Some fossil fuels are cleaner and emit less greenhouse gases than others.
In this guide, we look at which fossil fuels emit the most CO2 globally, and also in the two (currently) biggest emitting countries – China, and the United States.
Summary – Fossil Fuel That Emits The Most CO2 & Greenhouse Gases
In simplistic terms, coal is the fossil fuel that emits the most CO2 overall, both in total, and on a pro rata basis
[However, this can vary country by country, and year to year. It’s also expected in the future as more countries move to renewables that emissions from fossil fuels will change]
Globally, in terms of total tonnes of CO2 emissions, coal followed by oil emit the most greenhouse gases right now
In China, coal emits the most total tonnes of CO2 emissions by far right now
In the United States, oil emits the most total tonnes of CO2 emissions, followed by gas and coal
This emphasizes the energy splits between different countries
For electricity production (when measuring CO2 emitted per kilowatt hour produced) – one estimate indicates that coal releases the most CO2 at 2.2 pounds, followed by petroleum releasing 2.0 pounds, and natural gas behind that at 0.9 pounds of CO2 per kilowatt-hour
For transport – considering only tailpipe emissions (where over 80% of the emissions take place), natural gas also emits 15 to 20 percent less heat-trapping gases than gasoline when burned in today’s typical vehicle
So, it appears natural gas can be the cleanest of the three main fossil fuels – coal, oil and natural gas
Having said that, you also have to consider the total life cycle value a fossil fuel when considering emissions. For example, natural gas involves the leakage of methane at the drilling and extraction stage, which should be accounted for. Including emissions only from the fossil fuel burning stage presents an inaccurate picture of true emissions
Variables in general when calculating emissions from fossil fuels can include leakage rate, the global warming potential of different greenhouse gases, the energy conversion efficiency, and other factors.
We also put together this guide we talks about GHG emissions from different energy sources in general
Most Global CO2 Emissions By Fuel Source
Globally, annual per year CO2 emissions by fuel source, measured in billions of tonnes per year, in 2013, were:
- Solid Fuel (Coal) – 15.15 (Bt)
- Liquid (Oil) – 11.79
- Gas (Natural Gas) – 6.62
- Cement Production – 2.03
- Gas Flaring – 249.36 (Millions of tonnes)
CO2 Emissions In China By Fuel Source
China, has had the world’s largest carbon footprint since 2004 and was responsible for 27.6 percent of global carbon dioxide emissions in 2017.
China had 10.2 Gigatonnes of C02 Emissions in 2016 (29.2% of global C02 emissions). The breakdown by fuel source was:
- Coal – 7.17Gt C02
- Oil – 1.38Gt C02
- Gas – 0.395Gt C02
- Cement – 1.2Gt C02
- Gas Flaring – 0Gt C02
Roughly 70 percent of China’s CO2 emissions – which is more than those from all European, African, and Latin American countries combined – results from this heavy dependence on coal. An additional 14 percent of its CO2 emissions come from oil.
CO2 Emissions In The United States By Fuel Source
The United states had of 5.31 Gt of C02 Emissions in 2016 (15.3% of global C02 emissions). The breakdown by fuel source was:
- Coal – 1.38Gt C02
- Oil – 2.31Gt C02
- Gas – 1.53Gt C02
- Cement – 0.0407Gt C02
- Gas Flaring – 0.0459Gt C02
In the US, oil is the main source of CO2 emissions (43.5 percent), followed by natural gas (28.7 percent).
CO2 Emissions In Japan By Fuel Source
- Japan leans on coal for a quarter of its generated electricity, it only constitutes 38.2 percent of Japan’s CO2 emissions – an almost even split with oil, which accounts for 37.3 percent
Coal vs Natural Gas vs Oil – Emissions From Combustion, & Total Life Cycle Of Greenhouse Gases
Natural gas appears to be the cleanest of the three main fossil fuels.
But, you also have to allow for/include emissions at the extraction and mining stage to get a real picture of true emissions.
- Natural gas is a fossil fuel, though the global warming emissions from its combustion are much lower than those from coal or oil
- Natural gas emits 50 to 60 percent less carbon dioxide (CO2) when combusted in a new, efficient natural gas power plant compared with emissions from a typical new coal plant.
- Considering only tailpipe emissions, natural gas also emits 15 to 20 percent less heat-trapping gases than gasoline when burned in today’s typical vehicle
- Having said this, with natural gas, the drilling and extraction of natural gas from wells and its transportation in pipelines results in the leakage of methane … Preliminary studies and field measurements show that these so-called “fugitive” methane emissions range from 1 to 9 percent of total life cycle emissions
- Whether natural gas has lower life cycle greenhouse gas emissions than coal and oil depends on the assumed leakage rate, the global warming potential of methane over different time frames, the energy conversion efficiency, and other factors
- Natural gas emits 50 to 60 percent less carbon during the combustion process [than coa]