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Harvesting Power When Freshwater Meets Salty
ckwu writes "As a way to generate renewable electricity, researchers have designed methods that harvest the energy released when fresh and saline water mix, such as when a river meets the sea. One such method is called pressure-retarded osmosis, where two streams of water, one saline and one fresh, meet in a cell divided by a semipermeable membrane. Osmosis drives the freshwater across the membrane to the saltier side, increasing the pressure in the saline solution. The system keeps this salty water pressurized and then releases the pressure to spin a turbine to generate electricity. Now a team at Yale University has created a prototype device that increases the power output of pressure-retarded osmosis by an order of magnitude. At a full-scale facility, the estimated cost of the electricity generated by such a system could be 20 to 30 cents per kWh, approaching the cost of other conventional renewable energy technologies."
How well does it scale?
Renewable is going nowhere until they're at parity.
No amount of greenwashing and tree hugging circlejerking will change the fundamental economics of this.
instead of 'pressure-retarded' should have read 'pressure challenged'
The energy density of this system is crap, plus it has all the problems of water fouling and so maintenance will be a pain. IMO, we should focus our efforts on developing cheap organic photovoltaics, and then paving the desert with them. We need more government funding injected into fundamental materials research. Disclaimer: although I don't pursue this line of research I am a researcher!
It requires saline that is MUCH more concentrated than seawater... So you need to somehow concentrate the saltwater before using it.
Although this might allow for some rather unconventional solar power projects - feeding brine from salt concentration ponds might be workable here.
retrorocket.o not found, launch anyway?
Renewable is going nowhere until they're at parity.
No amount of greenwashing and tree hugging circlejerking will change the fundamental economics of this.
And in in a few years when demand outstrips supply yet again, the Europeans, Chinese, and every other country on Earth who actually developed these "tree hugging" energy sources will look down smuggly (rightfully so!) at us for our short sightedness.
And in the meantime, our economy will be severely hampered because of the inevitable higher costs of energy with plenty of outcry from the ingnorant masses of "Drill here; drill now!" or some such.
Right now, as long as oil stays above $80/barrel, the multinatinal oil firms are currently drilling in VERY deep water because that's where all the new oil is currently. After all of that is used up, there's no place to go for oil after that.
But beleive what you want. Those who know and are capable of anticipating would is probably going to happen in several years will plan accordingly.
I plan on buying a nice big wind powered (sail boat) with the results of my planning and live in the Carribean.
At a full-scale facility...
So, we're guessing about imagined economies of scale that may or may not, hypothetically speaking, materialize, in the best-case scenario of a fully-developed, mature technology, probably some decades hence.
...the estimated cost of the electricity generated by such a system could be 20 to 30 cents per kWh...
Our wild-assed guess ranges over a factor of 1.5 anyway.
...approaching the cost of other conventional renewable energy technologies.
"Approaching", in this instance, meaning "costing twice as much as" pholtovoltaic systems, which already sit at the expensive end of the renewable spectrum.
~Idarubicin
Where salt meets fresh is often an estuary. These are unique and productive habitats. Even traditional political opponents have come together to save these environments in certain cases--the green coalition from the Democrats and duck-hunting and fishing Republicans don't want these places ruined.
Tread lightly on this. The loss may be greater than what's gained.
It's worth noting that this would have something most other renewables (solar, wind, ... ) lack - a power output that is more or less constant day and night.
"That's either incredibly asinine or the most brilliant troll I've ever read. Not sure which." -Anonymous Coward
Also, my (mostly) hydropower-sourced electricity here in Seattle is billed at 4.75 cents per kWh. :)
And how are the Salmon fishermen doing? (That was rhetorical: google "damns salmon pacific northwest fishermen" and have a read.) Wild Salmon (farmed salmon is shit: taste, "greeness" - it takes more pounds of wild caught fish than one pound of farmed salmon!) prices have increased significantly where I live.
My point is that ALL energy sources have some sort of environmental impact and why it is of utmost importance to have a portfolio of different sources.
At a full-scale facility, the estimated cost of the electricity generated by such a system could be 20 to 30 cents per kWh, approaching the cost of other conventional renewable energy technologies."
20-30 cents per kWh? I currently pay a little more than 8 cents per kWh - which is pretty typical in the U.S., outside of California, Florida, Hawaii, and the NE states.
Unless maybe we stop subsidizing fossil fuels?
Another poster mentions that the subsidies were for exploration and drilling. I'll add that these subsidies were put into effect when oil prices were very low and it just wasn't profitable to explore for more oil, and the government wanted to increase production in the Gulf of Mexico. So at the time the subsidies made sense. The problem is that the subsidies had no sunset provision, for example phasing out as oil prices rise and exploration becomes profitable once more.
... Oil and natural gas companies posted a 7.3 percent profit margin ... Those figures translate to relatively unexceptional earnings overall according to experts, especially given the size of the industry as a whole and the high cost associated with energy exploration and production. Over the past five years, average net income in the oil and gas industry has averaged about 8 cents for every dollar of sales"
So other interesting info:
"Between 2007 and 2012, the oil and gas industry paid an effective tax rate of almost 45 percent
http://www.usnews.com/news/articles/2013/04/24/is-the-oil-industry-really-getting-a-sweet-deal-on-taxes
If not: problem! Lose lose.
Since we're melting the whole continent down there, let's ring the whole place with these. That should provide the whole world with power until the process is over in a hundred years or so.
The original post:
You should note that, despite what many believe, we don't really "subsidize" fossil fuels to any major degree
The response:
Bullshit: [with references]
Is this an example of an industry shill?
I've been turning my attention to sock puppets and industry shills lately, the first question being: how can we tell the sock puppets from the regular folk?
Here is a well-formulated partisan post which is completely contrary to conventional wisdom, and is contrary to facts supported by references and evidence. It is trivially refuted by easily-found references. I expect it was "modded up" based on clarity and construction. It certainly *seems* like an informativie position by an expert in the field.
An actual expert in the field would not expect to gain esteem by posting something so easily refuted (they would expect it to be modded down immediately). I'm left to wonder what the original posted hopes to gain.
Any ideas?
The only thing they will do is to remove zones of brackish water from the environment, that are usually highly prized by greenies as having high biodiversity and such stuff. Of course this is all swept to the wayside once you can make "green energy" out of all this green stuff. You'll even find conspiracy theories thrown out by eco-nuts blaming "big oil" for preventing such "innovative alternative technology" from coming to market. If that should happen, very soon they will have an epiphany, realize that in fact those osmotic power plants destroy important ecological niches ... and by this point, of course, osmotic power plants are run by "big energy" without any respect for the environment. And of course, everybody in the green movement has always been against such a stupid idea.
How far fetched is this scenario ... look no farther than bio-ethanol.
If fossil fuels paid the true cost, according to the methods described by Adam Smith, the Father of Capitalism, which include the removal of mercantilist tax subsidies such as cheap extraction leases and no cost for pollution, then it might be competitive.
But we have artificial trade barriers in the use of subsidies and exemptions for fossil fuels that drive down the cost of fossil fuels. Things like free naval shipping lane protection by the US navy and air force given to China without cost.
Fix the source problem first.
-- Tigger warning: This post may contain tiggers! --
As per the subject, What makes it better than hydro electricity? Hydro is great, is clean, is renewal; really the only downside the ecological destruction associated with damming up the rivers.
I speculate that this new solution is going to have all the same issues as hydro does, at scale. If not, why not? I see a 'membrane' across the mouth of the river, i see turbines, I see "environmentalists protesting that the fish hatchery is being disrupted..."
"I use salt from the sea to charge special batteries that I've made."
I want to delete my account but Slashdot doesn't allow it.
Another application for the energy produced by such a plant could be to power a desalination process.
So you take 1000 litres of non-potable water flowing out of some river mouth. It could be downstream from some city and, potentially, dirty as hell. Run it through one of these PRO plants and generate the energy (electrical or pressure) to power a seawater desalination plant. The brine from the desal plant can then be back-fed into the PRO plant to increase/sustain output.
So what if you only get 100 litres of potable water, or even just 10, as output. If you have megalitres (or gigalitres) of water flowing out the river, just scale up. One of the biggest downsides to desal plants is their electricity usage. It should be possible to design a PRO+desal plant that is totally off-grid. ...and as a previous poster has said, the plant runs 24/7.
Too late, that started in earnest in 2009.
So far, Obama has handed over $14 billion of your money and mine to "alternative energy" companies. Oil companies, like every all other companies, don't pay taxes on profits they don't make because they had expenses to pay. That's the majority of the "subsidies" the morons complain about - not being taxed on non-existent earnings. The solar and wind companies, on the other hand, get taxpayer cash delivered to them, often just before the CEO closes the company and retires with a wad of your money. It's gotten so bad that last year, most wind subsidies went to build windmills placed in locations with significantly below average wind. You're supposed to put windmills on hilltops, where it's windy. It makes no sense to put a windmill in a valley - unless you're building the windmill just to collect the government kickback, with no intention of producing usable electric power.
The preferred term is pressure-learning-disabled osmosis.
I would agree, if those things could be labeled "tax deductions" as they are clearly not. You can call them tax policy I suppose. Tax deductions are only useful to offset profits -- you never make a profit, all the tax deductions in the the world do you no good.
Wow that's an impressive level of cluelessness.
Most of Alaska's government revenue is paid by oil companies. Individuals pay no tax in Alaska, but rather get a check from the oil fund. So not only does BP pay the state of Alaska, that payment ends up as cash in the hands of residents (along with also paying for all roads, police service, etc.)
The facts in your post? The fact that you either don't know how to read a financial report or don't know what "oil and gas production tax" is?
BP claims the oil is free, a gift by the State of Alaska. That's a fact. Prove it wrong. Should be easy, if it's so wrong. But no, you just attack the messenger. Have you ever even been to Alaska?
Learn to love Alaska
The first link in Google for "BP annual report" will show exactly what BP claims. See all those millions for oil and gas production tax? That's some of the money they are paying the government for the privilege of extracting the oil. See the other millions for land leases?
You are claiming that someone at BP, somewhere, some time, said something different. You're claiming they said that, feel free to back up your claim. You think I should prove that at no time in history did anyone at BP say anything that you could have misconstrued that way? If you want to play "prove the negative", okay - You posted on Slashdot that you enjoy humping large dogs. Prove you never said that.
Back in middle school I heard that lasers were 8000x brighter than the sun, so I made these magnificent plans to acquire a laser and a small solar cell, and then let the laser's 8000x brightness dominate the area ratio so it would yield more output than input. I was totally convinced that this would work, and that it would solve the world's energy problems. After months of dreaming I finally told my science teacher, and she said "no, that won't work" without even hesitating. Dreams crushed.
Sigh.
I've still never owned a laser, but some day I will test my theory!!!11
This process turns fresh water (a rapidly declining resource) into salt-water (an abundant resource)
The world doesn't need more salt water.
Sounds like a gay nigger faggot came up with this one!
Hydro is great, if you happen to have a gigantic dam handy holding back a huge lake before the water falls hundreds of feet. In North America, that means Hoover Dam, Niagra Falls and a couple others. For the other 99.9% of the population, you need another solution. Texas, for example, is the second largest state and I don't think there are any hydro falls anywhere in Texas. I live 120 miles from the coast and my elevation is about 60 feet. You're not going to get hydro power from the river here.
Alaskan legislators and Alaskan newspapers seem to agree that oil companies are taxed:
"Kelly, like many lawmakers, believes Alaska's tax structure discourages oil companies from finding and developing more crude. That impacts the state because Alaska depends on oil taxes, royalties and fees to fund most of state government. Even though ACES has created billions of dollars in surplus funds, Parnell, some lawmakers and business leaders worry that the tax is so high that oil companies aren't investing in new production."
http://www.alaskadispatch.com/article/20130409/fact-check-what-was-purpose-aces-oil-tax
They pay a "tax" on the free oil. The oil belongs to the State of Alaska, and the State of Alaska "gives" to to BP for free (then taxes it). You've confirmed my statement, yet continue to insist I'm wrong. I've worked for BP. I've been to the oil fields. Have you?
Learn to love Alaska
Most rivers have little to no potential or kinetic energy. If you can build a dam in a delta you'd obviously do that.
You do not need a dam to harvest the kinetic energy of a river. Think of an old fashioned water wheel turned by small rivers and large streams. Or turbines submerged into a large river, as they are experimenting with in New York City.
This subject comes along once in a while. The technology is far enough for some to have actually started building these things. here is one of them:
http://www.redstack.nl/index.php?Itemid=8
So how do they arrive at the 20-30 cents/kWh? Infinite durability? This has been tried in Norway http://en.wikipedia.org/wiki/Statkraft_osmotic_power_prototype_in_Hurum with rather underwelming results, outputting 4kW (not a typo) under ideal conditions. Granted this new plant is rated as 60 times more efficient it seems like a long way from a sound investment as the upfront cost is just to high.
sigh....
He's a straight-laced by-the-book detective straight out of the academy.
He's a grizzled fisherman from the wrong side of the docks.
Freshwater and Salty - Wednesday at 7, 8 central, on CBS.
systemd is Roko's Basilisk.
This is not new
http://www.statkraft.com/energy-sources/osmotic-power/prototype/
I've been reading /. since 1995 and there seems to be "order of magnitude," 50%, or whatever, improvements on some energy technology or another every day. By now electricity should be so cheap they should be paying us to use the excess just to keep the dilithium flux capacitors or [insert fancy new techhnology buzzwords here], from superploding. But noooooo.
It reminds me of an old joke. Clem was very smart and Clyde was stupid. Clyde asked Clem why he was so smart and Clem said, "It's because I take smart pills every day." "Really," said Clyde, "can you get me some smart pills?" And Clem said "Sure, here's a bag, just eat some every day." Clyde took the bag of smart pills and ate some every day, but to no avail. Finally Clyde went to Cleam and said, "I've been eating these smart pills for a long time Clem, and I'm not any smarter, and you know what, if you weren't my friend, I'd say these smart pills taste a lot like rabbit droppings." And Clem replied, "Now you are getting smart Clyde."
If I hadn't been reading Slashdot for so long, I'd say it sounds a lot like just another bottle of energy snake oil.
Another method to diminish the amount of fresh water - we have far too much of that useless fluid.
If it's being taxed, it is not free. This is a very simple concept.
And it is immaterial if he's been to an oil field or not - just because you've seen an oil derrick pumping product from the ground doesn't mean you know any more about how this works than he does, and it's ridiculous to say so. BP had to win the oil and gas lease in order to start production to begin with, as quoted from your own State's web site.
You're a fucking idiot.
Hmm, a nifty idea, but how is this better or more cost effective than building a dam?
The area around Bonneville Dam has an elevation of around 600-1,600 feet. Bonneville Dam itself is 197 feet high.
Since the land around it is about 1,000 feet elevation, the water is easily contained.
> but elevation and distance from the ocean are only a couple of values that matter
Elevation controls. If the elevation isn't high enough, you can't build a high dam, period.
Filling a 197 foot reservoir in central Texas would require flooding the gulf coast up through the entire eastern seaboard, north to New York city.
Why? Starting at 60 feet, if you build the dam up 197 feet, when full the surface of the water would be at 60+197 = 257 feet.
It would spread in every direction until it encountered an obstacle 257 feet high. Spreading through Louisiana and Alabama and along the coast, the first unbroken obstacle 257 feet high is the Appalachians.
this is a good idea. ..oh .. wait ...
now we can use the wasting of fresh water into the ocean to rescue
some fresh-water, by using the generated electricity to pump the fresh water back to
the mountains they spring from
Thank you for the well-reasoned response.
I'm now of the opinion that this isn't a sock-puppet post. I've reviewed the user's history and it doesn't seem especially partisan and it doesn't have other clues, such as infrequent posts or recent creation.
I'm still on the lookout for sock-puppetry. This is made more difficult by the automatic backlash from many readers, which you don't seem to have. I'm still wondering how to detect false opinions and other manipulation of the board - if you have any ideas, please let me know.
Estuaries tend to have interesting ecosystems associated with them--Everglades, mangroves, etc that are also important in hurricane protection, among other things. What's the likely environmental impact of building these sorts of power plants?
I agree. The brine can be stored in a big pond at night, then drawn down during the day: It doesn't have to be constant output.
Why are you arguing with me about BP's words? BP is the one that says it's "free" oil that's then taxed. You are shooting the messenger. Why? Someone else posted BP's words to argue with me, but the words agreed with what I've been saying.
Learn to love Alaska