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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?
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?
Unless maybe we stop subsidizing fossil fuels?
I have no problem with your religion until you decide it's reason to deprive others of the truth.
He/she's making blanket statements as an industry insider would, and then applying logic from the point of view of an average consumer. So I'm pretty sure he/she's just trolling.
Renewable is going nowhere until they're at parity.
No amount of greenwashing and tree hugging circlejerking will change the fundamental economics of this.
The problem here is you're not comparing apples to apples. The 'cost' of fossil fuels doesn't include environmental cleanup that isn't necessary with renewables. It also doesn't take into account the real cost - when you take out all the tax incentives for fossil fuels, the math becomes quite different.
Also, the cost of fossil fuels will continue to go up due to environmental laws and more difficult to process sources (like tar sands), fighting unnecessary wars to secure foreign oil sources; meanwhile, while the cost of renewable technology keeps going down.
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
Also, my (mostly) hydropower-sourced electricity here in Seattle is billed at 4.75 cents per kWh. :)
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
You should note that, despite what many believe, we don't really "subsidize" fossil fuels to any major degree. The majority of the "subsidies" people whine about are just plain old tax deductions - the same ones that other businesses get. The oil companies didn't even get those deductions for a long time, and people complained when they finally got to deduct for exploration and drilling expenses in the same way normal businesses deduct for operations.
There are a few real deductions they get, though - alternative energy research, for example. And, technically, the Strategic Petroleum Reserve counts (although that's just the government buying and storing oil in case of an emergency - and counts for about 2/3 of all actual subsidies). Compared to the size of the industry, it's tiny. Overall, the "subsidies" fossil fuels get don't affect the end-user price much - maybe a half-cent per kilowatt-hour in some markets.
Compare to the various alternative energy sources, which get massive subsidies - and are still three to five times as expensive.
You should note that, despite what many believe, we don't really "subsidize" fossil fuels to any major degree. The majority of the "subsidies" people whine about are just plain old tax deductions - the same ones that other businesses get. The oil companies didn't even get those deductions for a long time, and people complained when they finally got to deduct for exploration and drilling expenses in the same way normal businesses deduct for operations.
Bullshit:
http://www.nei.org/corporatesite/media/filefolder/60_Years_of_Energy_Incentives_-_Analysis_of_Federal_Expenditures_for_Energy_Development_-_1950-2010.pdf
http://www.elistore.org/Data/products/d19_07.pdf
If not: problem! Lose lose.
Let us know when alt energy gets 10s of billions of dollars in tax deductions.
There are two types of people in the world: Those who crave closure
Also, my (mostly) hydropower-sourced electricity here in Seattle is billed at 4.75 cents per kWh. :)
So then don't build this osmosis generator in Seattle. Meanwhile, in Hawaii, where every ounce of fossil fuel is imported, electricity costs about 40 cents/kwhr. This could make a lot of sense there.
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.
Yes. And what's the cost of the oil to BP that BP pumps out of the ground in Alaska? Alaska gives it away for free, in exchange for services provided by BP (at least according to BP accounting). Yes, an outsider would comment about money changing hands, but BP's accounting indicates that the State of Alaska "gives" it billions of dollars of oil, for free.
Learn to love Alaska
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! --
The hybrids are powered by electricity generated from coal and natural gas, and will remain so for decades. Renewables are the future but decades of research and engineering are still needed. You may desperately wish otherwise but this is reality.
If you actually read the first article it states the primary source of 'subsidy' is tax credits and limits on taxation for certain circumstances. From a 60 year total of around 800 billion, 47% is for direct tax benefits., 20% is for perceived imbalanced price controls and the costs of government oversight (ie the Nuclear regulating agency: NRC), 10% is (mostly to hydroelectric plants) for construction of Dams, access to shipping ports and operations of the Dept of Interior. Which leaves grants for operations of shipping, 6 billion, and R&D expenditures, 153 billion. Thats about 3 billion a year on average of actual subsidy. That is well in line with US government subsidy of other industries... like the 3 billion insurance program for small business loans, or 3 billion for 'improving teachers', or 4 billion for insurance against milk profit margins for farmers. etc, etc http://funding-programs.idilogic.aidpage.com/
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.
Well, considering you need large profits to make large tax deductions possible, this is not likely to be a large number for quite a while yet.
I pay 44 cents per kWh, so...
The subsidy situation varies widely from country to country. Some countries do subsidize the oil price of oil to consumers, rather heavily in some cases.
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.
Most of the hybrids are powered by gasoline.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
I bet there are some sewage treatment plants pumping millions of gallons of fresh water into the sea, though.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
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?
If this statement was true, we'd still be using things like freon in our fridges and so on.
Reality is that "green" option doesn't need to be as good. It just needs to be good enough.
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.
In what way are they subsidized?
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.
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.
Another method to diminish the amount of fresh water - we have far too much of that useless fluid.
And yet we invade Oil rich nations, and then multinational oil cartels get access for pennies on the dollar. What nation have we invaded to procure cheap sunlight?
Then there is a huge infrastructure around fossil fuels; refineries that are antiques. You also have the cost of pollution due to fossil fuels like Coal being shifted to the population. Do power companies pay for the thousands each year who will get sick or die decades earlier than they otherwise would?
We need a more comprehensive word than Subsidy. And you are also forgetting all the price manipulations now that are allowed by creating a Futures Market, which more than anything means that an oil company can outbid the cost of their own oil via a few holding companies. It's increased the price and driven scarcity the same way that Futures Contracts have for grains.
>>"ad space available -- low rates!!!"
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.
More like "the government needs to put a gun to your head". Stalinist coercion is the reason R-12 died, not R-134 being "good enough". Besides which, that's a terrible example since R-134 is actually a more efficient refrigerant than R-12 was.
HBI's Law: Frequency of calling others Nazis is directly correlated with the likelihood of the accuser being Communist.
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?
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