9 ms·
More than 100 coal-fired plants have been converted to natural gas since 2011
- melling 6y agoA little over 20% of US electricity is generated from coal. There are around 2400 coal power plants in the world. My understanding is that if we could turn off all the coal plants tomorrow we could actually significantly reduce greenhouse gas emissions. Would it buy us a significant amount of time if we accelerated the conversation to natural gas?
- abejfehr 6y agoI don't think natural gas is actually a carbon-neutral alternative to coal, my understanding is that methane leakage makes it almost as bad as coal in the long term. https://www.vox.com/energy-and-environment/2019/5/30/18643819/climate-change-natural-gas-middle-ground https://www.vox.com/energy-and-environment/2019/5/30/1864381...
- causality0 6y agoTrue, but it doesn't have the incredibly horrific non-carbon pollution problems of coal. The things almost every coal plant in the world does to nearby rivers would nauseate most people. Fly ash produced by coal plants releases one hundred times the radiation into the environment as a nuclear plant of the same capacity.
- avalys 6y agoThat’s only true because the amount of radiation released by a nuclear plant in normal operation is also negligible.
- willis936 6y agoThe actual number closer to 1,000 than 100. There is a lot of uranium and thorium in coal. Not all of it is captured when coal is burned. https://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/ https://www.scientificamerican.com/article/coal-ash-is-more-...
- makomk 6y ago"A lot" is relative. From what I can tell, coal ash contains about the same amount of uranium and thorium as granite and slightly more than ordinary soil. (Of course, it's less concentrated in the coal itself, which is largely carbon and hydrocarbons that gets burnt off.) The main reason coal power releases so much radiation compared to nuclear because there's a lot of coal burnt and normal operation of nuclear power plants also releases very little. What's more scary is the production of things like rare earth minerals - that quite heavily concentrates the uranium and thorium as part of the extraction process, producing large quantities of relatively radioactive mining waste.
- jweir 6y agoMethane breaks down much faster than carbon and methane leaks can be mitigated. You don’t have to have them.
- Nasrudith 6y agoIt breaks down into carbdon dioxide.
- marcosdumay 6y agoCoal leaks methane too. A while ago there were people here pointing that even more than natural gas; I'm not convinced, but both are on the same ballpark. Anyway, methane is a short term problem. It's CO2 that is long term.
- melling 6y agoI didn’t say it was carbon neutral. Coal adds much more CO2 to the atmosphere. At least twice as much? Rather than losing more time waiting for the perfect solution, a big step 10 years earlier might buy us additional time.
- fuoqi 6y agoA LOT of methane is released during coal mining as well, it's estimated that 9% of total global methane emissions can be attributed to it: https://www.epa.gov/cmop/frequent-questions#q6 https://www.epa.gov/cmop/frequent-questions#q6
- joe-collins 6y agoIt isn't neutral at all, it's merely less-intensive. Leakage is a problem with straightforward extant solutions, but well operators are poorly incentivized to implement those solutions—the loss is often too small to substantially impact their profit, and the leak is invisible (natural gas being colorless) so it's easy to turn a blind eye and not implement effective monitoring.
- iamthemonster 6y agoI'm not sure how we would implement any more effective monitoring of natural gas leakage. We have gas detectors all over the facility and personnel walk around with gas detectors on their coveralls. Flowmeters are generally not accurate to <1%. I would expect the only credible thing we can do is design it out, e.g. by running seal vents to flare rather than safe location, improving reliability, flareless operation etc. I imagine the majority of "leakage" must be unburnt hydrocarbon in flare and GT exhausts. But when you say "straightforward extant solutions" what are you referring to? In the industry, nobody particularly assesses "leakage" or really designs for minimising leakage per se.
- londons_explore 6y agoIt could be mandated that all facility pressures be below atmospheric pressure. Then all leaks would lead to air getting into the pipes rather than gas getting out. Clearly with that being the case, one needs much bigger more expensive pipes.
- treeman79 6y agoHad my lungs ruined by natural gas leaks. This solution sounds very scary.
- iamthemonster 6y agoThat would easily solve the problem, by making any gas processing facilities completely uneconomic to operate ;) I am quite interested in the idea of methane leakage though. There seems to be a growing consensus online that it exists and is significant, but within industry it is really not recognised.
- reitzensteinm 6y agoDon't you mean the short term? Methane being a very potent greenhouse gas but it breaks down with time.
- ekianjo 6y agoNatural gas is way cleaner than coal overall. It does not release particles that kill people over the long term either. It's a pretty clear cut between the two.
- lysp 6y agoIf you only compare the burning stage.
- toomuchtodo 6y agoWith the current cost of solar and wind, coal->natural gas conversions aren't a slam dunk for utilities or investor owned generators. > Coal power plants in the US have been retiring at an average clip of 10 gigawatts per year as the clean energy transition takes hold. That may sound impressive, but it’s not nearly quick enough, considering that climate change is already buffeting the Earth. The pace has to pick up quickly in order to avoid more catastrophe. That’s where a new thing called solar-for-coal swaps comes in. The “swap” part is a bit complicated, but if the idea catches hold it could speed up coal power plant retirements and skim more than 20 gigawatts right off the top. > In a new white paper, the clean energy group Energy Innovation has identified some low hanging coal fruit, in the form of 179 gigawatts that can’t compete on cost with solar any more. These coal units are still operating for various reasons even though solar saves money, but Energy Innovation has picked out a group of 22.5 gigawatts that could be rolled over in short order. https://cleantechnica.com/2020/08/09/solar-for-coal-swaps-could-turbocharge-clean-energy-revolution-cleantechnica-interview/ https://cleantechnica.com/2020/08/09/solar-for-coal-swaps-co...
- cagenut 6y ago> My understanding is that if we could turn off all the coal plants tomorrow we could actually significantly reduce greenhouse gas emissions. yes. in 2018 40% of all CO2 emissions were from coal: https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions#co2-emissions-by-fuel https://ourworldindata.org/co2-and-other-greenhouse-gas-emis... that graph is the simplest possible way to think about "dealing with climate change". Its a checklist: #1 coal. #2 oil. #3 gas. Gas has been a "transitional" fuel in the sense that its made the last decade less bad than it would have been, but given the timeline left* its already too late to build new gas infrastructure, assuming you intend to finance it with 30 year bonds. * per the ipcc in order to stay under 2C emissions need to hit zero somewhere between 2040 for rich/western countries and 2055 for the whole planet, and then be followed by negative emissions for the rest of the century
- hinkley 6y agoFrom the article, only 49 of 316 GW (16%) of coal capacity was replaced in eight years. This is Detroit and fuel efficiency all over again. Look how good we are doing dragging our feet! (Even though the results allow a lot of cool things).
- cwojno 6y agoNo, quite the opposite, actually. 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 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=Coal%20and%20Air%20Pollution,environmental%20and%20public%20health%20impacts 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.pdf https://www.eia.gov/outlooks/aeo/pdf/electricity_generation.... tl;dr: No. Burning gas is worse from a climate perspective.
- phonon 6y agoErrr, probably you should read it again? Natural gas has about half the CO2 emissions per unit of energy as coal. Maybe this[1] or this[2] is clearer. [1] https://www.eia.gov/environment/emissions/co2_vol_mass.php https://www.eia.gov/environment/emissions/co2_vol_mass.php [2] https://www.eia.gov/electricity/annual/html/epa_a_03.html https://www.eia.gov/electricity/annual/html/epa_a_03.html
- 6y ago
- gok 6y ago…but over 546 have been retired permanently source: https://www.eia.gov/todayinenergy/detail.php?id=40212 https://www.eia.gov/todayinenergy/detail.php?id=40212
- joe-collins 6y agoEven better news, really.
- mikece 6y agoAnd replaced with what? While coal is dirtier than natural gas the calorific value is far greater so you get a lot more heat and electricity per unit of combustion by-product. If these coal plants were replaced by gas-burners then emissions haven't been eliminated, only reduced. If we really want to ELIMINATE emissions we need to be looking at base-load sources that emit zero carbon such as nuclear.
- NineStarPoint 6y agoBased on https://www.eia.gov/energyexplained/us-energy-facts/ https://www.eia.gov/energyexplained/us-energy-facts/ So in 2011 we had: Coal at 19.66 quadrillion BTU Natural Gas at 24.95 quadrillion BTU Petroleum at 34.63 quadrillion BTU Nuclear at 8.27 quadrillion BTU Renewables at 9.20 quadrillion BTU In 2019 we had: Coal at 11.31 quadrillion BTU (-8) Natural Gas at 32.10 quadrillion BTU (+7) Petroleum at 36.72 quadrillion BTU (+2) Nuclear at 8.46 quadrillion BTU (+0.2) Renewables at 11.45 quadrillion BTU (+2) Basically we replaced the use of Coal with natural gas, and used Renewables to add on new capacity. Indeed not exactly a rosy picture of lowering our emissions. And what’s not captured here is that we dropped our fuel use drastically during the 2007-2009 financial crisis and only just recovered from that drop. But our Real PCE (Personal Consumption Expenditures) went up 30% in that same time frame. While it’s not a 1-1 correlation or anything, increased consumption without increased electricity use probably means we’ve just off-shored a lot of our usage to less developed countries in the last 13 years anyway.
- Retric 6y ago
- baybal2 6y agoRankine cycle natural gas plants are less efficient than Bryton cycle plants. Converted plans will always loose out to gas turbine plants.
- pfdietz 6y agoMore specifically, Brayton cycle with a Rankine bottoming cycle (combined cycle). Open cycle gas turbines are about as efficient as supercritical steam plants (but are much cheaper to build).
- baybal2 6y agoAn _average_ steam turbine plant is nowhere near as efficient as a big enough single cycle gas turbine. A top tier boiler plan of course may well be approaching a smaller/cheaper turbine.
- arkh 6y agoI "like" the use of the term natural to make it sound like gas powered plants are a good thing.
- tialaramex 6y agoHistorically it was common to make a useful "town gas" which could be used to make heat and light in homes or factories. Often "coal gas" was the town gas used, you make it by processing coal, so, unsurprisingly, the carbon emissions are worse than coal. When it was discovered that the planet has a whole bunch of natural methane we could harvest that's a natural gas you can use instead. It's cheaper, it burns cleaner, once you discover it there's nothing not to like... Coal gas is also poisonous and its density means it's inclined to lay in a room, so when e.g. Britons mostly cooked with coal gas ovens that's where you get the phrase "Put your head in the oven". The idea isn't that you could somehow suicide by cooking yourself, but instead that the poisonous gas will kill you. These days if you have a gas oven (they're rarer) and try this it won't work, the gas isn't poisonous and will escape from most spaces - although you might if you're unlucky manage to collect the right amount of methane somewhere to cause an explosion. The reduction in suicide from upgrading from town gas to natural gas is a success story and a model for other interventions. It showed very clearly that "displacement" isn't a big deal. People didn't go "Huh, my oven didn't kill me. Oh well I'll jump off a building". Thus, other interventions can be expected to be effective, such as anti-suicide fencing on bridges or platform screen doors at railway stations.
- jdeibele 6y agoMy house was built in 1914, which is fairly old for Portland. It's been heated by 5 different technologies: 1) Manufactured Gas, which I assume is the same as coal gas. The pipe for this is about 3 times as large as natual gas. 2) Wood chips (still a spot in the concrete floor where the "octopus" furnace (called because of the vents coming off it) sat. This was a byproduct of the timber industry. 3) Oil. The underground tank in the side yard was filled in. 4) Natural gas 5) Air heat pump powered by electricity (partially fed by solar panels) I'm not sure of the exact order but I think that's basically correct, as the development of trucks meant it was possible to drop off a big bunch of wood chips or later a tankful of oil. I've read that some towns are not allowing new natural gas connections because of pollution issues. With the explosion yesterday in Maryland and our problems keeping up infrastructure, it seems like a reasonable approach to me.
- LatteLazy 6y agoWhich is great, except that we're emitting vastly too much still and emissions are growing and it will soon be too late to avoid disaster.
- jjt-yn_t 6y agoGoing by the experience of being at a generating plant that did oil/gas > gas, another benefit is worker safety...