US EIA: Natural Gas CO2 Emissions are Exceeding Coal Emissions
For the first time since 1972, energy-associated carbon dioxide (CO2) emissions from coal are dropping below natural gas CO2 emissions.
The US Energy Information Agency’s latest Short-Term Energy Outlook reports that energy-related CO2 emissions from natural gas are expected to be 10 percent higher than coal emissions for 2016.
This is a classic case of good news wrapped in bad.
Tirelessly documenting the long, slow slide into statistical irrelevance, the US EIA is finally reporting the decline of Old King Coal‘s reign of CO2 Terror. But the Dictator’s death is not a cause for celebration. Natural Gas has staged a coup.
Evaluating Carbon Emissions and Intensities
First, let’s unwrap the good news. The EIA states that, in general, US carbon intensity rates have been decreasing annually since 2005. Carbon intensity in energy terms represents the weight of CO2 emitted by a fuel type per unit of energy consumed, typically the British thermal unit (Btu). This is commonly expressed as CO2/Btu. A total carbon intensity rate reflects the relative consumption of each fuel type and each types’ relative carbon intensity.
Petroleum, at around 65 million metric tons of CO2 per quadrillion British thermal units (MMmtCO2/quad Btu), is more carbon intensive than natural gas and less intensive than coal. However, petroleum represents the larger responsibility for US energy-related carbon emissions due to its significantly higher consumption rate.
Petroleum processing is notoriously sloppy, too.
The carbon intensity of natural gas is around 52 MMmtCO2/quad Btu. Coal’s carbon intensity is nearly 95 MMmtCO2/Btu, or around 82 percent higher than natural gas. For this reason, even when annual consumption of natural gas and coal were roughly equal, as was the case in 2005, CO2 emissions from energy-related coal were around 84 percent higher than emissions from natural gas.
This scenario reversed in 2015. Both US coal and natural gas were measured at roughly 1.5 billion metric tons of energy-related CO2 emissions. Now, however, natural gas consumption is 81 percent higher than coal consumption.