Submitted via IRC for AndyTheAbsurd
Clean energy and clean water are among the major challenges for sustainable development especially in emerging countries. But traditional approaches to electricity generation consume huge amounts of water. In the US and Europe about 50% of water withdrawals are for energy production.
Similarly, producing water for humans via desalination in countries with water scarcity is a huge consumer of energy. It's estimated that in Arab countries around 15% of electricity production is used to produce drinking water.
Now, researchers believe they have found a way to combine these actions in a single device.
Existing state-of-the-art solar panels face physical limits on the amount of sunlight they can actually turn into electricity. Normally about 10-20% of the sun that hits the panel becomes power. The rest of this heat is considered as waste.
In this experiment, the scientists designed a three stage membrane distillation unit and attached it to the back of the photovoltaic (PV) panel.
The membrane essentially evaporates seawater at relatively low temperatures. The researchers were able to produce three times more water than conventional solar stills while also generating electricity with an efficiency greater than 11%. This meant the device was generating nine times more power than had been achieved in previously published research.
"The waste heat from PV panels has really been ignored, no one has thought about it as a resource," said lead author Prof Peng Wang from King Abdullah University of Science and Technology in Saudi Arabia.
"We use the heat to generate water vapour that gets transported across the membrane and then it condenses on the other side."
Source: https://www.bbc.com/news/science-environment-48910569
(Score: 1) by Sulla on Friday July 12 2019, @04:44PM (6 children)
Also describes nuclear. Can we compare scale of production and cost of getting tech to market?
Ceterum censeo Sinae esse delendam
(Score: 5, Insightful) by ikanreed on Friday July 12 2019, @05:33PM
As someone who 100% believes in the importance of nuclear and thinks the empirical evidence doesn't match the vastly overstated image of its risks: this tech is cheaper to implement in small scale, even with R&D costs. Probably by an order of magnitude.
As you approach large scale, the problems of renewable vs nuclear become highly situationally specific, where are you feeding the hot water, are you putting the plant in a densely populated area? What's the sunlight like? Are water sources in the area already adequate? If not, what's cooling the plant? Where's the nuclear waste going?
And it's not that I think these are unaswerable questions, I just think we're a society that has gotten used to not answering the question and taking the cop-out of using more fossil fuels.
(Score: 3, Touché) by DannyB on Friday July 12 2019, @09:46PM (4 children)
Solar is the ultimate form of nuclear power.
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(Score: 3, Touché) by PinkyGigglebrain on Friday July 12 2019, @10:09PM (3 children)
how can it be the "ultimate form" if it doesn't work 24/7/365 anywhere you want it?
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 0) by Anonymous Coward on Saturday July 13 2019, @05:14PM
it's your fault. you're in the wrong place.
contrary to regular belief the sun shines 24 hours.
seems this is the next paradigm shift we have to inflict on humankind after already stressing them by removing the earth as the center of the universe... ^_^
(Score: 2) by Pav on Saturday July 13 2019, @10:43PM
Combined with hyroelectric storage it IS the ultimate form... and despite having a right wing pro coal government my nation (Australia, the driest and flattest continent) is moving away from coal and towards hydroelectric storage paired with wind and solar. It's actually the privatised energy market that is forcing this move. They're turning all the old hydroelectric generating capacity (eg. the 3.7GW Snowwy Mountain Scheme [wikipedia.org], the Wyvenhoe Dam near where I'm living now etc...) into pumped storage. In the south they're pairing the sea cliffs with salt water hydro, and in the north (at Kidston [youtube.com], near the town where I grew up) they're trialing using an old open-cut mine pit as a pumped hydro reservoir. This is interesting because pits all over the country regularly fill with water anyway... it's a problem for mining.
If pumped hydro storage (the storage answer to completely replacing coal with renewables) is feasable at scale in the flattest and driest continent, then it's feasable in much of the world.
(Score: 2) by DannyB on Monday July 15 2019, @01:19PM
Combined with an electrical distribution grid, storage, and in aggregate, at scale, it would be ultimate.
The sun is always shining somewhere.
The wind is always blowing somewhere.
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(Score: 3, Interesting) by martyb on Friday July 12 2019, @04:51PM (1 child)
They used a strictly saline solution to test their device. In my experience, sea water is much more than just saline... other salts (calcium chloride, potassium chloride, etc.) As well as all kinds of organic matter and other "stuff" in suspension. Then take a look at how long the test device took to clean!
Sure, these are a matter of engineering, but the lack of mention of these other contaminants leads me to wonder if these may be too much to overcome.
Wit is intellect, dancing.
(Score: 4, Insightful) by Thexalon on Friday July 12 2019, @07:21PM
This article is pretty clearly in the genre of "Investors, please fund our startup", so I'm not going to expect a ton of honesty here.
For example, I know they aren't the first to attempt a method of solar-powered desalination: Apparently, the simplest and most primitive version of this idea was in use by the Incas centuries ago, and most survivalists teach solar still methods using a plastic sheet and something to hold the water in. Further, I'm unclear how the problems of water purification are linked in this way: They just said 50% of water draw was for energy "production" (probably including fracking and the like) which means switching the method of energy production, or reducing energy use, would make far more of a difference than the 15% power draw described for water purification.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 3, Informative) by takyon on Friday July 12 2019, @04:56PM (5 children)
Other panels have efficiencies (for electrical generation) above 30-40% [wikipedia.org]. Is it possible to harness waste heat from those for desalination, or is the "total efficiency" of this device greater? Is the electricity used in the desalination process or intended to be transmitted elsewhere?
Where are the graphene filters for desalination?
Offshore barge?
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1) by fustakrakich on Friday July 12 2019, @07:26PM (4 children)
Make it really large and just collect the desalinated water that falls from the sky for free, after all, it is solar powered, and a simple container should be easier and cheaper to build than all those fancy panels, pumps, and filters. When you're mobile you can follow the storm.
La politica e i criminali sono la stessa cosa..
(Score: 2) by takyon on Friday July 12 2019, @07:42PM (2 children)
Even if the idea wasn't stupid:
https://en.wikipedia.org/wiki/Climate_of_Saudi_Arabia [wikipedia.org]
https://en.wikipedia.org/wiki/Climate_of_the_United_States#Overall_average(s) [wikipedia.org]
Saudia Arabia average annual precipitation = 11.1 cm (4.4 inches).
Contiguous United States = 74.2 cm (29.23 inches).
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1) by fustakrakich on Friday July 12 2019, @08:09PM (1 child)
Hey, if they can pipe oil across Alaska, they can pipe water from a huge barge in the middle of the ocean, where it is raining. Gotta be very careful with spillage though...
La politica e i criminali sono la stessa cosa..
(Score: 2) by legont on Sunday July 14 2019, @12:51AM
Actually, the plan is to pipe water from Canada too https://en.wikipedia.org/wiki/Water_export [wikipedia.org]
No need for fancy tech at all.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by DannyB on Friday July 12 2019, @09:50PM
In some places, it's not such a stupid idea.
Solar PV is used in places that do get rain. It might not be a bad thing if those panels could simply collect the rain water.
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(Score: 4, Insightful) by Nuke on Friday July 12 2019, @07:31PM (1 child)
As a power station engineer I'm at a loss to know what I am supposed to have done with 50% of Europe's water. Riverside power stations do take in a lot of water for cooling, but almost all of it goes back into the river again, just a bit warmer than before. Power stations by the sea use sea water in the same way.
(Score: 1, Interesting) by Anonymous Coward on Friday July 12 2019, @08:04PM
They presumably got their numbers from these statistics [usgs.gov] published by the US government, and then they are (possibly deliberately) conflating two very different terms: water withdrawals versus water consumption.
It is a withdrawal if you pump water out of a lake and then put it back 5 minutes later, but that's not consumption because the water returned is available to be used again.
Even with all the misleading, "about 50% of water withdrawals" is still stretching the truth! You only get close to that figure if you consider surface freshwater withdrawals alone and ignore all other water sources used for thermoelectric generation!
(Score: 0) by Anonymous Coward on Friday July 12 2019, @08:43PM
not sure i am ready to throwing anything with salt at my precious solar-panels.
nature has a "nasty" habit of fouling up everything and our way of designing tech isn't helping much.
i suppose once we figure out "the way of nature" our tech would be considered alive?
anyways, it seems to make sense to get "less salty" water by harnessing the power of the sun instead of trading it for dinosaur blood?
(Score: 2) by PinkyGigglebrain on Friday July 12 2019, @10:24PM
You could use the PV panels to add additional heat to the incoming water for an OTEC [wikipedia.org] based system. It would up the efficiency of the system and keep the PV panels within optimal temperature ranges.
Oh wait, I just realized the answer to my own question. Money.
never mind.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 0) by Anonymous Coward on Friday July 12 2019, @10:55PM
How about costs of such device? If we consider production, transportation, selling, does it outperform typically used devices?
We can use an energy generator on a... as I remember it was ?platinum in hydrogen? (late 1980s, quite noisy case about this invention), it's handy and portable, but so expensive in use that nuclear plant would be cheaper.
For example, in my conditions on the northern hemisphere when sunlight is not well all time and heat is rather scarce, both PV and heat collectors start to be affordable when you rob someone else to get money for them (it's called a "subvention" and is implemented by EU or government).