes of carbon were released into the atmosphere as a result of burning fossil fuels and making cement. This is the same amount of carbon dioxide emitted by almost 10,000 coal-fired power units.
Between 1870 and 2013, approximately 390 billion tonnes of carbon were discharged into the atmosphere by burning fossil fuels and making cement.
Between 1870 and 2013, approximately 160 billion tonnes of carbon were emitted into the atmosphere as a result of land use change (e.g. deforestation).
Between 1870 and 2013, all human activities emitted approximately 550 billion tonnes of carbon into the atmosphere, with fossil fuels and cement accounting for more than two-thirds of all carbon emissions.
What fuels and sectors are creating the world’s emissions?
During the period 2003-2012, the average share of total CO2 emissions caused by human activities that were connected with deforestation and other land use changes was 8%. In fact, according to a new scientific study, the world loses the equivalent of 50 soccer fields of forest every minute of every day.
Oil accounted for 33% of all CO2 emissions from fossil fuel combustion and cement production in 2012.
Coal accounted for 43 percent of total CO2 emissions from fossil fuel combustion and cement production in 2012. Despite producing the greatest CO2 emissions of any fossil fuel, coal continues to be the world’s primary energy source.
Who is generating the world’s emissions?
In 2012, India’s per capita carbon emissions were 0.5 tonnes. In 2012, India accounted for 6% of world CO2 emissions from fossil fuels, and its emissions climbed 7.7% over 2011.
Carbon emissions per capita in China in 2012 were 1.9 tonnes. In 2012, China was responsible for 27% of worldwide CO2 emissions from fossil fuels, up 5.9% from 2011.
Carbon emissions per capita in the European Union in 2012 were 1.9 tonnes. In 2012, the EU accounted for 10% of worldwide CO2 emissions from fossil fuels, with emissions down 1.3 percent from 2011.
Carbon emissions per capita in the United States in 2012 were 4.4 tonnes. In 2012, the United States accounted for 14 percent of world CO2 emissions from fossil fuels, a drop of 3.7 percent from 2011.
How much global warming can these emissions cause?
While each of the figures in GCP’s 2013 report is significant in its own way, one in particular stands out: By 2100, the world will have warmed by 3.2-5.4 degrees Celsius above pre-industrial levels due to our cumulative carbon dioxide emissions. We fear increasingly deadly levels of forest fires, coral bleaching, sea level rise, and other significant impacts with each degree of temperature rise.
According to a recent report by the Intergovernmental Panel on Climate Change (IPCC), if we continue on our current carbon-intensive path, we will exhaust our carbon budget in around 30 years. Once again, we’re reminded that the window for reducing emissions is rapidly closing. It serves as a timely reminder of the high stakes for international negotiators at COP 19.
- GET MORE INFORMATION: Unrestricted coal use will break the world’s “carbon budget,” according to a WRI blog post.
How much CO2 does coal produce?
Carbon dioxide is the most well-known byproduct of coal (CO2). Burning coal produces an average of 208 pounds of CO2 per million BTUs released (see note below). Because a ton of coal has 20.025 million BTUs, it produces 4,172 pounds of CO2 when burned. One year of use of our 100-watt bulb produces 1,670 pounds of CO2.
But, hold for a second, how can 800 pounds of coal emit twice as much CO2? Another article from the EIA explains this in detail but, in short, it’s because the carbon atoms in coal are each combined with two atoms of oxygen from the air to form the CO2. In other words, the greater weight is due to material being pulled in for the air.
1670 pounds of CO2 would fill three 18-wheeler trucks at room temperature and pressure.
Is natural gas taking the place of coal?
Natural gas accounts for 40% of the electric generation portfolio, according to the US Energy Information Administration, whereas coal accounts for 19% and is declining. Natural gas has been displacing coal since it emits half as many pollutants when used in a power plant. Wind and sun account about 10% of the total, but their prospects are far brighter. Nuclear energy accounts for 19 percent of the country’s total electricity generation and 60 percent of its carbon-free generation.
