Giving Old Dams New Life Could Spark an Energy Boom (msn.com) 50
"Extreme drought has drastically reduced reservoir levels and is causing a decline in electricity production from hydropower," reports the Washington Post.
"Yet while climate change has parched the West, these same forces have greatly increased precipitation in much of the Midwest, the South and the East. There, hydropower is gaining momentum, and supporters say that in many places it is poised for a big resurgence." And the Post sees this benefiting "a growing effort to retrofit so-called nonpowered dams, or any dams created for a need other than hydropower, for electricity production..." In 2016, a U.S. Department of Energy study forecast that hydropower in the United States could expand from its current capacity of 101 gigawatts to nearly 150 gigawatts by 2050. This growth would come not from new dam construction but from upgrading existing hydroelectric resources, adding pumped storage capacity, and retrofitting nonpowered dams for hydropower.... Nonpowered dams compose the vast majority of America's dam infrastructure. They can be found across the country, come in all sizes and were built to address a wide array of needs, including flood control, navigation, water supply and recreation.
Out of the estimated 90,000 dams in the United States, about 2,200 of them generate hydroelectric power. These hydropower resources, however, account for 7 percent of national energy production and contribute 37 percent of the nation's renewable energy supply....
Solar and wind produce energy intermittently, but hydropower can operate day or night, 24/7. Some hydropower facilities can shut down or ramp up energy production very quickly, providing energy grids with stopgap flexibility during peak demand or in the case of blackouts.... The addition of hydropower to nonpowered dams can be financially attractive to developers. Typically the dam's operation is not changed, so there is usually much less opposition from communities and environmental groups than there would be to a new dam project.
The article points out that last year's U.S. infrastructure funding included money to add hydropower to "nonpowered dams."
"Yet while climate change has parched the West, these same forces have greatly increased precipitation in much of the Midwest, the South and the East. There, hydropower is gaining momentum, and supporters say that in many places it is poised for a big resurgence." And the Post sees this benefiting "a growing effort to retrofit so-called nonpowered dams, or any dams created for a need other than hydropower, for electricity production..." In 2016, a U.S. Department of Energy study forecast that hydropower in the United States could expand from its current capacity of 101 gigawatts to nearly 150 gigawatts by 2050. This growth would come not from new dam construction but from upgrading existing hydroelectric resources, adding pumped storage capacity, and retrofitting nonpowered dams for hydropower.... Nonpowered dams compose the vast majority of America's dam infrastructure. They can be found across the country, come in all sizes and were built to address a wide array of needs, including flood control, navigation, water supply and recreation.
Out of the estimated 90,000 dams in the United States, about 2,200 of them generate hydroelectric power. These hydropower resources, however, account for 7 percent of national energy production and contribute 37 percent of the nation's renewable energy supply....
Solar and wind produce energy intermittently, but hydropower can operate day or night, 24/7. Some hydropower facilities can shut down or ramp up energy production very quickly, providing energy grids with stopgap flexibility during peak demand or in the case of blackouts.... The addition of hydropower to nonpowered dams can be financially attractive to developers. Typically the dam's operation is not changed, so there is usually much less opposition from communities and environmental groups than there would be to a new dam project.
The article points out that last year's U.S. infrastructure funding included money to add hydropower to "nonpowered dams."
Seems like a no brainer (Score:1)
Hoover dam isn't only there for Hydro power (Score:5, Informative)
It is also there to provide a steady flow of water below the dam for agriculture, as well as providing water for downstream cities.
This would be what is driving releases at the moment. Power generation might change the timing of the releases, but the amount released would be the amount of water needed downstream.
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It is also there to provide a steady flow of water below the dam for agriculture, as well as providing water for downstream cities.
Also for maintaining wildlife populations - especially fish and other water creatures.
Indeed, much of the thrashing of agriculture has been the result of government bureau or court mandated diversion of water from irrigation to supporting outflow for the benefit of allegedly endangered populations of fish - often in violation of the government promises during the funding of the
Re: Hoover dam isn't only there for Hydro power (Score:2)
Maybe that is a reason for some of its operation, but not its existence.
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US states are guaranteed 7.5 million acre-feet/year of water from the river under interstate compacts, and use 6.5; Mexico is allotted 1.5 under international treaty.
The total capacity of the reservoir is 29 million acre-feet, and is currently 31% full, meaning you'd need about 20 million acre-feet to top it off.
If you shut off all the down stream users, the reservoir would fill at a rate of 8 million acre-feet per year, a process that would take 2.5 years. Naturally, there's no real need to fill the lake
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Sure. But the green movement hates dams almost as much as it hates diesel engines modified to "roll coal".
Primarily because of the ecological damage they inflict on local wildlife.
Water is for more than power generation (Score:1)
With the drought conditions affecting a good part of the USA (little or no rain in parts of OK since last September), I would have thought that conserving water for life is more important than generating power. With careful management, you can do both but that requires a lot of joined up thinking which as we all know, governments the world over are pretty inept at.
In the meantime, do you really need to shower twice a day, do laundry with less than half a load or wash your car every Sunday?
Re: Water is for more than power generation (Score:2)
Focusing primarily on household use would be a mistake. That's not even close to a majority of water use.
https://www.usgs.gov/mission-a... [usgs.gov]
But... (Score:2)
I thought that dams were going to be one of the pillars of "Clean Energy"???
Are we going to have to build (and I shudder to think about it) nuclear power plants to provide backup power for the dams?!
We will build more nuclear power. (Re:But...) (Score:1, Informative)
We are going to build more nuclear power plants. Building them near hydroelectric dams is likely a very good idea. Nuclear power plant operators like to run them at as high of output that is safe, and do so as consistently as possible. Changing the output of a nuclear power plant is certainly possible, France does this routinely because they lack sufficient sources of hydro and natural gas generating capacity to not vary nuclear power plant output.
One problem with lowering output on a nuclear power plant
US inventory of dams (Score:5, Interesting)
The National Inventory of Dams [army.mil] lists over 90,000 dams. Note, however, that the vast majority of those will be small and made of earth. Converting those to produce electricity would be quite expensive, I would imagine. However, some states such as Virginia have started requiring all those earthen dams to be topped with concrete, since an earthen dam is obviously at quite a risk of collapse if it overflows. Maybe they can get a two-fer: as long as you're spending money to top a dam, spend a little bit more and add some hydropower. What say you, civil engineers?
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I would have thought this was quite feasible with suitable small scale generation technology. With small turbines the electricity would be converted to DC, then back to AC by an inverter that follows the grid's frequency. Similar to small scale wind turbines.
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Small scale hydro has small scale output. In cases where there are already sufficient utility connections nearby it might be worth it, otherwise it's a waste of time. The costs are much higher than you might imagine. Since water is involved, the ongoing equipment and maintenance costs can be significant.
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'a little bit more'?!
An engineered concrete cover is in NO WAY relevant to the complexity and cost of a hydropower system. Water must come from the lower dam (energy is a function of water pressure), which means a need to manage flows mechanically rather than via a spillway, introduces risks (fouling of the turbine, risks to anyone 'sucked against the intake). Turbine sizing is a function of flows, which leads to hydrologic modeling needed. The power needs transmission lines into the grid, and flow/use n
Tapping from the top is not an issue. (Score:5, Informative)
Water must come from the lower dam (energy is a function of water pressure),
Water pressure is a function of the height where the water is used, not where it is removed from the reservoir. (The weight of the water in the pipe, one PSI per 2.31 feet, raises the pressure as much as the weight of the water for an equal added distance above a lower inlet, so it's a wash.) The fluid friction of the flow through the pipe can cause some drop, but make the pipe large enough and the added length to tap the dam higher is not a big deal.
Reservoirs are normally tapped low so they can provide output even if they're only partially filled (though not so low that they constantly clog with sediment). If you don't plan to generate power if the reservoir is below a particular level, you don't need to tap it below that level. If your new cap goes down to that level, you're fine.
Even if it doesn't, you can easily get another 20 feet or more by building your plumbing to handle up to one atmosphere of negative pressure and running it as a siphon. That might even be run over the top of the dam (as is done on a small scale for some irrigation routing). You might need a vacuum pump (i.e. a water pump and a venturi) to get it started initially or after it has "sucked out" when the level got too low or whatever, but you only need a very small one and only need it for a short time.
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Remote operations will help (Score:2)
A small dam would have trouble paying for the operators in the old days. But now remote control is much more practical so every little dam would not need 4 operators ( one per shift) to watch over it.
A lot of the papermill dams on the Wisconsin River had small powerhouses built in. So the idea has been around a long time. It was a matter of economics, accountants always prefer one big whatever to several small ones.
Re:Remote operations will help (Score:5, Interesting)
A small dam would have trouble paying for the operators in the old days. But now remote control is much more practical so every little dam would not need 4 operators ( one per shift) to watch over it.
Until you end up involved in - or collateral damage in - a war (as Germany, Ukraine, and Russia have all found out). If you're remote-controlling infrastructure you need serious communication security and redundancy.
Remote controlling a power dam comes with an extra risk compared to remote controlling a wind farm, too. If the attack goes beyond denial-of-service into infrastructure sabotage, even a small dam might be converted into a weapon of mass destruction aimed at the downstream personnel and facilities. Screwing around with the water release can cause flooding, or even dam breakage and MASSIVE wave flooding. (About the worst you can do with a wind farm is grid instability, power outages, and just maybe, if the automation is buggy enough, set a mill on fire and start a grass fire.)
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We are talking small low head dams here, not Hoover.
As an example,
http://www.wvic.com/Content/Hy... [wvic.com]
I grew up near the Wisconsin River, which is why this is what I think of.
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Screwing around with the water release can cause flooding, or even dam breakage and MASSIVE wave flooding.
I'm very sorry but I'm not convinced that the risk is anything like as dreadful as you suggest. It is small dams that we are discussing here. A large dam can presumably afford the expense of operators.
A few miles from me as a stately home with a large ornamental lake maintained by a dam. I would guess that it has been there for about 200 years. It is about 90 metres wide and perhaps 10 metres high. I get the impression that this is precisely the sort of modest dam which is being considered here.
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Doesn't sound like a game changing factor (Score:3)
Currently hydroelectric power produces 6.3% of US electricity [wikipedia.org]. If the current capacity of 101GW is increased to 150GW (per summary), that will supply, what, an extra 3% of the US's electricity needs. That's nice to have, but won't change much of anything in the big picture.
However, there's one way in which dams COULD be a much bigger factor, and that's energy storage. Most dams are limited by the natural water flow into the dam, which is relatively low. If you empty the dam today to provide maximum power now, you won't have any water with which to generate power tomorrow. But what if you install a bidirectional pump? When you have excess solar energy during the day, you could pump water up to the reservoir. In the evening when there's no solar energy, you could release the same water to regenerate electricity. The same volume of water could be used over and over to generate electricity on different days. Or from a different perspective, you could have pumped hydroelectric storage using much of the infrastructure that already exists.
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Pumped hydro is most of the energy storage on the grid now, but that's mostly because it's been efficient and reliable for a long time, while batteries as good or better are only recently developed and starting to be deployed.
Pumped hydro efficiency is >85%. But batteries can be far better. Raw lithium cells are >95% (or far better, depending on the detailed chemistry) as are some other sorts, and total system round trip can be not all that much worse.
There's lots of other tradeoffs: Water is bette
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Thing with pumped storage is that you need the water to pump. Thinking about the 2 dams by me, there's not really any water below them to pump back up.
Ideally would be 2 or more large large bodies of water, one above the other so that the water can be cycled. Many of the dams here, below the dam, the water runs down the river till the next dam or the ocean.
For scale: (Score:5, Informative)
In 2016, a U.S. Department of Energy study forecast that hydropower in the United States could expand from its current capacity of 101 gigawatts to nearly 150 gigawatts by 2050
That's a 49 GW increase over ~30 years. 49GW is plenty but for scale, 21GW of wind power [eia.gov] came online last year alone with 12GW scheduled to come online this year [eia.gov].
Don't get me wrong, this is nice and all but it seems like we would be better off removing some of those unpowered dams since they cost money to maintain and have ecological impacts.
Dams KILL (Score:2)
Re: Dams KILL (Score:1)
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Re: Dams KILL (Score:2)
Failures of hydroelectric dams, or all dams?
Re: dam dangers (Score:2)
"Dam failures have killed more people than any other power source" is nonsense. Dam failure losses are dwarfed by the mortality and morbidity caused globally by coal and petroleum energy.
The trouble is paying for it (Score:5, Insightful)
Without major changes in how and who we vote for we're just going to let our electric grid collapse and if your upper middle class go buy a generator solar and batteries and leave everyone else and can't afford those screwed. Every year we'll just have around 100 people or more who die of heat stroke or freezing to death depending on the region and that'll be that and we'll just accept it as the way things are. Like a third world country
Rich teachers (Score:4, Interesting)
There's just one problem with the "tax the rich people more to pay for everything anybody wants" strategy - not NEARLY enough rich people.
Suppose you go all communist dictator and seize everything futon a millionaire in the city. Just take everything they have. That million dollars is enough to give 25 CENTS to everyone in the city of four million. Twenty five cents.
I infrastructure, you say? A new freeway costs $14 million *per mile*. If you slaughter fourteen rich families, Lenin style, you can build ONE MILE of freeway.
Maybe you don't need freeway today. New Construction Undivided 4 Lane Rural averages $3.6 million / mile. So just slaughter three or four families and you've got one mile of rural road.
You may recall aoc's "tax the rich" plan that mostly. Ran out of steam when it was repeatedly pointed out that the definition of "rich" needed includes the salaries of a teacher and firefighter. That's where you have to go, because there are a million people like teachers, firefighters, and car mechanics for every one George Soros, Donald Trump, Theresa Kerry, or Al Gore.
So you're only thinking about the wealth (Score:5, Insightful)
You're also missing the huge thing that was the entire point of my post. They are actively preventing the rest of us from building out human civilization. That's what austerity means. If for example we were to build new cities their property values would decline. If we were to build out wind and solar the value of their oil assets would decline. Their wealth and power is based entirely on scarcity of resources. It shouldn't be a surprise that they would actively take measures to ensure that those resources remain scarce.
It's difficult for the Gen xers and baby boomers on this forum to understand that because we went through the
But in actuality the super rich rather than look for radical changes want to protect what they already have the same way a king or a queen would take measures to protect their position. It's a fundamentally conservative position taken to its extreme because of the extreme power that they have
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If you were a gen xered or a baby boomer you made out really well. And so you expect that trend to continue.
I never expected it to. I wanted it to, but always had little hope. Greed ironically gets in the way of progress leading to more growth and more profit.
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If you want to play Santa Claus you're going to half to hit all those "millionaires" who saved up for retirement, because there are only a few dozen people like Al Gore or Theresa Heinz Kerry. If you take everything from the Gores and the Kerrys that doesn't even get you enough money to build a road from Gore's house to Kerry's house.
You HAVE to define "rich" as including anyone who doesn't love hang to mouth, anyone who saves.
Damns Block Fish (Score:1)
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Many species of fish don't migrate to spawn. They are content to live out their entire life cycle in one lake or region of river or stream. These fish don't care whether there is a dam upstream or downstream as long as there is sufficient water flow. The ecosystems and predator species will change to accommodate the change in resident fish species. But that's not always bad.
For migratory species, there are hatcheries. Back when we began building dams in this region of the country, it was understood that we
Where I was born (Score:4, Informative)
Where I was born, they build a lot of canals to power a very large mill complex, then it was switched to coal.
It would be nice for the City to start useing these canals for power once again. Right now they are only used to "look pretty". In fact, one canal was filled in years ago, glad they only stopped at one.
Great idea but... (Score:2)
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Y'all so serious (Score:2)
Dam nerds small hydropower for fun and profit! (Score:3)
Antique hydropower, machine tool restoration and custom machining/fab Slashdotters will enjoy this site. So may engineers who appreciate simple reliable elegant design.
http://frenchriverland.com/ [frenchriverland.com]
Small hydropower was and remains viable and this crew do epic machinery and equipment rescues and overhauls to keep dams that are often over 100 years old productive.
Here's their machine shop:
http://frenchriverland.com/mac... [frenchriverland.com]