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Collision Between Water and Energy Is Underway, and Worsening
An anonymous reader writes "This article is an eye opening perspective on another side effect of power generation — water usage: 'More than 40 percent of fresh water used in the United States is withdrawn to cool power plants. Renewable energy generally uses far less water, but there are glaring exceptions, such as geothermal and concentrating solar.' The article also mentions that power plants have to shut down if the incoming water is too warm to cool the plant. 'Also, even though some newer plants might use far less water, they could find that there’s far less water available as water temperatures go up and water flows go down. Another study found that nearly half of 423 U.S. plants were at risk of lower power output during droughts because their intake pipes for water were less than 3 meters below the surface.'"
More power plants = more greenhouse gases = global warming = higher seas
You know, assuming that all of these power plants output greenhouse gases. If not, someone needs to get on that.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
The fact that powerplants borrow water to cool themselves is no big deal. They give it all back.
That's probably even harder than trying to explain to what passes as an environmentalist these days that it's only steam rising out of nuclear power plants. They'll keep screaming that power plants burn babies to make energy and that they all need to shut down so we can go back to eating alongside sheep, which makes the whole cause look stupid.
Because, of course, planning for a few decades in the future costs money and requires political will. We'll let tomorrow worry about the problems we're creating! I'm so lucky to live in the Age of the Sociopath.
The world's burning. Moped Jesus spotted on I50. Details at 11.
What is even more ridiculous is the 40% number. Come ON! What about Agriculture. In CA something like 90% or our H2O usage goes to growing things. The power generation is tiny. Then there is the little detail that many of our power plants use ocean water!
I'm calling BS on that number.
Have you compiled your kernel today??
I live close to the new NSA data center in Bluffdale, Utah. Currently we are under a drought with widespread municipal water restrictions, yet the NSA surveillance center requires 1.7M gallons of water daily to operate.
The fact that powerplants borrow water to cool themselves is no big deal. They give it all back.
No, no, the article says "withdrawn" which means its not in the water bank anymore.
So at 40% per year, in two and a half years there will be no water left in the bank. We are Doomed.
To protect your future, you should run down and withdraw all your water from the bank today.
Horde it in your bed. (That's why water beds were invented).
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Water-cooled power plants take in water. And then they put it out again, warmer. They don't use it up. At worst some of it comes out as water vapor from cooling towers, which condenses out.
The Union of Concerned Scientists has a good guide on this; also distinguishing between water withdrawal and water consumption.
It doesn't seem entirely out of line. From my hydrology textbook last year: cooling edges out agriculture for water utilization nationally, and both are much higher than the third biggest, which I believe is landscaping use.
But hey, the textbook could be entirely wrong. I'm sure your 90% figure is well-sourced.
When you put generators down 5-6000 feet in deep fast ocean currents, which run virtually at constant speed year round, the amount of power available down there is staggering. Obviously it only works near coastline regions, but that is where the large populations tend to be, though not all coasts have deep water currents.
Superconducting long distance transmission lines are improving in capability, so maybe distance is not so much a problem in the future.
It is not technically difficult or polluting. We already put complex anchors and devices at those depths for oil drilling.
No need for radioactive stuff, no cooling, no dead birds, no pulsing noise to humans, no polution.
It takes damn good engineering, but that is what we are damn good at.
Start now.
If you would like to do a little further digging on unwise usage of water look into large scale ethanol production (not whiskey) http://www.swhydro.arizona.edu/archive/V6_N5/feature4.pdf sorry i don't know how to use html (I am a geek just not a good one!) My fancies lie in the chemistry and drug development distribution world....please forgive.
Life's journey is not to arrive at the grave safely in a well-preserved body, but rather to skid in sideways, totally wo
The study referenced in article says, "And in Texas, regulators denied developers of a proposed 1,320-megawatt coal plant a permit to with draw 8.3 billion gallons". Since USA has about 1100 GW of installed capacity (including hydro), this approximately translates into 7.5 trillion gallons or about 20 billion gallons a day. According to ucsusa, the total withdrawal by power plants is 200 billion gallons a day. So it looks like the old power plants are the main culprits.
The number seems fishy to me...because every power plant I've ever seen that was cooled with fresh water sits on a lake. The water enters the plant from the lake, cools the steam coming off of the turbine(s), and goes back to the lake. Some of it first goes through an osmosis filter for demineralization; that water becomes the steam that directly turns the turbine. But yeah...it's not like any of the water is destroyed or even vented as steam to the air. And the water they use isn't directly potable; they aren't drawing the water from the water mains. (Water mains don't supply enough water for it to even be feasible.) There is one exception, which is combustion turbine plants. But these are smaller, and use a very small amount of water for cooling in the same way our car radiators do; the consumption from these is almost negligible. (Come to think of it, has anyone checked out how much fresh drinking water gets used by all of our cars, in our radiators?)
Now, what they do say about how in heat waves some plants have to shut down or reduce their output because the water gets too warm...that fits. I've been on a lake attached to a fairly standard-sized coal-powered plant, and you could definitely feel the difference between where the intake of the plant was and where the output back into the lake was. It was that big of a difference; these plants put a LOT of heat into the water.
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There are closed loop systems, but you still need to cool and condense the steam back to water just to pipe it around, and re-heat it. Pushing spent (low pressure) steam back into your heating plant is no where near as efficient as sending water in. Condensing to water and pumping that is actually more efficient.
Most electrical generation plants have two or three stages of generation, where the steam exiting the high pressure turbines is re-heated with with flue gases and
sent through the medium and low pressure turbines. At the end of the line they have extracted just about all the heat they can from it.
The problem is we have no really good use for the remaining heat of spent steam. And no way to extract the remaining heat into a useful form, or
recycle it back into the plant or any other economical use.
So we essentially heat the atmosphere, by venting it into cooling towers.
But the water? It all gets returned to the cooling pond, except that bit that you see rising as vapor (its not steam) above the cooling towers.
.
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Well, it is true that we use 40% of our water for cooling energy plants, but that is kind of small in comparison with the fact that we use 10 million percent of our water, and growing by the second.
If you are not allowed to question your government then the government has answered your question.
The study is more about the risks that power plants may not have enough water available, not that they are using it up. The plants are competing for the water with those that do consume it, such as agriculture and residential, exacerbated by long term drought cycles in some areas, and climate change.
There are some uses for spent steam and even warmed water from the condensers but they are somewhat limited. My brother was involved with designing a combination generating set fuelled by natural gas which also produced process steam for sugar refining. Previously the sugar company had bought in electricity and produced low-pressure steam separately in gas-fired boilers. Afterwards they sold excess generating capacity to the grid and improved their financial bottom line by a healthy chunk.
Total water withdrawals in the United States for 2005 were estimated for eight categories of use: public supply, domestic, irrigation, livestock, aquaculture, industrial, mining, and thermoelectric-power generation (fig. 1). Thermoelectric power was the largest category of water use, followed by irrigation and public supply
Page 5 has pictures and data, you might like that.
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Most power plants built the lake in the first place. And they don't discharge into the lake; they discharge at or downstream of the dam -- so they aren't pulling in their own hot water. Next to none (read: NONE) of the intake water is used in the turbine steam loops -- those are 100% closed loops, if you're losing water you have a problem. (a serious problem for nuke plants.) [note: steam loops use distilled water -- ZERO minerals, RO reduces the mineral/particle volume, but it's not zero.]
That said, there are still numerous plants that use evaporative cooling towers. And they do, indeed, require a significant volume of water that is "consumed" -- it goes up as vapor. While it isn't "drinking water", it's water that's not available to the filter plant that feeds your taps. In a drought, you have a choice... cool the power plant, or have water to drink.
What about using nuclear (reduced life cycle greenhouse gasses, yes, we need diesel to mine uranium/thorium) with a closed loop system through the heat exchangers? The problem is plants that tap well, river or ocean water, and run it through evaporative cooling towers. This problem is created by the economic advantage granted to building gignormous plants that can't dispose of heat easily to their cool heatsink (thermodynamics baby) in order to do work. Now about a small nuke plant like the naval reactors that doesn't generate the enormous amounts of waste heat?
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If the "pollution" is just heat then you can solve it completely. It just costs more for holding ponds or multiple outlets. If the water temperature a few metres away from the outlets is close to ambient the problem is solved.
Most power plants built the lake in the first place. And they don't discharge into the lake; they discharge at or downstream of the dam -- so they aren't pulling in their own hot water. Next to none (read: NONE) of the intake water is used in the turbine steam loops -- those are 100% closed loops, if you're losing water you have a problem. (a serious problem for nuke plants.) [note: steam loops use distilled water -- ZERO minerals, RO reduces the mineral/particle volume, but it's not zero.]
That said, there are still numerous plants that use evaporative cooling towers. And they do, indeed, require a significant volume of water that is "consumed" -- it goes up as vapor. While it isn't "drinking water", it's water that's not available to the filter plant that feeds your taps. In a drought, you have a choice... cool the power plant, or have water to drink.
Regardless of who built it, a lake is a closed body of water, period. And yes, they DO discharge into the lake, typically; if you take water out of a lake and release it into a river, you drain the lake. I'm not guessing at this; I work for the very large civil engineering company that is mentioned in the article; not only do we do a huge amount of work in the power gen world (we're building the second-largest power plant in the world in South Africa right now), but 30% of the world's drinking water comes from water purification or desalinization plants that we built. I've been doing NERC CIP compliance work since before the auditing deadlines for the first 18 requirements (NERC CIP was implemented in stages at first), so I've spent about 6 years in the power industry by now, at about two dozen utilities in total.
And you're right, next to no water is used in the steam loops, but some is...as I said. Enough is important that the demin plant is considered a critical asset if the plant itself is considered critical, and there's a large storage tank of demineralized water to give some cushion in case there's a problem with the RO filters. And you are right about the zero minerals, but every plant I've ever seen...CT or ST...used RO filters. They use a lot of them, in series.
But to get back on point...if you take water from a river and put it back in a river...or from a lake to a river downstream...you're still not using up that water. You're just moving it from one point to another. Again, neither is potable water, and it's not causing a net loss.
Evaporative cooling towers...also called passive cooling towers...are extremely rare outside of nuclear installations. They're very expensive to build in comparison. Even among energy engineers, they're something of a curiosity for the fossil generation world. So that won't add up to the 40% cited.
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Both use a large amount of water, esp. when you factor in the water needed to transport the tar sands via pipeline. And a fair amount of tar sands are in desert areas, where water is scarce.
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