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On January 6, Ohio Gov. Mike DeWine signed legislation that legally defined natural gas as a source of "green energy."

In a January 10 opinion piece U.S. representative Troy Baldwin (of Ohio) argues the case that natural gas is green, including this statement (emphasis added):

In Ohio, natural gas has already reduced carbon emissions from power generation by 38 percent. Further, increased production and usage in the United States of this green energy is key to helping lower emissions and to reaching emission reduction goals.

Is this a true statement?

The words "38 percent" are linked in the article to this page from the U.S. Energy Information Agency, which is just a list of data tables showing energy-related CO2 emissions by state. The data starts in 1970, so that would seem to be the starting year for the supposed 38% reduction.

LShaver
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  • Kind of like saying Jeffrey Dahmer is a good guy since he didn't kill nearly as many people as Timothy McVeigh. – user2199767 Jan 24 '23 at 19:07

3 Answers3

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From the linked tables, Ohio's carbon production fell from a high of 296.5 million metric tons in 2013 with regard to energy production to 185.6 million metric tons in 2020. That's a 37.4% reduction, which is close enough to 38% to make the claim true.

The issue with this claim is that compared to coal, natural gas is quite "green". Coal is mostly carbon while natural gas is mostly hydrogen (by atomic count). However, compared to solar or wind or nuclear power, natural gas is not anywhere close to "green".

Ohio used to use a lot of coal-powered electrical generation plants, many of which are no longer economically viable, so it was not all that hard to reduce carbon emissions by 38 percent by switching from coal to natural gas.

David Hammen
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    Also worth noting that the claim appears to address only CO2 emissions. Unfortunately, methane is far more potent as a greenhouse gas than carbon dioxide, and the expanded use of natural gas has led to much more leakage from pipelines and other facilities. – Mark Jan 18 '23 at 17:42
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    Can you attribute all of that 37.4% reduction to natural gas? Shouldn't it be attributed to solar, wind, hydro, nuclear, etc, if generation from those sources increased over the same time period? – LShaver Jan 18 '23 at 18:23
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    @LShaver From [this site](https://www.eia.gov/state/analysis.php?sid=OH), "Renewable energy resources supplied about 4% of Ohio's total in-state electricity generation in 2021." So yes, renewables did provide some of that drop, but not much. The vast majority of that reduction was from switching from coal (which had become not viable, economically) to natural gas. – David Hammen Jan 18 '23 at 20:53
  • @Mazura How so? Without regulatory costs, coal is significantly cheaper than natural gas. Particularly since the invasion in Ukraine. Particularly in Europe. – user71659 Jan 19 '23 at 05:35
  • @Mazura it is not a matter of how much effort was put into it, but a matter of emitting less and less CO2. Any way to do it is to be celebrated, more so if it is economically sound. – m e Jan 19 '23 at 08:50
  • @Mark While methane is a more potent greenhouse gas than carbon-dioxide, it also has a far lower lingering time in the atmosphere (decades vs. centuries). So while methane does more short-term damage to the climate, CO2 does more long-term damage. – Philipp Jan 19 '23 at 09:30
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    @Philipp Methane decomposes into CO2, so it does double damage, first as methane (which is a very potent greenhouse gas) and later as CO2. – David Hammen Jan 19 '23 at 11:30
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    @user71659 The question is about Ohio, not Europe. Fracking has made natural gas much cheaper than coal in the US. Mining gas is easy (given fracking) while mining coal is getting ever more difficult. Transportation costs are essentially non-existent after the natural gas pipeline has been built while transportation costs for coal are an ongoing expense. Maintenance costs for natural gas power plants are much lower than they are for coal. Add to that the anticipation coal will be taxed heavily, and its not surprising that coal-based power plants are being shuttered or converted to natural gas. – David Hammen Jan 19 '23 at 13:33
  • @Mazura see the comment https://skeptics.stackexchange.com/questions/54290/has-natural-gas-reduced-carbon-emissions-from-power-generation-by-38-in-ohio#comment264746_54291 . *Fracking has made natural gas much cheaper*. Then explore the reasons why fracking is so cheap. You may have some market-nasty surprise ( https://nexusmedianews.com/the-fed-could-rescue-fossil-fuel-firms-that-were-already-in-a-tailspin-336adbede97/ for an overview, not the best source I admit) – EarlGrey Jan 19 '23 at 15:15
  • Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/142214/discussion-on-answer-by-david-hammen-has-natural-gas-reduced-carbon-emissions-f). – tim Jan 20 '23 at 16:32
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    if these numbers don't include methane leaks, the claim is false, isn't it? – njzk2 Jan 20 '23 at 19:20
  • You added the detail in your comment but I think it needs to be clear in the answer that renewables have had minimal contribution to the reduction in emissions. Another factor which someone else pointed out -- has total load gone down? i.e. is it a 38% reduction in gross annual emissions, or per kWh? – LShaver Jan 21 '23 at 16:49
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No, this claim is misleading, bordering on false.

As identified in the methodology section of the article you linked, "The term energy-related CO2 emissions, as used in these tables, refers to emissions released at the location where fossil fuels are consumed."

Looking only at emissions released at the location where fossil fuels are consumed, there was close to a 38% reduction in emissions - probably closer to 35% noting 37.4% was the actual figure, and some of that was from renewables.

However, when analysing emissions, it is important to look at all emissions associated with an activity, not just those that occur in the same location as the consumption. All fossil fuels have fugitive emissions, which occur during extraction and transportation of the fossil fuel to the point it will be consumed.

Natural gas fugitive emissions are vastly higher than coal emissions - it's easier for a gas to escape than a solid. The difference in emissions intensity between the two fuels is much smaller than you might think, when fugitives are accounted for.

Estimates for fugitive emissions vary significantly.

According to this explainer, natural gas ceases to be a cleaner fuel than coal once fugitive emissions hit 3.2%, while studies generally identify leakage rates somewhere between 0.6 and 4%.

As a point of interest, the reason that a small amount of fugitive gas can have such a huge impact on emissions is not because you get less gas to burn at the end, it's the unburnt gas has much higher global warming potential than gas that has been used for something.

Scott
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    The linked tables show CO2-equivalents, which includes methane releases multiplied by a factor of about 25 to reflect that methane is a much more potent greenhouse gas than is CO2. Also note that burning coal releases some methane and also some NO2, also a potent greenhouse gas. Those are factored in. Burning natural gas also releases some methane and produces NO2, and those are factored in as well. Whether the reported 38% reduction is real and whether it's good enough (it isn't) are two different things. The question asks if that reported amount is real. – David Hammen Jan 20 '23 at 10:57
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    The claim pertains to power generation. Fugitive releases (Baltic Sea "accidents" notwithstanding) are generally due to the vast spiderweb of supply pipes to almost every home and business on the continent, not the very fat pipes from fields to large generating plants. – Harper - Reinstate Monica Jan 20 '23 at 19:10
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    Can you provide a source confirming that the EIA data (the source) does *not* account for fugitive emissions? As I recall, the EPA tracks this but may be undercounting. – LShaver Jan 21 '23 at 16:50
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    @LShaver - added the link. It’s the same site as that in the question but clicking on the methodology sub page – Scott Jan 21 '23 at 19:18
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    @Harper-ReinstateMonica - there’s fugitive emission in gas extraction, as well as transport. You can’t attribute it all to small consumers – Scott Jan 21 '23 at 19:24
  • @Scott I'm not saying "all" but certainly a great deal. Manufacturing can be regulated and the very few miles of big lines to power plants are inspected and maintaiained. The absolutely overwhelming mileage is the smaller distribution lines to (and within) structures, which is quite old and impracticable to inspect. Very little can be done about modest leaks there, except shut it down. – Harper - Reinstate Monica Jan 21 '23 at 22:20
  • @Harper-ReinstateMonica - Have you got a source for that? I was under the impression that extraction was the lion's share and that transmission (inclusive of both the large pipes and small pipes) was a minority. My udnerstanding is backed by sites like https://www.climate-chance.org/wp-content/uploads/2019/03/new-fugitive-emissions-a-blind-spot-in-the-fight-against-climate-change.pdf which concludes (with little detail) The available information suggests that the extraction and, to a lesser extent the processing and transportation, of fossil fuels is the main source of fugitive emissions. – Scott Jan 23 '23 at 02:23
  • @Scott I wasn't really thinking about production honestly. My line of thinking is that in-town distribution leaks *alone* are enough to threaten any environmental gains of using gas at home instead of at the power plant. I don't take the view that minority impacts don't matter. I might if I lived in a major container-ship port and the government wanted me to smog my car, though. – Harper - Reinstate Monica Jan 23 '23 at 03:18
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Their number seems ... low, actually.

Or they're underperforming.

Coal creates 211 pounds of CO2 per "million BTU", or 21.1 pounds per US therm.
Natural gas creates 117 pounds of CO2 per "million BTU", or 11.7 pound/therm.
Reducing from 211 to 117 is a 46% reduction.

Thus it is accurate to say (all else being equal) that switching from coal to natural gas fuel produces a 46% reduction in CO2. But as always, it's more complicated than that.

  • Coal requires more pre-processing and handling.
  • Coal can't be pipelined so it must move by rail (in practical terms they must use fair percentages of Wyoming coal, which doesn't ship). Those trains are all diesel - no electric freight in the USA except a few captive mine operations (one in Ohio actually).
  • Coal can't be run in gas turbines - natural gas can. And that matters because turbines allow combined-cycle operation, where the furnace itself makes shaft power, and the furnace's (waste) heat then feeds a boiler in the conventional way. A combined-cycle plant is about 50% more efficient than straight thermal. It's not uncommon for old coal boiler plants to have their heat source replaced with several gas turbines.

All these factors only further enhance gas's carbon performance compared to coal.

But also, Ohio has not been idle with wind and solar projects, so those too are pulling down their carbon numbers as well.

These factors combine to make Ohio's claim of 38% efficiency by using gas ... if anything, underperforming what ought to be practicable just within gas generation, nevermind the growing wind and solar sectors.

However, their thesis is misleading.

They're trying to say "we are 38% less black, therefore we are green" and that is of course balderdash.

A 38% reduction is only attractive if it's the least bad option available. And it's simply not.

Harper - Reinstate Monica
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  • "Least bad" by what metrics? Wind and solar may not produce CO2 directly as part of the electricity generation process, but between 1) the well-documented problems in manufacturing them, 2) their inability to run continuously, and (for wind at least) 3) the severe wear-and-tear experienced that shortens generators' lives, "greener" energy isn't doing a particularly good job of living up to the hype. – Mason Wheeler Jan 21 '23 at 02:28
  • @MasonWheeler It's the "least bad" amongst alternatives that use fossil fuels. Wind and solar advocates would strongly disagree with the rest of your comment, particularly your "isn't doing a particularly good job of living up to the hype" ending. – David Hammen Jan 21 '23 at 13:40
  • @DavidHammen Yes, but given wind and solar advocates' track record of fighting against hydroelectric and nuclear power, both of which do not use fossil fuels and also lack the three drawbacks I mentioned above, it doesn't particularly feel like "back the best power choices" are at the top of their agenda. – Mason Wheeler Jan 21 '23 at 13:49
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    @MasonWheeler You may have misread the end remark. Harper - Reinstate Monica explicitly wrote "**if** it's the *least bad option available*. And it's simply not." (I emphasized the **if**; Harper did not.) Compared to coal, natural gas is a better alternative. It pollutes less and it's more economical. But it is not the *least bad option available*. – David Hammen Jan 21 '23 at 14:33
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    @MasonWheeler Hydro and nuclear have their own drawbacks. People are foreseeing significant problems with hydro given the extended drought in the western US. It's not a particularly pretty picture, and climate change caused by CO2 emissions is making the picture even less pretty. Nuclear power has always had a problem with regard to what to do with the radioactive waste, and building a nuclear power plant is anything but cheap. That said, people who protest that "nuclear power = nuclear bombs" are idiots. There are idiots across the political spectrum. The best thing to do is to ignore them. – David Hammen Jan 21 '23 at 14:47
  • @DavidHammen Safe, long-term nuclear waste disposal is actually a trivial problem. It's not particularly difficult at all with today's technology; the "insurmountable" difficulties you've heard of are almost entirely FUD spread by activists. Likewise, it's not *particularly* expensive to build a nuclear plant; the massive costs come from insane layers upon layers of safety over-engineering regulations forced upon them by anti-nuclear activists spreading fear. (Remember, the Three Mile Island accident released less radioactivity than a single coal-burning plant operating for a year.) – Mason Wheeler Jan 21 '23 at 15:19
  • @MasonWheeler The FUD regarding nuclear waste disposal in Yucca Mountain (arguably the best site in the country) was a joint effort between Nevada Republicans and Democrats. Keep in mind that Nevada was a red state at the time. It wasn't "left wing activists". – David Hammen Jan 21 '23 at 15:42
  • @DavidHammen I didn't say anything about "left wing activists" or local opposition to Yucca Mountain. Please don't try to rebut points I never made. – Mason Wheeler Jan 21 '23 at 16:02
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    @MasonWheeler nuclear waste disposal may be a trivial problem from a technical standpoint, but it is clearly not from a political and economic standpoint, meaning that on balance, *it's not a trivial problem*. – LShaver Jan 21 '23 at 16:53
  • You may need a bullet point addressing difference in efficiency of coal vs natural gas plants -- those EIA numbers you cite are for heat content of the fuels -- how many of those therms actually become kWh on the other side? – LShaver Jan 21 '23 at 16:54
  • @LShaver there's not a lot of difference there. Combined-cycle is really the game changer. Coal plants can do stuff with supercritical heating, but it doesn't come anywhere close to the efficiency of combined-cycle. The hard part isn't turning therms into steam pressure, it's turning steam pressure into electricity and that doesn't care what the fuel was. – Harper - Reinstate Monica Jan 21 '23 at 22:12
  • I'm really just curious what the numbers are: for a ton of coal or a therm of gas, what percent of the input heat energy becomes electric energy? – LShaver Jan 22 '23 at 02:07
  • @LShaver There is a game. You can't win the game. You can't even break even. Everyone must play the game. (Those are the four laws of thermodynamics.) Using steam pressure, it doesn't matter how you play the game. You lose, big time. Using a gas turbine, you also lose, just not as badly. – David Hammen Jan 22 '23 at 08:52
  • @LShaver Coal power plants typically operate at the 33% thermal efficiency level. They're aiming for 40%. See https://www.energy.gov/fecm/transformative-power-systems. Combined cycle gas turbines typically operate at the 45% to 57% thermal efficiency level. They're aiming for 60%. See https://www.sciencedirect.com/topics/engineering/natural-gas-combined-cycle. Even the worst gas turbine outperforms the best coal plant with regard to converting chemical potential energy into electricity. – David Hammen Jan 22 '23 at 09:14