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cwojno | 5 years ago
Natural gas conversion mostly reduces particulates. The EIA data says natural gas produces more CO2/MkWh than coal:
Electricity generation CO2 emissions million kWh million metric tons million short tons pounds per kWh Coal 1,124,638 1,127 1,240 2.21 Natural gas 1,246,847 523 575 0.92 Petroleum 21,860 21 23 2.11
https://www.eia.gov/tools/faqs/faq.php?id=74&t=11
Ironically, particulates decrease insolation and actually slightly reduce warming (CO2's half life is a lot longer than particulates, so the "cooling" is short-lived and will go away when you stop burning coal, net warming, overall). Natural gas doesn't produce as many particulates, so I would expect that converting to natural gas would increase global warming in the short and long term compared to continue to burn coal.
It's far better to switch to solar/wind/geo/nuclear than natural gas in the long run, but there are health benefits to removing the coal particulates:
"Coal impacts: air pollution When coal is burned it releases a number of airborne toxins and pollutants. They include mercury, lead, sulfur dioxide, nitrogen oxides, particulates, and various other heavy metals. Health impacts can range from asthma and breathing difficulties, to brain damage, heart problems, cancer, neurological disorders, and premature death." https://www.ucsusa.org/resources/coal-power-impacts#:~:text=....
I presume that the primary driver of this conversion isn't the environment, but economics. The price of coal/kWh is more expensive than the volume of gas required to generate the same kWh. The Total system LCOE is usually the number people want to minimize. https://www.eia.gov/outlooks/aeo/pdf/electricity_generation....
tl;dr: No. Burning gas is worse from a climate perspective.
phonon|5 years ago
Maybe this[1] or this[2] is clearer.
[1] https://www.eia.gov/environment/emissions/co2_vol_mass.php
[2] https://www.eia.gov/electricity/annual/html/epa_a_03.html
brabel|5 years ago
That table says there's slightly more kWh generated from natural gas (1,246,847) than from coal (1,124,638). I assumed they read this wrongly and thought this was CO2 emissions per kWh.
The best number to read from that table is the last column, "CO2 emissions - pounds per kWh":
Natural Gas: 0.92
Coal: 2.21
So yeah, natural gas's CO2 emissions are much lower.
cwojno|5 years ago
jillesvangurp|5 years ago
Gas plants are much better from that point of view but still too expensive. Renewables are really killing it on the cost front and with viable energy storage solutions coming online even a role as peaker plants is not going to be a long term thing for gas plants.
Economics are also the reason nuclear is not happening. It's just too expensive and risky for operators to get involved in. When prices below 0.02$/kwh are becoming normal for new solar bids, that kind of puts the squeeze on everything else. Even gas. And there is no sign of this being a final price, this will likely dip well below 0.01$ at some point.
The only reason for investments like this is short term gains while production capacity for clean energy simply can't cover the whole market just yet. So converting coal plants makes sense to replace expensive capacity with slightly less expensive capacity while enough cheap capacity to replace it is short term just not there yet.
ravingraven|5 years ago
Solar and wind require gas plants as balance when the sun is not shining and the wind is not blowing. All other "infinite" energy sources such as coal or nuclear don't have enough dispatchability to perform solar/wind load following. Hydroelectric has a high dispatchability but is not infinite (the lake level gets too low and you have to wait for the next rain).
cwojno|5 years ago