Can Hoover Dam Become a Giant $3B Battery? (cleantechnica.com) 219
The Los Angeles Department of Water and Power wants to spend $3 billion to pump back the water that's flowing through Hoover Dam -- so it can flow through again later, during periods of peak energy demand. This generates a net profit for the dam's operators -- the pumping stations are powered by cheap solar and wind energy, while the dams are currently operating at just 20% of their capacity. An anonymous reader quotes Clean Technica:
The problem is that California has so much renewable energy available now, thanks in large measure to aggressive state mandated policies, that much of it is "constrained." That's utility industry speak for having to give it away or simply let it go to waste. In some cases, utilities in California actually pay other utility companies to take the excess electricity off their hands.
Why not store it all in some of Elon Musk's grid scale batteries? Simply put, pumped hydroelectric storage is cheaper than battery storage, at least for now. Lazard, the financial advisory and asset management firm, estimates utility scale lithium-ion batteries cost 26 cents per kilowatt-hour compared with 15 cents for pumped hydro storage. "Hoover Dam is ideal for this," Kelly Sanders, an assistant professor of civil and environmental engineering at the University of Southern California tells the New York Times. "It's a gigantic plant. We don't have anything on the horizon as far as batteries of that magnitude."
Why not store it all in some of Elon Musk's grid scale batteries? Simply put, pumped hydroelectric storage is cheaper than battery storage, at least for now. Lazard, the financial advisory and asset management firm, estimates utility scale lithium-ion batteries cost 26 cents per kilowatt-hour compared with 15 cents for pumped hydro storage. "Hoover Dam is ideal for this," Kelly Sanders, an assistant professor of civil and environmental engineering at the University of Southern California tells the New York Times. "It's a gigantic plant. We don't have anything on the horizon as far as batteries of that magnitude."
Interesting idea (Score:4, Interesting)
Re:Interesting idea (Score:4, Informative)
That was also prior to the CA aqueduct along I5. CA's water management is much more developed than it was back then. This idea is very straightforward, top off the battery with the "wasted" power and use it when needed.
Any amount is a net gain, it doesn't have to charge it back "all the way"
Re:Interesting idea (Score:5, Informative)
That's not true. The power plant was built along with the original structure. The dam was completed in 1935. In 1936 the water level in Lake Mead became high enough to begin power generation. Additional generators were added in 37 and 39. The final generator was added in 61, which might be where your confusion comes from.
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But the main function of it was water management. The generators are a added bonus.
The amount of water that can be released are set by the bureau of reclamation.
Re:Interesting idea (Score:5, Informative)
The Colorado River has many dams. Not very far down the river from Hoover Dam is Davis Dam and Lake Mohave. By pumping water from Lake Mohave to Lake Mead (behind Hoover Dam), they would be releasing the same amount of water while storing excess solar power.
This is a very unusual situation. You have two large reservoir forming dams next to each other on a large river cutting through a desert with great solar power generating potential.
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Just had a realization here: converting it to pumped hydroelectric might be a boon for the downstream environment.
There's been a number of negative consequences to the dam. It lets out water relatively steadily, so there's no longer any floods. These allow sediment buildup, both in Lake Meade, and downstream. They also have made the river more hazardous to navigate, as rockslides have built up. The deep water is the average temperature of the water year round, so there's no longer summer heat nor winter c
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You're quite right, and it's not a problem just with Hoover Dam but with any large hydro dam in the Southwest -- including Shasta, Oroville, and dozens of smaller dams. One problem is that you have to move a LOT of water to store power. Roughly, one cubic meter (one metric tonne) needs to drop 100 meters (328 feet in American) to generate one kw/hr of electricity. Pumped storage using existing dams will mean moving a lot of water and one does need to balance water usage in the generally water short South
Been there, done that... (Score:2)
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The other option is a dam upgrade.
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Except wind and solar are orders of magnitude cheaper and easier in every way than nuclear, but other than that yeah you're right.
Orders of magnitude? Citation needed. Here's mine:
https://www.instituteforenergy... [institutef...search.org]
On shore wind, nuclear, and coal are all about the same cost, within the error bars of each other. Solar is expensive, and needs storage to follow load, making it cost even more. Wind also needs storage but if coupled with natural gas (the cheapest means we have to produce electricity right now), coal, and nuclear then it's a viable energy source. Assuming the goal is reducing CO2 then we'll rule out coal, leaving nuclea
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I noticed no citations in your post.
Re:Well sort of, but you're missing a key point (Score:5, Funny)
I've got a Chevy Citation that I'm going to use to run your stupid face over with. Go to wikipedo if you want.
I did go to Wikipedia, that's how I found the citation I gave in my previous post. I'm curious how you came to believe nuclear to be orders of magnitude more expensive than wind and solar. I must have missed what you saw on Wikipedia. Help me out and point to where you found what you believe you found.
You really are a useless cunt aren't you.
That may also be true, but I'd like a citation on that as well.
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Build a second dam.
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Build a second dam.
It's dams . . .
. . . all the way down.
Re:Well sort of, but you're missing a key point (Score:4, Insightful)
They got the cost right, but it's a cost for capacity not a cost added on to each KWh delivered.
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According to TFA the pumping station will be 20 miles down river. If the water is traveling at say 5 MPH they have 4 hours from passing through the dam to reaching the pumping station and being recycled.
Effectively the river is used as a kind of delay line storage. Pretty cool.
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If I pump it up twice as far it costs twice as much energy to pump it up, but I get twice as much when it comes tumbling back down.
Is there something I missed here, something that doesn't scale linearly?
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Is there something I missed here?
Yes. The power generation uses the potential difference between the level of Lake Mead, and the level of the outlet. If it then flows downhill for an additional 20 miles, no power is generated from that.
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If I pump it up twice as far it costs twice as much energy to pump it up, but I get twice as much when it comes tumbling back down.
Is there something I missed here, something that doesn't scale linearly?
You only get energy from the drop of water through the dam. The potential energy of the next 20 miles is lost. However, you bring up a good point in that if you are going to go through the cost of pumping water 20 miles upstream through a pipeline, it would make more sense to have reversible pump/turbines at the lower reservoir and then get more of that potential energy back.
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Pretty stupid. 20 miles down river means it is at an even lower elevation, meaning you have to pump water even further vertically with that much more efficiency loss. A typical pumped hydro has a reservoir at the base of the hydro outlet for a very good reason.
The only relevant things here is the cost of building the return pipe system, and the amount of extra electricity at high value times they can get out of it, and thus the levelized cost of that electricity. That only part of the electricity (that otherwise would have been 100% wasted) is recovered is irrelevant.
More power could be recovered if a second dam was built, to create a second lake with a level just below the Hoover Dam outlets. But whether this additional power produced would be worth the cost of
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Pretty stupid. 20 miles down river means it is at an even lower elevation, meaning you have to pump water even further vertically with that much more efficiency loss. A typical pumped hydro has a reservoir at the base of the hydro outlet for a very good reason.
The only relevant things here is the cost of building the return pipe system, and the amount of extra electricity at high value times they can get out of it, and thus the levelized cost of that electricity. That only part of the electricity (that otherwise would have been 100% wasted) is recovered is irrelevant.
More power could be recovered if a second dam was built, to create a second lake with a level just below the Hoover Dam outlets. But whether this additional power produced would be worth the cost of building this dam, and the hassle of getting approval for a second lake, is questionable.
What electricity would be 100% wasted, and why don't you think efficiency matters what it comes to cost?
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The problem is... where's the lower reservoir? The Colorado River isn't going to run backwards for you.
Also:
I assume they mean 2,6 and 1,5 cents, respectively.
Exactly. The Hoover Dam is a national monument, and this idea is monumentally stupid. Large dams like the Hoover constantly let water through because it is required to keep the river flowing. So you would need to let more water flow through to keep the river flowing.
Even if it made sense you'd have to carve out a large lower reservoir near the base of the dam. That fact the "Cleantechnica' didn't even mention this is a testament to their prowess at energy solutions.
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The only thing that seems to make sense to me - without destroying more landscape - is if they cut Lake Meade in half with a second dam, and had both a "high lake" and a "low lake". Of course, that would mean that the water behind Hoover Dam would generally be at rather low levels, and the water further upstream generally at high levels. Not sure how that would affect recreation. Might slightly increase evaporation / ground losses, too.
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Large dams like the Hoover constantly let water through
No. Water flows only during periods of peak power demand.
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Large dams like the Hoover constantly let water through
No. Water flows only during periods of peak power demand.
https://www.usbr.gov/lc/region... [usbr.gov]
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As for letting more water through, all of the discharge from Hoover Dam currently goes through its powerhouses at a fraction of their peak capacity. This plan would use excess power t
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Just did some checks with a clickable elevation map
Nominal elevation of Lake Meade: 372m
River at the base: ~223m (hard to tell)
Nominal elevation of Lake Mohave: 198m.
So looks like you lose about 25m between the dam and Lake Mojave.
If Lake Meade were relatively full, 25m losses wouldn't be that great. They become more significant the lower the dam height, of course.
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The elevation of the lowest Hoover Dam outlet is 272 meters, well above the river level, and the lowest Lake Mead elevation that produces electricity is 320 m. You get your biggest energy return if you pump the water up when Lake Mead is high. In that case you are raising it 174 m, and then getting 100 m of water drop back out. If it is at low water level you are raising it 122 m for a 48 m drop. So a 57% return (neglecting other losses) versus a 39% return.
You could raise the level of Lake Mojave, or build
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I've toured Davis Dam (before they discontinued the tours). One item I found interesting was that the dam wasn't running at 100% of electricity capacity. They used it to handle peaks is what we were told.
It would be interesting to understand how much power both Hoover, Davis and Parker dams produce and whether or not they're running at capacity.
I'm wondering if the dams are running at 100% at peak times or not.
Call me "Sherlock Hog" (Score:2)
I deduce from the TFA's suggestion to use Elon Musk's batteries that the anonymous submitter is none other than yourself.
How do you plead?
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There are two reservoirs downstream from Lake Mead.
Lake Mojave and Lake Havasu.
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The problem is... where's the lower reservoir? The Colorado River isn't going to run backwards for you.
The whole lower Colorado below Hoover Dam is a stairstep of lakes behind smaller dams. The idea in TFA was to use the lakes behind Parker and Davis as the lower reservoirs to implement pumped storage behind Hoover. I maintain this would not be necessary if we used the fluctuating energy to desalinate on the Pacific coast, serving local cities.
Every drop of Colorado River water is allocated to downstream users, with the last muddy trickle being used by Mexico. Since the partition treaties and dam constructio
As does California, several, for a long time (Score:3)
As does California, several, some of which it has had for a long time. For instance: The San Luis reservoir / O'Neil Forebay complex.
San Luis reservoir was completed in 1967 and has a capacity of just over 2 million acre-feet, about 319 feet above the forebay. The forebay is at the level of the local section of the California State Water and Central Valley Projects, while the reservoir is filled by pumping and generates power
You need excess power AND water (Score:5, Insightful)
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My assertion would be that the water can be available. First, we are not talking about a continuous supply of water that will either be sequestered long term or wasted. For instance about a third of California water is used to either grow alfalf
If you have mountains and 100sq miles to destroy (Score:2, Informative)
Yes, this makes perfect sense in the right location. Mountains with the right geography, and of course building the dam flooded 100 square miles. So where you have just the right geography, and you don't mind destroying everything upstream for hundreds of square miles, at can make sense. Well, except consider Banqiao.
As Banqiao and other dams show, you also need to be okay with destroying everything downstream for many miles. Given all those conditions, it works well. Hoover dam is one of very few places i
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Ot the argument against being a vegetarian since organic vegetables are more expensive than chik fil e
None of this occurs in a vacuum, and one can't win an argument by saying a new solution is going to be destructive, unless the current solution is 100% non destructive, which nothing is because entro
Unless you want it to be reliable (Score:2)
One way to divide power systems is those that need to be reliable versus those that can be used whenever they happen to be available.
A few hours of storage is useful for "if we happen to have that's cool, if not we'll just use the natural gas plant". Large storm systems and other weather patterns can easily last several days, occasionally a week or more, so if you want to make weather-dependent power reliable, you need at least a week of storage.
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Hoover Dam is in Nevada. But note, the water isn't lost when it's pumped back behind the dam, it's only delayed.
Currently, Hoover is operating at 20% capacity. It needs to stay at least at that level for the sake of water management downstream and not overflowing lake Mead. However, that doesn't mean it can't spill more during peak demand (instead of running fossil fuel plants) and pump the excess back when renewables are producing a surplus.
Sorry, but I have to say it (Score:5, Funny)
"That's one dam expensive battery."
I'll go home now.
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Serious investment, but low operating costs(;-))
Brazil has used it for years, here's an IEEE story on the current status https://ieeexplore.ieee.org/do... [ieee.org]
Marmora has a proposal for the same in Ontario, https://marmoraandlake.ca/pump... [marmoraandlake.ca]
The part I don't really understand (Score:2)
"In some cases, utilities in California actually pay other utility companies to take the excess electricity off their hands."
I don't really understand paying to get rid of surplus electricity. Isn't the point to sell electricity?
Also is there additional room for more generators? Or to update the existing ones? I would hope generator technolofy has advanced since 1961
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I don't really understand paying to get rid of surplus electricity. Isn't the point to sell electricity?
No, the point is to make money.
Because of subsidies for wind and solar there is an incentive to "sell" electricity at a negative price. Let's consider a scenario of wind and solar getting a subsidy of 5 cents per kilowatt-hour when electricity is on average costing about 10 cents per kilowatt-hour. The costs borne by wind and solar are in capital, labor, and so forth, and nothing for fuel. They want to get paid as much as they can, as often as they can. If that means paying people 2, 3, or or even 4 cen
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Another point to add to the discussion- base load power plants are slow to change their output levels. They are designed to operate at a fairly constant level. Peaking plants are used when necessary to meet higher demand. If the demand goes below the base generation level, there's going to be extra electricity on the grid because they can't reduce the amount generated quickly. This is the "excess electricity" that needs to be sold.
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Too much power available. (Score:2)
Remember when people used to talk about how nuclear would bring about a future where power was "too cheap to meter"?
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Remember when people used to talk about how nuclear would bring about a future where power was "too cheap to meter"?
No. I've read about it though. How old are you? I'm pretty sure those claims died out in the 1960s or 1970s. Three Mile Island and the movie China Syndrome put an end to claims of being too cheap to meter, as far as I can tell. Those were in 1979 but the protestations on nuclear power predated both by quite a margin. "Too cheap to meter" would have been in the days when Thunderbirds and Star Trek were on TV, which were visions of a nuclear powered future.
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Desalination plants are capital intensive. You cannot economically run a desalination plant on surplus electricity for a few hours a day, you need to run it almost continually. You can probably get away with shutting it down for a few peak-hours a day though.
The same is true for most of the other things people propose using free electricity for, such as hydrogen production.
CA has a consumption problem, not supply (Score:2)
Residential water use is under 15% of California's water supply - the rest is industry. If you want to do something about limited water, ban fracking, cattle ranching, almond & rice farming.
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Residential water use is under 15% of California's water supply - the rest is industry. If you want to do something about limited water, ban fracking, cattle ranching, almond & rice farming.
In other words ban the things that make money in the state, and therefore pay the taxes, and when the money runs out to pay for wind subsidies, public education, and all the other goodies the taxes pay for, the people will leave. That works for me... except the part where these people might come to my state.
Here's another idea. Build some water reservoirs, desalination plants, and power plants to make them work, and everyone can have water. If you want to argue that this would cost too much then consider
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Wrong wrong wrong wrong. [youtube.com]
The entire agricultural output [washingtonpost.com] of California is only 2% of the state's GDP. Meaning that entire sector could disappear and the state wouldn't even notice, economically speaking. But I'm not speaking of banning agriculture, only the most wasteful aspects of it.
And you noted the part that residential water use is less than 15% of the state's wat
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You mean spend fantastic sums of money just so said cattle ranchers and almond farmers can go on living beyond the water supply's means. How about....no.
I mean California should spend "fantastic" sums of money so people can eat, drink, bathe, and flush their toilets. Failing to do so could result in a sanitation nightmare. There's already an odorous fog about many California cities from the feces in the street and unwashed hippies.
California has had a water supply problem for a very long time. If they intend to keep the population happy and healthy then they need to get water from somewhere. It doesn't have to be from desalination but that's the most lo
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Desalination plants are ineffective, even more costly, and there are over a dozen better options including using the power to convince farmers to not waste so much water.
The farmers are "wasting" water? I grew up on a farm and like any business we went to great lengths to eliminate waste. I dispute your claim solely on the basis that wasting water diminishes their profits. You can claim they value money over saving water but I claim they save the water because they value money. What it comes down to is that California is unwilling to tell the "environmentalists" that the environment includes people. People need water for food, and the farmers know how to turn water int
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The farmers are "wasting" water? I grew up on a farm and like any business we went to great lengths to eliminate waste. I dispute your claim solely on the basis that wasting water diminishes their profits.
In at least Lake, Humboldt, and Napa counties, farmers are illegally selling water to maintain their allotment. If you don't use it this year, it gets cut next year. So even if they don't need the water, they pump it anyway. They can either waste it by pumping it into a creek or similar, or they can pump it into trucks and sell it to ganja farmers. Lots of them have been doing that latter thing. This is actually illegal, but they do it anyway. The fix is to stop dicking with their allotment when they don't
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Maybe the government could change their policies so that farmers are not encouraged to waste the water?
You are blaming the farmers for acting within the rules, rules that encourage them to waste water. Don't hate the player, hate the game.
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Maybe the government could change their policies so that farmers are not encouraged to waste the water?
That is literally what I said was the remedy. Are you an idiot or a troll? Wait, you're a trolling idiot.
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With gov inspectors out all over the state understanding the amount of water used.
Tamper proof ways of counting water use.
Welcome everyone. I am your dam guide, Arnie.... (Score:2)
Now I'm about to take you through a fully functional power plant, so please, no one wander off the dam tour and please take all the dam pictures you want. Now are there any dam questions?
Only downside - negative effects on the river (Score:2)
If water levels continue to drop in Lake Mead, this may really put a strain on the river and everyone down stream.
And this plan depends on Hoover Dam continuing to have enough water to work at all. With those decreasing levels in Lake Mead, it may be necessary to pump just to keep the dam running at 20%.
And pumping the water has to be done in a manner that protects the wildlife using the river.
With all of that said, this "virtual battery" of energy storage beats real batteries by a longshot, IMO. Much clean
Seen Lake Mead lately? (Score:2)
Battery cheaper by time they finish (Score:4, Insightful)
When looking at something of this scale, you can't use today's prices. I found several estimates of the rate of decline of cost in battery storage over the next few years and even the conservative ones put it at 70% of today's prices in 5 years. Since pumped storage is a very mature technology, it is unlikely to experience any decline.
The 15 vs 26 cent comparison in the article amounts to pumped storage being roughly 60% of the cost of battery storage right now. So, in roughly 7 years, the two should cross. And that doesn't take into account the likelihood of big advancements in utility scale flow battery storage which is likely going to replace lithium because it is not an application that cares about density or weight of the battery system so much as cost.
The likelihood of a project of this magnitude gaining all of its approvals and being completed in 7 years is slim to none.
This is just an attempt to slip some more billions into the old-money major construction industry.
It would be better to build much smaller scale projects with batteries placed closer to demand points. They would start coming online much sooner and each year the new projects can adapt to the latest, most cost-effective technologies. If you spread that same $3 billion over 15 years of battery buildout, the cost of the ones you're building near the end will be much less than that 15 cent per kWH mark and balance out the cost of today's expenditures. In addition, you'll be providing service within the first year. Mega projects always get eaten up by increased costs due to delays. A battery approach actually ends up having a decreased cost with delays.
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well written
And why are there not power-hungry businesses flocking in to take advantage of the cheaper electricity. It's not as if they can't build batteries for themselves to even out the flow in exchange for lower pricing. For that matter one would think that homes and offices or even small communities would be funding small scale batteries to cut electricity costs. I could see there being all sorts of ways that the utility could incentivize others to make this kind of investment. It might even boost grid
Fuel is storage, uranium is fuel... (Score:2)
If wind and solar needs storage to provide power that is inexpensive, low carbon, and reliable, then we need storage that is inexpensive, reliable and low carbon. That means we need nuclear power, because fuel is storage and uranium is a low carbon fuel.
Here's a short (about 2 minutes) video explaining the problem:
https://www.youtube.com/watch?... [youtube.com]
Here's a longer (24 minute) video explaining the problem in more detail:
https://www.youtube.com/watch?... [youtube.com]
We will see an expansion of the use of nuclear power beca
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Whatever problems people have brought up against nuclear power they have always been problems of policy, not physics.
It always costs more to decommission a reactor than the estimates, and The People always wind up footing the bill instead of the corporate cocks who made all the money. Nuclear power is never too cheap to meter, which is the lie which was used to sell it to The People. And both of those things are due to physics. You fail again, nuclear playboy.
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Every nation that has nuclear power also has a national fund to decommission them, paid for by the utilities that own the nuclear power plants. If the amount of money in these funds is insufficient to pay for the decommissioning then that is a failure in government policy to properly tax the utilities for this fund, or a failure of the government to control the costs of decommissioning.
Government estimates not meeting demands is not a failure of physics, that's a failure of government and policy to create
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Where are you going to get the various rare earths and other metals needed to prevent embrittlement of the structures and housing of the nuclear plant?
The problem of the USA not producing the rare earth metals it needs domestically is due to existing policy on producing thorium and uranium. Rare earth metals exist in the ground in ores that also have high concentrations of thorium and uranium. Removing uranium and thorium from the ground, and concentrating them as a byproduct of extracting the rare earth metals is, in the eyes of the federal government, "producing weapons grade materials" and places such mines under considerable scrutiny and regulations
Betteridge was here (Score:2)
The short answer is no.
The long answer is that a battery is a collection of chemical cells connected together to behave like a larger cell, so no, it cannot.
What's wrong with calling it energy storage? Isn't this supposed to be news for nerds, not oversimplifications for morons?
Perfect solution: Boil the ocean (Score:5, Funny)
Use the waste heat from bitcoin mining to boil the ocean. the covection will carry water up into the hills providing rain to prevent fires and the ground water will end up in lake mead where it can be used to make electricity to power the mining systems
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The thing is, this unused energy that would go to waste is quite some distance from the ocean.
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This is California we're talking about. The excess power should be used to create Dry Ice, thereby trapping carbon dioxide and saving the world from Global Warming.
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There's an excess of energy according to TFS and TFA. So what exactly are we wasting here?
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There's an excess of energy according to TFS and TFA. So what exactly are we wasting here?
What's wasted is the capacity to use that energy later, when it's needed.
Los Angeles has a chronic problem of a shortage of power production in the summer, when the sun is high and winds are low. They might have an excess of power in the morning with all that solar power but unless people want to cool their houses and buildings to freezing and then still have them get unbearably hot in the afternoon this will continue to be a problem.
Here's what I propose as an alternate solution, and I accept that this ma
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There's an excess of energy according to TFS and TFA. So what exactly are we wasting here?
What's wasted is the capacity to use that energy later, when it's needed.
Not really, the bitcoins can be used to buy someone else's excess when you are in need. :-)
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Los Angeles has a chronic problem of a shortage of power production in the summer, when the sun is high and winds are low. They might have an excess of power in the morning with all that solar power but unless people want to cool their houses and buildings to freezing and then still have them get unbearably hot in the afternoon this will continue to be a problem.
Wrong again. Has the radiation you love so much cooked your tiny little brain? All you do is you orient the solar panels such that they produce the most power when the power is needed most. Problem solved with solar and with no need for nuclear, once again.
I propose California build desalination plants along the shore to use that excess power.
Not cost effective, just like nuclear power.
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All you do is you orient the solar panels such that they produce the most power when the power is needed most. Problem solved with solar and with no need for nuclear, once again.
Citation needed.
I've seen the data and power is needed most shortly before sunset, when orienting your solar panels does nothing. Unless you are "orienting" your panels about 1000 miles off shore it's not helpful.
Not cost effective, just like nuclear power.
Citation needed.
I see that California has several desalination plants already, with plans for many more. I admit that pumping the water to another state could be more trouble than it's worth but building desalination plants is worth the trouble otherwise they would not be building them now, and i
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Nifty. Completed in 1976, delivers 110,000 acre-feet per year. Could be double that, but the Navajo grabbed half. https://en.wikipedia.org/wiki/San_Juan-Chama_Project [wikipedia.org]
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Desalination is a great direct use of fluctuating renewable power, because given the buffering effect of reservoirs there is no need to produce it at a constant rate. But desal water is better used right on the ocean, where most of California's people live. Greater Los Angeles alone is fourteen million people: pipe the renewable power to a giant desalination plant that serves the city.
If this were to be done, the Colorado water now headed to Los Angeles could now be retained in Lake Mead and/or sold to othe
Water from where? - Re:Pumping the water back up? (Score:2)
I was just about to write this. Where does the LA power company plan to get the water to put into the reservoir? If it's from water that is running downstream then this seems rather silly. There are probably easier ways to waste out electricity, which is what that would be doing. And as you say, if you just left the water in the reservoir, it can generate electricity when it flows out.
Of course they could be referring to other sources of water flowing nearby, but I don't think there are any.
Someone does
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Further to my comment, here's the reasoning I was getting at. If we take a certain amount of the downstream river's flow, call it f, and pump it back into the reservoir where it will be released at night, presumably increasing the flow by f (the overall flow in 24 hours is the same), then that's the same as simply reducing the dam's outflow by f during the day and increasing it by f at night. Same effect, but no pumping required. Am I incorrect in this analysis? This would be true for any pumped storage
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Pumped storage makes sense if the river does not have sufficient flow but the height difference is considerable. With pumps and a lower reservoir, you can reuse the same water several times.
However, pumped hydro is generally only worth building if you get to use the pumps at least once a day, you can't meaningfully use it to e.g. store energy from winter to summer (unlike regular hydro which often does that). Batteries will soon (as in within 10 years) be able to do intraday load-following cheaper that pump
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If the water comes from the dam in the first place, wouldn't it be more efficient simply to leave it there until needed?
They can't without damaging downstream ecosystems. A certain amount of water must be released continuously.
This wasn't an issue back when the dam was constructed. However in the intervening decades more and more water is being used by upstream customers along with greater environmental regulation requiring the dam to release water for downstream ecosystems. The end result is not enough water coming into the reservoir to keep water levels as high as they'd like.
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Except that the proposal is to take some of the flowing water downstream about 20 miles and pump that back. That's exactly equivalent to reducing the flow from the dam in the first place, and then later increasing it.
What am I missing? How is this different and not a complete and utter loss?
It's *stores* energy, like a battery. (Score:2)
Suppose you have a gallon of milk. In fact, go grab one from the fridge right now since this is unclear to you. As you've already considered, you can release some potential energy by allowing the gallon of milk to fall - it's weight could power a generator. Let's call the amount of power "one milk-fall". That's our unit of measurement.
Now if you were to lift it back up again and then use it's fall to power the generator again, that wouldn't be generating more power, because you'd be USING energy to lift it,
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I understand all that quite well, or so I thought. I was just wondering what I was missing in my analysis of the energy calculations. And that was the energy produced by the generator from the first fall through the turbines. Once that's taken into account, then clearly there is not an equivalence with simply waiting for the water. I knew I had to be missing something. Maybe the milk I just drank helped me see it!
Cool. (Score:2)
I love it when you the light bulb goes on.
Typo: not you (Score:2)
That should be:
I love it when the light bulb goes on.
I guess predictive text figured "I love ..." should be followed by "you".
I guess I love you too. :)
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They need to spill some water all the time so the people downstream don't end up without water.
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But if you pump the water back up then it won't be downstream for the people who need it. Or alternatively, if the people downstream use the water then how are you going to pump it back up?
I guess it depends what the people downstream need it for. If they're using it for swimming and boating that's fine, but if they're using if drinking and washing then aren't you really talking about pumping sewage upriver? Industrial uses or anything else that consumes or contaminates the water has the same issue.
You say
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The most obvious way to see it is to call the flow rate needed downstream as X. So during peak demand, we spill X + Y and generate power. When there is a surplus from renewables, we pump Y back up leaving X for the other uses.
Ideally you build a smaller reservoir below the dam to hold Y until it gets pumped back up.
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They are simply modulating the flow between Lake Mead and Lake Mojave,which is further downstream. Lake Mojave can release water at whatever rate it needs to. Since they are capturing the water above Lake Mojave, this water does not actually reach that lower lake at all, and its elevation remains the same.
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Except if they don't release enough water into lake Mojave, it will dry up. It does make things clearer though, they have a proper reservoir to pump from.
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Depending on the other power sources on the grid, it can make sense to pump.
Nuclear plants don't like to vary their output. They function best when outputting a constant amount of power 24/7. But power demand is roughly sinusoidal - a peak during the afternoon, and a trough in the early morning. So often they let the reservoir drain during the peak hours, and then use the excess power overnight to pump it back up. I've vacationed at an artificial lake that did this - the water level cycled by about two feet
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Trying to wrap my head around this. Would the overall total water flow be the same now as it was before the pumping system was created? Or does the Swiss system continually recirculate a certain amount of water? This makes a difference as to whether the energy is really being stored or if it's just an expensive way to heat water with electricity.
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That sounds like natural gas industry propaganda.
It's not propaganda if it's true. Right?
The natural gas people must just love those wind and solar subsidies. What wind and solar power need to provide reliable electricity is a source of backup power. Right now, in most every part of the world, this means natural gas. The difference though between burning natural gas in a thermal plant (meaning boiling water) and a turbine is that the turbine needs twice the volume of natural gas than the thermal plant for the same energy out. This is because a turbin
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You leave out of the equation building high voltage DC transmission lines to move the electricity to distant markets. 800 KV DC lines are used all over the world and the losses are only several percent even for transcontinental transmission. A better power grid for the 21st Century seems a logical and necessary idea. Power lines cost less than power plants over time. The power excess this article is discussing is only a local one due the lack of opportunity to sell it in more distant markets. A large part o
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You leave out of the equation building high voltage DC transmission lines to move the electricity to distant markets.
If you do that while still keeping the subsidies for windmills to produce power, even when that power isn't needed, then those power lines just export the problems of subsidies to other states.
California is just one pile of mismanagement on top of more mismanagement. They created this shortage of storage with an abundance of wind and solar subsidies. Stop subsidizing this and the problem will resolve itself.