How much carbon dioxide is produced when different fuels are burned?

"Different fuels emit different amounts of carbon dioxide (CO2) in relation to the energy they produce when burned. To analyze emissions across fuels, compare the amount of CO2 emitted per unit of energy output or heat content.

Pounds of CO2 emitted per million British thermal units (Btu) of energy for various fuels:

Coal (anthracite) 228.6
Coal (bituminous) 205.7
Coal (lignite) 215.4
Coal (subbituminous) 214.3
Diesel fuel and heating oil 161.3
Gasoline (without ethanol) 157.2
Propane 139.0
Natural gas 117.0

The amount of CO2 produced when a fuel is burned is a function of the carbon content of the fuel. The heat content or the amount of energy produced when a fuel is burned is mainly determined by the carbon (C) and hydrogen (H) content of the fuel. Heat is produced when C and H combine with oxygen (O) during combustion. Natural gas is primarily methane (CH4), which has a higher energy content relative to other fuels, and thus, it has a relatively lower CO2-to-energy content. Water and various elements, such as sulfur and non-combustible elements in some fuels reduce their heating values and increase their CO2-to-heat contents."

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Does this include other production and processing emissions? Or just at the point of burn?

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This just at the point of burn.

Other production and processing emissions prior to burning are not included.

The burning of fossil fuels for conversion to useful energy like heating a house, heating water, or cooking will is much less than 100%. Much of the heat is lost to the venting required to remove the toxic gases in burning.

Coal fired power plants efficencies are in the 30% to 45% range
Combined cycle nat gas fired power plants are in range of 50% to 65% range

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They left out burning wood for energy. The emission factor for wood is almost 25% higher than coal.

Laganière et al.
Range and uncertainties in estimating delays in greenhouse gas mitigation potential of forest bioenergy sourced from Canadian forests
https://onlinelibrary.wiley.com/doi/10.1111/gcbb.12327
DB2

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Condensing natural gas water heaters are 90+% efficient. Space heating with gas can be around 80% efficient.

Definitely well under 100%, but light years ahead of things like vehicles, which are under 50% efficient. (Diesels can get close to that, gasoline tops out in the mid 30’s percent efficient.)

—Peter

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This old study does not discuss the whole range of biofuels of which wood is only a subset. Biofuels are renewable.

Agree about efficencies. But need to also consider the pollutants other than CO2 that hurt humans.

Burning wood to generate electricity produces more carbon dioxide per BTU than coal. It may or may not be ‘renewable’.

DB2

Not my problem that Canada wants to sell its old growth wood slash and unusable parts (branches, leaves, bark and sawdust) for making pellets for burning. This is still renewable subset of biofuels.

Where do you get this information? Please provide your source.

From the Laganiere paper linked upthread:
" For coal, oil, and natural gas combustion, we used the following emission factors: 90.6, 71.1, and 50.3 kg CO2eq GJ−1, respectively. For wood biomass, we used the default IPCC emission factor of 112.0 kg CO2eq GJ−1."

112/90.6 = 1.24

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In the longer term wood biomass is better than fossil fuels for reducing CO2 in the atmosphere.

From the Laganiere paper linked upthread:

Overall, our results are coherent with the perspective of Haberl et al . (2012) on C emission reduction by bioenergy.

Short- to medium-term atmospheric benefits (<50 years C parity time) must involve the use of ‘additional biomass’, defined as biomass from additional vegetation growth or biomass that would decay rapidly if not used for bioenergy. Such parity times are possible in some cases under salvaged tree scenarios, but more likely under specific conditions involving important gains in forest productivity (silviculture) under either green tree or salvage tree scenarios.

CO2 emission factors for biofuels might even exceed those for fossil diesel combustion due to large-scale land clearing related to growing biomass.

DB2

Not sure if this qualifies but Ireland had to outlaw peat fires. Peat after ages of time turns into coal.

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In a way, peat is low-grade lignite.

DB2

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I guess they don’t use peat smoke on malted barley to make Irish whiskey in the same way the Scots use that smoke in making scotch whisky. Or maybe the Irish distillers have some kind of exception to the law. Such a ban would not go over well with the distillers in Scotland.

  • Pete
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The Irish until more recently did not have central heat. The peat fires in the home were outlawed. That was most of the burning.

If you are talking gaining the heat of biomass with piping through it then I get you. Trinity college separately was putting in a deep ground system to tap into the earth’s mantel for energy. Literally the process was happening in the center of the campus.

I thought it was to protect peat bogs.

Might have been both. It is not an either/or. Dublin lost that smell that characterized it forever. I miss it. It was distinctive. Talk about air pollution though.

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