Coal is the most carbon-intensive fuel, releasing about 90 g CO2/MJ, while natural gas emits 25% less, or only about 68 g CO2/MJ; because in the US coal generated nearly half of all electricity in 2005 and only 30% by 2016, the country achieved a faster reduction of its CO2 emissions during that period than any other high-income economy, including Germany with its heavily subsidized PV and wind electricity generation.
