Fossil fuels

Fossil fuels include coal, oil, and natural gas. They occur naturally in the Earth, and can be burned for energy. They currently provide over 80% of the world's energy, but at a heavy environmental cost.

Terminology

• Natural gas is sometimes referred to as just gas. Not to be confused with gasoline.
• Crude oil is also known as petroleum, and it can be refined into oil products such as gasoline and diesel.

Usage as an energy source

Climate change

Major problem

Burning fossil fuels is the main cause of climate change, due to the CO₂ it releases into the atmosphere.

For the same amount of energy,

• coal releases about twice as much CO₂ as natural gas
• oil is somewhere in between.

See exact numbersSee exact numbers

These numbers might be needed for physics or engineering. Greenhouse gas emissions (CO_2eq) per unit of energy, for each fuel.

coal.ghg_by_energy

95.35 kg / million btu

CO2 emissions of burning coal

https://www.eia.gov/environment/emissions/co2_vol_mass.php

gasoline.ghg_by_energy

71.30 kg / million btu

CO2 emissions of burning gasoline

https://www.eia.gov/environment/emissions/co2_vol_mass.php

natural_gas.ghg_by_energy

53.07 kg / million btu

CO2 emissions of burning natural gas

Does not include the fugitive methane emissions from unburned fuel. Those vary by how the gas is burned.

https://www.eia.gov/environment/emissions/co2_vol_mass.php

usa.natural_gas.fugitive_ghg

176.1 million tonnes / year

Greenhouse gas CO2eq of fugitive methane leaks from all natural gas infrastructure in the USA

Environmental Protection Agency (EPA)
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014
2016 Complete Report (PDF)
Using data from 2014

usa.natural_gas.energy

27.9 quadrillion btu / year

U.S. energy consumption from natural gas combustion only

Environmental Protection Agency (EPA)
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014
2016 Complete Report (PDF)
Datapoint was found on page 115, from pie chart and line graph, using data from 2014

natural_gas.fugitive_ghg_by_energy

usa.natural_gas.fugitive_ghg / usa.natural_gas.energy

Fugitive emissions (CO2eq) of natural gas, per unit energy

Average based on US datapoints.

Coal: coal.ghg_by_energy kg / million btu (calculation loading)

Oil (gasoline is the most popular fuel obtained from crude oil): gasoline.ghg_by_energy kg / million btu (calculation loading)

Natural gas, which also has fugitive emissions(...)( Natural gas is mostly methane (CH₄) which is also a greenhouse gas. So when any unburned fuel leaks into the atmosphere (gas leaks), it also contributes to climate change too. ) taken into account here: natural_gas.ghg_by_energy + natural_gas.fugitive_ghg_by_energy kg / million btu (calculation loading)

Other pollution

Sometimes manageable

Burning fossil fuels releases more than just CO₂.

• Exhaust from cars and trucks
• Exhaust from coal power plants

These contain particles that are harmful to people and ecosystems.^{[ELABORATION needed]}

Mitigation

• Cars and trucks already have catalytic converters that eliminate some of this pollution - but not all of it.
• For coal power plants, newer technologies could avoid most of this pollution (but still not the CO₂ that causes climate change).

Scarcity

Eventual problem

Oil reserves are expected to run out in less than a century, by most estimates.^{[QUANTIFICATION needed]} Coal and natural gas are similar. Fossil fuels are not considered renewable(...)( despite being fossilized organic matter that was originally dead plants & animals ), because existing oil reserves took millions of years to form.

Globally, per person, there is about 31 tonnes of oil (recoverable) somewhere in the Earth. oil.reserves(tonnes per capita)(world.population). Average production is about 1.5 kg/day per person oil.production(lbs/day per capita)(world.population). Rich countries consume a lot more, poor countries use a lot less.

Non-energy usage

Fossil fuels are also used in making plastic, most of which is disposable. Other uses include making thousands of different chemicals, but together they add up to only a small fraction of fossil fuel consumption. ^{[QUANTIFICATION needed]}