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Replacing Coal with Gas or Renewables Saves Billions of Gallons of Water:
"While most attention has been focused on the climate and air quality benefits of switching from coal, this new study shows that the transition to natural gas—and even more so, to renewable energy sources—has resulted in saving billions of gallons of water," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.
[...] "For every megawatt of electricity produced using natural gas instead of coal, the amount of water withdrawn from local rivers and groundwater is reduced by 10,500 gallons, the equivalent of a 100-day water supply for a typical American household," said Andrew Kondash, a postdoctoral researcher at Duke, who led the study as part of his doctoral dissertation under Vengosh.
[...] If all coal-fired power plants are converted to natural gas, the annual water savings will reach 12,250 billion gallons—that's 260% of current annual U.S. industrial water use.
Although the magnitude of water use for coal mining and fracking is similar, cooling systems in natural gas power plants use much less water in general than those in coal plants. That can quickly add up to substantial savings, since 40% of all water use in the United States currently goes to cooling thermoelectric plants, Vengosh noted.
[...] Even further savings could be realized by switching to solar or wind energy. The new study shows that the water intensity of these renewable energy sources, as measured by water use per kilowatt of electricity, is only 1% to 2% of coal or natural gas's water intensity.
"Switching to solar or wind energy would eliminate much of the water withdrawals and water consumption for electricity generation in the U.S.," Vengosh said.
Quantification of the water-use reduction associated with the transition from coal to natural gas in the U.S. electricity sector, Environmental Research Letters (DOI: 10.1088/1748-9326/ab4d71)
(Score: 3, Informative) by qzm on Wednesday October 23 2019, @08:08AM (15 children)
How exactly is this water 'used'?
Sure, Coal is horrible, dirty, radioactive, etc.. and some water is I believe used in the scrubbing of the smoke.
However 10,000 gallons per megawatt 'consumed'? I assume they actually mean 'used', and most of that water is returned almost immediately to the area, possibly warmer (pretty much all thermal generation does that).
However reading into the actual article, they DO talk about 'consumed' versus 'withdrawn', however the summary seems to be focusing on withdrawn as if it is consumed...
This is similar to the way water is 'used' in beef farming for example, there the water is actually 95% a closed cycle with a period of only days, or weeks at most...
Still, gotta spin the spin.
Really... there are PLENTY of other reasons to hate on Coal, this is hardly one.
(Score: 4, Informative) by Anonymous Coward on Wednesday October 23 2019, @08:53AM
"Consumed" for cooling ... sad, but true. Journalists can't even think properly before writing BS sometimes, even when they have proper sources. But I guess they write sometimes, not think. You can see that immediately with "per megawatt electricity produced"... No such thing. Megawatt is unit of power, not energy. You don't produce "megawatts" - you produce Megawatt-hours.
Now, 10,000 gal. of water is about 40,000 liters which has heat capacity of 4.1J/C/g. That's 40m3, so basically fits in one 20ft. cargo container. So specific heat capacity of 40k liters is 4.1 * 40e6 = 160e6J/C. 1 MWh is 1e6*3.6e3=3.6e9J... or 3.6e9 / 160e6 = 22.5C. And since these thermal plants are running is 30% thermal efficiency, this looks like 1MWh-electric at your socket causes 40 tonnes of water to be evaporated at the cooling towers, in dust control and similar.
So, it's *consumed* would be right.
Gas is more like 60% efficient, which by definition must use less water per MWh.
(Score: 0) by Anonymous Coward on Wednesday October 23 2019, @08:59AM (1 child)
every day person A needs N gallons of water.
some of it for the coal, some of it for the cows, some of it to water the crops.
it doesn't matter when A can recover the water from the coal or cows or crops, A needs all N gallons today.
this study says that by moving away from coal the N gets smaller.
while you may not see the benefits, there are many places who right now need more water than locally available.
for the local solution, A can benefit from less water-hungry energy production methods.
ideally A can reduce their consumption so much that B can move to the same location and use the rest of the water for a similar operation.
(Score: 1) by khallow on Wednesday October 23 2019, @11:25PM
(Score: 4, Informative) by c0lo on Wednesday October 23 2019, @09:40AM (1 child)
Your assumption may be wrong under a number of conditions:
1. if the water is evaporated, then it will be returned "to the volume" instead of the area. In any case, you won't get to consume it. And you will need to evaporate water to cool down the steam you obtained during the heating stage when you burn coal.
2. If the water is used for pollution control (dust settling, flue scrubbers, etc),. you may get it back, but again you won't be able to consume it.
I seem to remember you could directly burn a fluid (gas or aerosolized liquid) and use the expansion of the combustion gasses to directly drive the turbines - the jet planes do it all the time. Looks like gas powered power plants [wikipedia.org] use a combined cycle, in which first stage is the direct extraction of energy from combustion gasses and the second stage uses steam (which need to be cooled back to water). I'm not surprised the amount of water consumed this way is smaller.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by RS3 on Wednesday October 23 2019, @01:10PM
Good points, and I'll augment: I'm much in favor of renewables, but it will be many years until there's enough implementation to eliminate coal, gas, nuclear, etc. I'm not sure of the costs for nuclear vs. equivalent size renewables. One of many problems for nuclear is the very long construction time, so it may be better to put the $ into renewables. And of course that's being done.
All that said, I'm not an ME (am EE) but studied thermodynamics and have some broad understanding of many technical things. I like your thinking re: gas turbine rather than steam turbine. Most power stations are built around huge gigawatt generators. I surmise it would be completely impractical to try to build a gigawatt gas turbine, and for whatever reason, water/steam is always the intermediary. You could build a plant with many gas turbines, and I think the idea is worth investigating. I'm not sure of the overall energy efficiency of many small gas turbines vs. 1 large steam turbine though... That would be a huge consideration.
Maybe 30 miles from me is a nuclear generation station situated next to a river. They do use the river for cooling water, and most is pumped back into the river. There is boating and swimming in said river, and I've water-skied, and thus been in the river, just downstream from the nuke. You could feel slightly warm currents here and there, but nothing worrying, etc. Recently a news article talked about some nukes in Europe which had to run at lower capacity due to excess river water warming. Point being- much of the heat goes into water bodies, and it's monitored and controlled. Yes, eventually it increases evaporation in rivers and oceans. But otherwise the river does not seem to suffer any ecological ill effects.
Also, I have a friend who used to work at the station, so I have some inside info. There are 2 large cooling towers, and some days they emit large vapor clouds, but often there's nothing obvious, because they use the river for cooling, and if they're adding too much warmth to the river, they crank up the cooling towers.
There is strong evidence and argument regarding water vapor, visible or not, being a huge contributor to atmospheric heating.
(Score: 2) by shortscreen on Wednesday October 23 2019, @09:53AM (2 children)
I'm also wondering how converting all the coal plants would result in more water savings than the total amount that is even being used to begin with.
(Score: 3, Touché) by c0lo on Wednesday October 23 2019, @10:18AM
[Citation needed]
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Wednesday October 23 2019, @11:59AM
They probably meant water usage for industry (not power generation and agriculture) vs. coal plant conversion change and its impact on water usage.
(Score: 3, Interesting) by JoeMerchant on Wednesday October 23 2019, @10:07AM (4 children)
I'd consider water used in processing coal ash and other polluting activities to be "used".
All "used water," even sewage sent directly into the ocean, is recycled. Once it has been withdrawn from a usable drinking aquifer and not directly returned to that same aquifer (as does happen with some thermal ground cycles), I'd consider that water "used" and needing to be recharged into the less than 1% of water which "accessible and fresh".
https://www.usgs.gov/special-topic/water-science-school/science/where-earths-water?qt-science_center_objects=0#qt-science_center_objects [usgs.gov]
🌻🌻 [google.com]
(Score: 2) by DeathMonkey on Wednesday October 23 2019, @05:25PM (3 children)
They're just recycling an armchair complaint that doesn't apply to this case.
Wastewater from the oil and gas industry is primarily disposed of through wastewater injection. They take the polluted water and inject it down the borehole to displace additional gas.
The gas is below a layer of impermeable shale and is very far below the water table. So this water does not end up back in the aquifer.
(Score: 3, Interesting) by JoeMerchant on Wednesday October 23 2019, @06:42PM (2 children)
I ain't heard slick talk like that since I left Houston... you got oil money in yer family or what?
🌻🌻 [google.com]
(Score: 2) by DeathMonkey on Wednesday October 23 2019, @07:50PM (1 child)
I do environmental compliance work for the oil and gas industry.
(Score: 2) by JoeMerchant on Wednesday October 23 2019, @08:16PM
Yeah, we knew a Pelican washer when we lived in Clear Lake... so, when you say you "do it for the industry" who signs the paychecks?
🌻🌻 [google.com]
(Score: 2) by DeathMonkey on Wednesday October 23 2019, @05:23PM
Wastewater injection (y'know the cause of all those earthquakes)
They take their polluted process water and pump it back down the borehole to displace the gas.
(Score: 2) by Osamabobama on Wednesday October 23 2019, @08:07PM
It looks like they go out of their way to clarify that they don't mean merely 'used'.
Appended to the end of comments you post. Max: 120 chars.
(Score: 1, Troll) by Arik on Wednesday October 23 2019, @09:14AM (16 children)
I didn't actually track down the original paper and read it. But just from the abstract this reeks of buzzwords for grants academia.
If laughter is the best medicine, who are the best doctors?
(Score: 5, Insightful) by GreatAuntAnesthesia on Wednesday October 23 2019, @09:35AM (11 children)
Right. By that logic, I could solve the world's water problems with a single litre of water. I give it to a thirsty person to drink, but it's "still there" as urine, which will eventually make its way back into the hydro cycle to be cleansed and then drunk by the next person, and the next, and the next...
By removing this water from the ground / river and putting it into the sky, you stop it being used in some other way. OK, it might become available for use elsewhere much later, but it's needed *here* and *now*.
(Score: 2, Disagree) by Arik on Wednesday October 23 2019, @09:44AM (8 children)
Doesn't take all that long. But yes, if this is being done in an area where water is scarce, /that/ could be a problem.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by JoeMerchant on Wednesday October 23 2019, @10:12AM (5 children)
There are still places (Switzerland, for example) where fresh drinkable water is available in overabundance. People do tend to congregate in those kind of places.
With 8 billion people sucking on the straw, those places are becoming quite rare. India, for example, made a real mess of trying to access their abundant, and arsenic laced, groundwater.
🌻🌻 [google.com]
(Score: 1) by Arik on Wednesday October 23 2019, @10:23AM (4 children)
Also a tremendous problem with pollution.
I hope they sort that out.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by JoeMerchant on Wednesday October 23 2019, @10:31AM (3 children)
You don't support 1300 million people without abundant water.
The real problem with the groundwater was that they irrigated croplands with it and the contaminants quickly built up in the topsoil to toxic levels. So, croplands that used to be useless due to lack of water became useless within a decade or so due to toxic contamination.
The World Bank: turning farmland into a non-renewable resource since 1969.
Actually, IDK if World Bank was behind the borehole initiative, it was some bunch of multi-national do-gooders who came, drilled, saw a bunch of smiling faces and went home feeling good about themselves. When the episode fades into antiquity it will probably be covered in the same historical paragraph as Roman soldiers salting enemy croplands.
🌻🌻 [google.com]
(Score: 1) by Arik on Wednesday October 23 2019, @10:34AM
If laughter is the best medicine, who are the best doctors?
(Score: 2, Informative) by Anonymous Coward on Wednesday October 23 2019, @12:20PM (1 child)
World Bank provides capital for projects like this. But it's not their purpose to check if the project is done correctly. That's up to local authorities.
As always, the contractors cheat to lower costs and the government has poor oversight. Then everything gets fucked over. But the fucking was not done by World Bank!
(Score: 0) by Anonymous Coward on Wednesday October 23 2019, @01:15PM
But notice how fucking and $ always seem to be interconnected.
(Score: 0) by Anonymous Coward on Wednesday October 23 2019, @10:57AM (1 child)
Consumed means consumed, no matter the abundance of the pool from which it is consumed.
(Score: 1) by Arik on Wednesday October 23 2019, @11:07AM
If laughter is the best medicine, who are the best doctors?
(Score: 2) by JoeMerchant on Wednesday October 23 2019, @10:09AM
Less than 1% of water on Earth is "accessible" to use as fresh liquid water, when we suck on that resource we tip the balance toward the other 99%
🌻🌻 [google.com]
(Score: 1, Informative) by Anonymous Coward on Wednesday October 23 2019, @12:03PM
Much later? Hours/days later, more like. Not 'much later' like months or years. In most cases, it will fall and end up in water/ground table. Sometimes, the ocean.
But ocean water is *constantly* picked up via evaporation, then dropped as rainwater on the continents. It's why BC is so rainy, why it's a rain forest. In the winter, BC's land is close to 0C. Air over the water is at 10C, 15C due to ocean currents. Via evaporation, drier air picks up water vapour... and then when it hits the land, it cools, and can't hold all the water.
I agree that ground water is indeed useful deep in the continent, but most power plants draw from rivers for cooling and what not.
I think the real complaint here is 'consumed'. Horse radish to that, people need to use words that mean the right thing. If I consume a piece of meat, it isn't meat coming out the other end. It's not like it can be 'cleaned' and restored to the same thing going in, either. Water? In most cases, it's water not fit to drink, turning into water fit to drink!
Yup.. water from river (not fit to drink, typically), ends up in the air, and eventually falls as pure H20.
And btw, water pulled from ground water tables doesn't always stay 'pulled'. I live on a well, and when my septic system processes water -- it ends up back in the ground table. For some, this isn't the case.. but for me it is.
(Score: 2, Insightful) by Anonymous Coward on Wednesday October 23 2019, @09:49AM (2 children)
Good luck quenching your thirst with water vapors.
' cause I'm too sexy for my cat
Too sexy for my hat...???
Or otherwise why? You such a genius or inspired by Gods you can afford to cast The Truth to the world without needing to read and much less to study?
Or is your ignorance just as good as a researcher's science?
Or is it that you like slinging bullshit and see what sticks and what doesn't?
Or... maybe you can enlighten us?
(Score: 0, Troll) by Arik on Wednesday October 23 2019, @09:52AM (1 child)
It is exceedingly rare for an abstract that reads like buzzword nonsense to be associated with a paper worth an hour or more of my time find a 'pirate' link for.
If laughter is the best medicine, who are the best doctors?
(Score: 0, Troll) by Anonymous Coward on Wednesday October 23 2019, @11:18AM
Too bad one can't peer-review your claim. Also, you have little skin to lose if you bullshit, while the author(s) of TFA put their real name and career on the line.
Oh, yes, here we go down the "too sexy for my cat" path again.
If it doesn't worth your time to search and read it, how come you see bullshiting S/N as worthy?
The rational choice would be to abstain from both, but I'm not that naïve to expect a rational choice from you.
Guess what, buddy? If I need to choose between two conflicting claims, a non-peer-reviewed one and one that has been peer-reviewed, my experience tells me it's exceedingly rare for the first to be true and the second to be false.
I'll call bullshit on this one.
(Score: 5, Insightful) by Anonymous Coward on Wednesday October 23 2019, @12:26PM
And this is all we need to know to figure out how much value to attribute to your "opinion".
And here we have another perfect example of the anti-intellectual wave that's been plaguing society for the past few decades.
(Score: -1, Redundant) by Anonymous Coward on Wednesday October 23 2019, @09:58AM
You're welcome.
(Score: 3, Interesting) by MrGuy on Wednesday October 23 2019, @11:03AM
So, lemme get this straight. Your water savings calculation show that the coal fired power industry, BY ITSELF, accounts for more than 100% of current industrial water use? That’s....not how percentages work.
If (to be incredibly generous) the author is being misleading by comparing a number for GLOBAL water savings with a US number to make a big, scary point, we’ll, it’s still extremely suspect. The US is one of the larger users of coal power, and even if it’s only 10% of world usage, that would still imply that upwards of 1/4th of the US’s industrial water use (probably more than 1/3, since even gas plants use some water) is currently consumed specifically by coal fired power plants. That...seems like a lot. Water has an awful lot of industrial uses.
(Score: 1, Troll) by Phoenix666 on Wednesday October 23 2019, @12:31PM (5 children)
The authors of the paper are such gloomy guses. Look, the more CO2 that gets pumped into the atmosphere, the more of the sun's energy the atmosphere retains. The more energy the atmosphere retains, the warmer it will get. The warmer it gets, the more water evaporates from the world's oceans, and that water forms clouds and falls back to the earth in the form of rain.
So coal use use is accelerating the rate at which pure, clean water will fall from the sky. You're welcome.
Washington DC delenda est.
(Score: 2) by c0lo on Wednesday October 23 2019, @12:56PM (1 child)
There's no warranty that water will fall where and when is needed.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Wednesday October 23 2019, @02:14PM
I wanted to say woosh but then I saw GP's username.
I think you're speaking to deaf ears here.
(Score: 0, Troll) by Azuma Hazuki on Thursday October 24 2019, @01:33AM (1 child)
Jesus tapdancing Christ. You must be taking the piss...
I am "that girl" your mother warned you about...
(Score: 2) by Phoenix666 on Friday October 25 2019, @11:14AM
Shhh, don't spoil it!
Washington DC delenda est.
(Score: 2) by takyon on Friday October 25 2019, @11:20AM
Acid Rain
Some stay dry and others feel the pain
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by hendrikboom on Wednesday October 23 2019, @08:43PM
This sounds like it takes 10,500 gallons to produce a megawatt.
However, a megawatt is a rate: energy per unit time.
10,500 gallons is a single fixed amount.
Am I to believe that a one-time use of 10,500 gallons of water will let us produce a megawatt, day in and day out, for eternity?
(Score: 2) by krishnoid on Wednesday October 23 2019, @09:02PM
So ... how many jiggawatts of electricity does the typical American household use in that same period?
(Score: 2) by Azuma Hazuki on Wednesday October 23 2019, @11:12PM (2 children)
Desalinization + nearshore wind farm, anyone? The idea is blindingly, stonkingly obvious. And it may make some projects that wouldn't be economically feasible on their own as simple power-generation concerns suddenly a lot more economically attractive.
I am "that girl" your mother warned you about...
(Score: 2) by takyon on Thursday October 24 2019, @12:06AM (1 child)
Solar is where it's at, still falling in $/W as far as I know, and obvious synergy with desalinization.
Desalination Project in California [soylentnews.org]
Device Converts Salt Water to Drinking Water Using Solar Power [soylentnews.org]
Water and Green Energy Produced by a Single Device [soylentnews.org]
Gas Plants Will Get Crushed by Wind, Solar by 2035 [soylentnews.org]
After that, pick a number between 15 and 50, add it to 2020, and enjoy down to earth nuclear fusion.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0, Redundant) by Azuma Hazuki on Thursday October 24 2019, @01:26AM
Even better :) I was thinking east coast with the wind/desal hybrid but solar/desal would be just what the doctor ordered for Cali!
I am "that girl" your mother warned you about...