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Energy From Raindrops

ScuttleMonkey posted more than 6 years ago | from the don't-stop-the-rain dept.

Power 144

conlaw writes to share that according to Discovery.com scientists have found a way to extract energy from rain. A new technique could utilize piezoelectric principles of a special kind of plastic to generate power from falling water in rainstorms or even commercial air conditioners. "The method relies on a plastic called PVDF (for polyvinylidene difluoride), which is used in a range of products from pipes, films, and wire insulators to high-end paints for metal. PVDF has the unusual property of piezoelectricity, which means it can produce a charge when it's mechanically deformed."

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I can't believe... (0, Interesting)

Anonymous Coward | more than 6 years ago | (#22359400)

we learned how to extract power from raindrops, and still no one is extracting power from gyms :P

Re:I can't believe... (4, Interesting)

32771 (906153) | more than 6 years ago | (#22359460)

You are quite wrong, treadmills have been used in the past to power all sorts of things. Here is an example:

http://www.uic.edu/aa/college/gallery400/notions/histories.htm [uic.edu]

"The hospital of Bicêtre, France boasts a prodigiously deep well underneath, dating from 1735. The horizontal wheel that pumped the water was turned
  initially by twelve horses, then, starting in 1781, by 72 men, taking shifts on a 24 hr day. These workers were eventually replaced by epileptic
  patients and "madmen" in residence at the hospital."

I would also challenge the notion that fluorinated plastics can be produced energy efficiently enough to actually produce an energy surplus by collecting raindrops. I might be wrong
though, but out of laziness I'll leave the proof to somebody else.

Re:I can't believe... (1)

ralph90009 (1088159) | more than 6 years ago | (#22360436)

This isn't the first I've heard of using piezoelectrics to collect power from rainwater. The last one was actually using a separate piezo element under a plastic sheet. Maybe the two research teams aught to put their heads together and try to double their yeild? P.S. Even if it's not a massive surplus, every little bit helps!

Re:I can't believe... (1)

jyjjy (1236308) | more than 6 years ago | (#22361834)

patients and "madmen" in residence at the hospital."

Wasn't this kind of thing shown in the movie Midnight Express?

who is john galt? (1)

superwiz (655733) | more than 6 years ago | (#22359422)

well, that's not exactly the galt engine, but it sure smacks of that sentiment.

Re:who is john galt? (0)

Anonymous Coward | more than 6 years ago | (#22361702)

> well, that's not exactly the galt engine, but it sure smacks of that sentiment.

A source of energy, thousands of times more powerful than conventional energy, had been developed. Some folks, like Galt, wanted to use it to power the world. Other folks had other plans in mind. Remember that other project that Ferris and Stadler of the State Science Institute were working on? The "non-profit venture"? Go back and re-read the description of both the project's output, rationale for funding, and ultimate purpose...

The book was written in 1948. What source of energy had captured the minds of the public, thousands of times more powerful than conventional energy, had just been developed, and what product based on that energy, having been developed by an extremely expensive and secretive non-profit venture, and completely lacking in commercial value, had just been unveiled to the world as the means to end all war?

Read between the lines. Galt's engine has existed, in the real world, for over 60 years.

That's the subtext of the entire book -- if you have a mind, you have a choice: do you use it to build your world, or do you use it to subjugate your world?

Re:who is john galt? (1)

superwiz (655733) | more than 6 years ago | (#22362000)

The book was first published in 1957. She worked on it for 7 years. As for the claim of nuclear power being Galt's engine of the real world, I'd say it's a stretch. Having said, the perspective on the book that you point out is actually new to me. So thanks. Certainly examples can be easily constructed that show how it applies in the world of the Internet. I guess what struck me about the rain drops is the visual itself. Both Galt's engine and the the raindrops seem to draw on energy from essentially thin air. Of course, the analogy stops there.

Re:who is john galt? (2, Insightful)

kestasjk (933987) | more than 6 years ago | (#22361766)

(It's worth noting hydroelectric dams have been used for power generation for a long time now)

Ideas! (1)

buanzo (542591) | more than 6 years ago | (#22359430)

One for the floor of your shower.

Re:Ideas! (1)

32771 (906153) | more than 6 years ago | (#22359472)

That gives you a nice buzz in the morning. Bzzzt!

Re:Ideas! (2, Funny)

buanzo (542591) | more than 6 years ago | (#22359558)

Heh. How long until ThinkGeek start selling the ShowerBuzzer with Self-Power option? :P

Re:Ideas! (1)

32771 (906153) | more than 6 years ago | (#22360398)

Fits right in between Jolt Beverages and Shower Shock Caffeinated Soap.

Re:Ideas! (1)

Annymouse Cowherd (1037080) | more than 6 years ago | (#22362766)

Having the floor of your shower deform when you step on it might not be so nice...

Lincolnshire could the power house of the world... (4, Funny)

Finallyjoined!!! (1158431) | more than 6 years ago | (#22359436)

The amount of rain we get here. :-)

Re:Lincolnshire could the power house of the world (1)

mrtonic (1229970) | more than 6 years ago | (#22361912)

Oh Amen to that one!

Actually it's Inverness... (1)

Joce640k (829181) | more than 6 years ago | (#22362154)

The rainiest place in Europe is near Inverness - that's why Loch Ness is so big.

Going back to the story though, wouldn't it be much better to put this stuff in the sea? Somewhere where waves crash a lot...

Portland will be King! (1)

linzeal (197905) | more than 6 years ago | (#22359442)

Seriously though, Portland is trying to gain the title of the renewable energy capital of the United States and this would be awesome in the whole Pacific Northwest as they slowly ween themselves off the major dam systems they build up over the past 80 years.

Is this sarcasm or irony? (2, Insightful)

mangu (126918) | more than 6 years ago | (#22360964)

Portland is trying to gain the title of the renewable energy capital of the United States and this would be awesome in the whole Pacific Northwest as they slowly ween themselves off the major dam systems they build up over the past 80 years

Do you mean hydroelectric power isn't renewable? Hydro power *is* energy from raindrops, where do you think the water in the rivers came from?

Re:Is this sarcasm or irony? (1)

jdray (645332) | more than 6 years ago | (#22361510)

We in Portland are (as a group) typical of the "think green" group, wherein we want to consume energy, feel good about where it comes from, and not think too deeply about the sensibility of it all. Oddly, solar and wind energy are good (this makes me happy, because I work for a wind energy company), but hydo is bad (think of the fish!). Few people stop to think that they're all forms of solar power. Furthermore, natural gas is okay for heating your home and making hot water, not to mention the popularity of gas fireplaces here, but gas fired power generation is viewed with suspicion, and there's a huge movement to keep someone from building an LNG terminal on some fallow industrial land down river from here. And, while we have several large low-sulphur coal-fired power plants East of the Cascade mountains doing a fair job of supplying large amounts of cheap power, no one likes those at all.

So, if this plastic generates electricity when it's deformed mechanically, why not hang sheets of it cut into strips somewhere that a breeze blows regularly? Seems to me like the wind blows a lot more than the rain falls, even here in Portland.

Re:Is this sarcasm or irony? (1)

Original Replica (908688) | more than 6 years ago | (#22361570)

Do you mean hydroelectric power isn't renewable?

No, hydro is renewable, but it isn't cool. You can't have an old reliable tech and not expect treehuggers to bitch about it. I consider treehuggers a very small portion of the environmentally conscious population, treehuggers will only be happy when everyone lives in crappy mud brick communes and conserving water by only showering weekly. These are the very same people who bitch about wind farms disrupting the birds. I'm sure even solar furnace towers [wikipedia.org] will be bad once some rare bird tries to roost in the tower. The dams in the Northwest make lakes where there didn't used to be lakes (how unnatural!) and make it impossible for salmon to spawn up river. After 80 years, I think the parts of the river ecosystem that could adjust adjusted and the rest died a long time ago.

Re:Is this sarcasm or irony? (1)

dgatwood (11270) | more than 6 years ago | (#22361732)

The wind thing is pretty silly, I agree. That said...

Those folks aren't wrong about hydro being bad. Hydro power creates lakes that end up burying lots of plant matter on the floor, which then rots and gives off lots of greenhouse gasses (methane, primarily). In fact, IIRC, at least one study concluded that many hydro power plants are less green than coal power plants because of the sheer quantity of methane released by those lakes.

That's not saying that all hydro power requires creating huge lakes. You could do a small turbine even on a stream without creating any significant backup. However traditional large-scale hydro power plant designs (with dams, lakes, etc.) are anything but green, and we shouldn't kid ourselves by pretending that using hydro is saving the environment....

Re:Is this sarcasm or irony? (1)

mangu (126918) | more than 6 years ago | (#22362122)

IIRC, at least one study concluded that many hydro power plants are less green than coal power plants because of the sheer quantity of methane released by those lakes.

No, I don't think you remember quite correctly. At least, it's not "many" dams. That case you mention has been made for only one dam in the world, AFAIK [google.com] .


And do you know what would have been the simplest solution for that one? Let loggers cut the trees before the dam is filled. And burn the remaining brush, CO2 is not as bad as letting it rot to methane. I guess not even the tree huggers would object to cutting a forest that will soon be flooded.

Re:Is this sarcasm or irony? (1)

Jah-Wren Ryel (80510) | more than 6 years ago | (#22361704)

where do you think the water in the rivers came from?
Cow piss. Cow farts being the second greatest contributor to global warming, they gotta balance it out somehow.

Oblig Gene Kelly reference (1)

Alain Williams (2972) | more than 6 years ago | (#22359444)

These things don't generate much energy, but should be enough to power a perpetual tiny rendition of Gene Kelly' 1952 hit film.

Re:Oblig Gene Kelly reference (2, Funny)

4D6963 (933028) | more than 6 years ago | (#22359608)

should be enough to power a perpetual tiny rendition of Gene Kelly' 1952 hit film.

Would that be "Watching 'Singing in the rain' in the rain"? That would make a catchy song! "I'm watching Singing in the rain in the rain, I'm watching Singing in the rain in the rain, what a glorious feeling, I'm happy again!"

meh (1, Insightful)

Anonymous Coward | more than 6 years ago | (#22359468)

Or just collect the water and run it through a water mill. WTF??

Re:meh (2, Insightful)

The Second Horseman (121958) | more than 6 years ago | (#22359550)

Because with this, you can just put them on the roof! Under the solar panels! Oh . . . wait, no. On top of the solar panels! No, that won't work either . . .

Seriously, though, if it actually worked, it might be an alternative in a spot that gets enough rain / regular cloud cover to reduce the attractiveness of solar. I guess.

Re:meh (1)

mikael (484) | more than 6 years ago | (#22359632)

You have a gutter below the solar panels on the roof. This collects the rain water and funnels it down a sprinkler onto the set of piezo-electric raindrop energy generators. This water then runs off down a couple of water-wheels before being collected into storage barrels, where it is gradually released and drives a micro-miniature water turbine.

Imagine all the energy that is going to be created!!!

Re:meh (2, Insightful)

DavidTC (10147) | more than 6 years ago | (#22361120)

That's almost enough energy to hoist it up there in the first place!

Re:meh (1)

fbjon (692006) | more than 6 years ago | (#22359952)

You can put it on the south side of the roof (for north hemispherians). Add a wind turbine [windside.com] or a few, and you've covered the majority of weather conditions.

Re:meh (1)

X0563511 (793323) | more than 6 years ago | (#22361054)

Do both! Let the rain fall in a big pit lined with this, and let the water run off into a collection tank which feeds a watermill.

Re:meh (2, Interesting)

TheGavster (774657) | more than 6 years ago | (#22361846)

Collecting the water and running it through a mill only takes advantage of the drop from the roof to thr ground, where this device takes advantage of the larger drop from cloud level. That said, there's no reason that you can't line your collection pan with this stuff and still use waterwheels in downspouts. I'm also guessing that a waterwheel can do a better job of extracting energy than this plastic, so for taller buildings (closer to the cloud/farther from the ground) I can see turbines winning out.

B.J. B.J. Over there on Bass Guitar (0)

Anonymous Coward | more than 6 years ago | (#22359470)

Raindrops keep fallin' on my head
And just like the guy whose feet are too big for his bed
Nothin' seems to fit
Those raindrops are fallin' on my head, they keep fallin'

So I just did me some talkin' to the sun
And I said I didn't like the way he got things done
Sleepin' on the job
Those raindrops are fallin' on my head, they keep fallin'

But there's one thing I know
The blues they send to meet me won't defeat me
It won't be long till happiness steps up to greet me

Raindrops keep fallin' on my head
But that doesn't mean my eyes will soon be turnin' red
Cryin's not for me
'Cause I'm never gonna stop the rain by complainin'
Because I'm free
Nothin's worryin' me

[trumpet]

It won't be long till happiness steps up to greet me

Raindrops keep fallin' on my head
But that doesn't mean my eyes will soon be turnin' red
Cryin's not for me
'Cause I'm never gonna stop the rain by complainin'
Because I'm free
Nothin's worryin' me

Let's think about this for a second... (2)

SimonTheSoundMan (1012395) | more than 6 years ago | (#22359486)

Whatever happened to water wheels? We have been using them for thousands of years.

Re:Let's think about this for a second... (3, Informative)

FroBugg (24957) | more than 6 years ago | (#22359512)

We upgraded to hydroelectric dams, which provide a very significant amount of power both in the United States and worldwide. China's still working on the Three Gorges Dam, the biggest ever.

Unfortunately, the US is tapped out on hydroelectric. There really is nowhere for us to put in additional ones, and the ones we already have are often cited as concerns with regards to environmental impact and municipal water supplies.

Let's sink about this for a second... (0)

Anonymous Coward | more than 6 years ago | (#22359548)

"Unfortunately, the US is tapped out on hydroelectric."

Would that be pre or post global warming after the ocean levels have risen?

Re:Let's think about this for a second... (3, Interesting)

TheRaven64 (641858) | more than 6 years ago | (#22359918)

Hydroelectric dams are not quite as good, in theory, as power from raindrops. The sun heats up water, which evaporates and forms clouds. These then fall a long way (lose a lot of potential energy, mostly turning it into kinetic energy and losing some as heat to air resistance) and are caught in a reservoir and lose all of their kinetic energy. They then fall a bit further over a turbine, but by this time they have lost most of their energy.

Now, if you could build a completely frictionless waterwheel and put it underneath each raindrop, you would get a lot more energy than if you caught the same raindrop in a bucket and then let it drip onto the water wheel (which is effectively what a hydroelectric plant does). There are two problems with this idea. The first is that rain falls over a large area. The total energy from all of the raindrops is a lot, but the individual energy is quite small. The reason hydroelectric seems like a good idea is that, although you only capture a small fraction of the energy from each drop, water falls in to the reservoir from the surrounding hills, so you are capturing rain drops from a very wide area. Once you concentrate rain enough, your losses to friction become a lot less (try building a waterwheel that will spin when a single raindrop hits it, then try building one that will spin when you pour a bucket of water on it and see which is easier).

This piezoelectric idea is quite neat, because it allows you to capture a significant proportion of the energy from each rain drop and convert it directly into electricity (although you'll probably lose a lot transforming it into anything that you can draw a stable current from). It has the same problem that the hypothetical rain-powered water wheel had, however, and the same problem solar power has: You need a lot of surface area to get a decent amount of energy out. If we assume that it is twice the power output per unit rain of a hydroelectric plant (water falling more than twice the height, but lower efficiency power conversion. Entirely made up number, but probably within an order of magnitude) then it will need half the area of the hydroelectric plant to generate the same amount of power. Note that this isn't just the area of the reservoir, it's the total area that rain falls.

Some more back-of-an-envelope calculations:

Annual rainfall where I live is around 1-3 metres (more slightly inland than on the coast). Let's say 2m as an average. Cumulous cloud (the kind that typically causes rain) forms at 2-16km. Picking a number somewhere in the middle, let's say 8km for the average distance rain drops fall. That means, every year, two cubic metres of rain fall 8km per square metre of ground. That's 2,000 litres, which means roughly 2,000 kg. The total energy in this is calculated as mgh, so: 2,000 x 9.8 x 8,000 = 156,800,000 J.

That sounds like a big number, so let's break it down. Electricity is usually sold in kWh. One W is one J/s, so one kWh is 3,600,000J. That means this gives us 43.5kWh/year energy generation for every square metre of land we allocate for it (note: I am assuming 100% efficiency here, while I would be really surprised if it got 20% in the real world). The average household uses something in the range of 3-4MWh of electricity per year, so you would need 1,000 m^2, or roughly a 30x30m area of land per house. Assuming a more reasonable efficiency, you're looking at somewhere closer to 60x60m, which is still under an acre. Of course, you could probably combine this with solar energy, since solar power is pretty useless when it's raining and so you wouldn't need to supply the entire house's electricity with just this. If they can get efficiency to the 10-20% range, it seems feasible for a lot of uses.

Re:Let's think about this for a second... (1)

QuickFox (311231) | more than 6 years ago | (#22360022)

It sounds to me like you'd get more energy from this material by having strips of it fluttering in the wind.

Re:Let's think about this for a second... (1)

Adambomb (118938) | more than 6 years ago | (#22360328)

Why not both? Wouldnt a horizontal sheet have only a short list of vectors from which wind would cause no turbulence, so most winds would?

Re:Let's think about this for a second... (3, Informative)

Aaron Isotton (958761) | more than 6 years ago | (#22360114)

Annual rainfall where I live is around 1-3 metres (more slightly inland than on the coast). Let's say 2m as an average. Cumulous cloud (the kind that typically causes rain) forms at 2-16km. Picking a number somewhere in the middle, let's say 8km for the average distance rain drops fall. That means, every year, two cubic metres of rain fall 8km per square metre of ground. That's 2,000 litres, which means roughly 2,000 kg. The total energy in this is calculated as mgh, so: 2,000 x 9.8 x 8,000 = 156,800,000 J.


The calculation seems to be correct but the concepts don't hold.

The *potential* energy of the rain can indeed be calculated using m*g*h as you said. The piezoelectric panels convert the rain's *kinetic* energy to electricity. The kinetic energy on impact is *not* equal to the potential energy, because most of it is lost to air friction.

As others pointed out, the speed of a rain drop is around 8 m/s. This means that the kinetic energy of your 2t of water is E = mv^2 = 2000 * 64 = 128,000J. You're three orders of magnitude off.

Re:Let's think about this for a second... (1)

mindstrm (20013) | more than 6 years ago | (#22360186)

Terminal velocity for raindrops appears to be about 20mph, or about 32km/h, or about 9 m/s and that's for extremely large drops in huge storms. They would hit that after falling for about 1 second.. so all that extra altitude wouldn't seem to be helping at all.

Your calculation would the be 2000 * 9.8 = 19,200 J

http://www.shorstmeyer.com/wxfaqs/float/rdtable.html [shorstmeyer.com]

Re:Let's think about this for a second... (1)

It'sYerMam (762418) | more than 6 years ago | (#22361282)

A better idea, perhaps, would be a massive cascade of these things, angle slightly downwards, so that rain would hit, drip off, fall for about a second, hit another, drip off, etc. That distance is about 9/19.6=.45m. So for approximately each additional half meter, you are gaining another unit area.

Re:Let's think about this for a second... (1)

Hyperspite (980252) | more than 6 years ago | (#22361856)

The only reason this is better than one is because the rain that hits it has less drag force on it (D=1/2 rho Area v^2). You could cascade them so that the drops reach 8 m/s each time. That might be cool.

Re:Let's think about this for a second... (5, Informative)

ultranova (717540) | more than 6 years ago | (#22360506)

Annual rainfall where I live is around 1-3 metres (more slightly inland than on the coast). Let's say 2m as an average. Cumulous cloud (the kind that typically causes rain) forms at 2-16km. Picking a number somewhere in the middle, let's say 8km for the average distance rain drops fall. That means, every year, two cubic metres of rain fall 8km per square metre of ground. That's 2,000 litres, which means roughly 2,000 kg. The total energy in this is calculated as mgh, so: 2,000 x 9.8 x 8,000 = 156,800,000 J.

Unfortunately, this is wrong. A raindrop doesn't keep on accelerating all of these 8 kilometers; it will reach it's terminal velocity, at which point the deceleration due to air resistance exactly cancels the acceleration due to gravity. Since raindrops are small, their surface area is large compared to their mass, so I'd imagine the terminal velocity to be rather small - which is a good thing, otherwise we'd get our skulls crushed to powder by rain, but sadly means that we can't extract all that much power from a single raindrop.

Actually, I checked, and according to WonderQuest [wonderquest.com] , the average speed of a raindrop is between 2 (for small ones) to 9 (for large ones) meters per second. Since kinetic energy is mv^2, this works out to between 2000kg * 2m/s * 2m/s = 8000J (= 0.002 kWh) and 2000kg * 9m/s * 9m/s = 162 000J (= 0.045 kWh) per square meter per year.

Since the price of electricity is about 0.07 euros per kWh where I live, and a square meter of this thing would need about 22 years to produce a single kWh under optimal conditions and assuming a 100% efficient conversion, I don't think that it is a good investment.

Re:Let's think about this for a second... (2, Informative)

ultranova (717540) | more than 6 years ago | (#22360560)

Hups ! That should be 0.5*mv^2. So the above figures are twice as good as they should be - it's going to take 44 years to produce a single kWh per square meter :(.

Re:Let's think about this for a second... (1)

Dulimano (686806) | more than 6 years ago | (#22362714)

I didn't check your calculation, but if it is correct, that would mean that you need a 4800mx4800m area to permanently provide energy for one 60W lightbulb. (sqrt(60.0/0.045*365*24*2))

Re:Let's think about this for a second... (2, Interesting)

maxume (22995) | more than 6 years ago | (#22360990)

The distance that the raindrop falls is irrelevant when calculating the energy available when it hits the ground -- the velocity is what matters. You are imagining that you can capture the entirety of the potential energy that the raindrop contains before it starts falling, when in reality, you are limited to capturing the kinetic energy it contains when it lands. So if air resistance happens to slow the drop down, you are losing energy well before the drop ever gets to your system. Googling says that the terminal velocity for a drop of rain is generally less than 10 meters/second.

From velocity=acceleration*time, you can infer that the rain drop is reaching that velocity in about a second, after falling about 10 meters(OK, so it would be going slightly slower than 10 m/s and have fallen somewhat less than 10 meters, whatever). So your availability calculation should be 2000*9.8*10=196,000 J, a factor of 800 less than what you stated. So if your device is 100% efficient, my still generous estimate is that you would need 800,000 square meters, not 1000, which is more like 900 meters on a side, and more like 200 acres.

Re:Let's think about this for a second... (1)

It'sYerMam (762418) | more than 6 years ago | (#22361186)

Problem: not all of the GPE will get converted to kinetic. A raindrop is pretty small so it will, I think, have a low terminal velocity. Hence after a relatively speaking short distance, it will lose GPE to friction rather than increasing its speed.

Re:Let's think about this for a second... (0)

Anonymous Coward | more than 6 years ago | (#22362310)

Since air is not frictionless, raindrops are traveling at their terminal velocity of 20 mph or so after a few meters' drop. So your multiplication by 8000 is way off -- most of that energy is lost to friction with air.

Re:Let's think about this for a second... (0)

Anonymous Coward | more than 6 years ago | (#22361224)

Yeah but what if we took all the water flowing out of hydroelectric dams... or hell all the water flowing EVERYWHERE... through pipes... in storm drains... anywhere water flows... and use a technology like this: http://www.expressnews.ualberta.ca/article.cfm?id=5117 [ualberta.ca] ... to "exploit the natural electrokinetic properties of a liquid such as ordinary tap water".

Ohhhh... (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#22359504)

"I am such a looser. I cant do anything right and whatever I do I fail at it. What the fuck do i have to do with my life I dont know. I have no where to go. My future is totally black. I have lost all hope and faith. I am old and didnt do anything with my life. I am useless. How lucky are other that they have so much success. Why is that I was born as a looser. I cant get anything done, even simple things that others do it so easily. I am such a unlucky person on this planet. Why is that I cant get anything done. Why oh Why. I am hopeless..."

Re:Ohhhh... (0)

Anonymous Coward | more than 6 years ago | (#22359618)

Hey asshole, it's spelled "loser". Looser is the opposite of tighter. Jackass.

Our Worries Are Over (5, Funny)

hyades1 (1149581) | more than 6 years ago | (#22359510)

If they put this stuff on the floor around the urinals at my local bar, we could meet Canada's energy needs for the next hundred years.

Re:Our Worries Are Over (1)

COMICAGOGO (1055066) | more than 6 years ago | (#22359614)

I tip my hat to you sir, I was just going to post the same thing. I read the summary and thought to myself, "does this work with piss?" I am sorry that you managed to post about it first.

Seriously, though, this could be a very revolutionary technology for areas that have a lot of rainfall and not much sun. I my area you could put rings of this stuff under the trees and power the whole place.

Re:Our Worries Are Over (1)

hyades1 (1149581) | more than 6 years ago | (#22360782)

Ah, a Left Coaster, I'm guessing. I have friends and relatives out there. Pale, stoned people who seem to have a lot more fun than me.

This does seem to offer some promise. It would take quite a while, I'm thinking, to slow the planet's rotation by making use of the kinetic energy of raindrops.

And I don't doubt you'd have beaten me to the post if I hadn't noticed just last night how nice it was to have worn waterproof winter boots to the pub.

everything produces energy (2, Insightful)

xzvf (924443) | more than 6 years ago | (#22359536)

Anything that moves can produce energy. The point is how much and at what cost to capture and reuse or store. I can solar panels on my roof for about 15K that averages about $120 a month. About a 10 year payback. A wind turbine that generates about 20% of my needs would cost 5K and have a payback of 15 years. Strapping a motion generator to myself and family to produce enough power to charge cell phones doesn't appear to ever justify the initial cost. Raindrop system.... call me when it costs the same as a shingle.

Re:everything produces energy (1)

iamhassi (659463) | more than 6 years ago | (#22360256)

"Anything that moves can produce energy. The point is how much and at what cost to capture and reuse or store."

Mod parent up. He's exactly right. I'm tired of hearing about all these hairbrained schemes to find new sources of power, only to read it costs thousands to implement and only creates a couple kilowatt an hour (if that much!), compared to just buying it at the rate of 7 to 10 cents per kWh.

That's why we don't have water wheels [wikipedia.org] on all our drain spouts because you'd never recoup the initial investment even though water wheels have been around for over a thousand years. You have to store the energy in batteries and convert it to work with a standard AC household. All of that is very expensive.

Re:everything produces energy (1)

Presence2 (240785) | more than 6 years ago | (#22360544)

ROI is not the only consideration for alternative energy. Quit asking "what's it in for me" while looking at your wallet and go visit a stream near a coal plant, or take a deep breath in a city, or look at the evening news about Iraq and ask yourself what the ROI really is. You sir, are exactly why we have these problems in the first place; cheaper is not always better.

Re:everything produces energy (1)

FooAtWFU (699187) | more than 6 years ago | (#22360564)

Anything that moves can produce energy. The point is how much and at what cost to capture and reuse or store. I can solar panels on my roof for about 15K that averages about $120 a month. About a 10 year payback.
Yeah, about that. Does that include your opportunity cost, where you could put that $15k in a very very safe FDIC-insured 4% savings account / CD / money market account, and make $50 a month off it? Then that's more of a... 18-year payback. (Longer if you can get a better return off of riskier investments. Like stocks, and bonds, and such.)

nothing produces energy (1)

mattcoz (856085) | more than 6 years ago | (#22362700)

Everything has energy, and that can be converted to electrical energy.

Definitely vapourware ... (1)

Mostly a lurker (634878) | more than 6 years ago | (#22359566)

... but whether this means it really produces power from water vapour, or is an idea they cannot implement is unclear.

Re:Definitely vapourware ... (1)

normuser (1079315) | more than 6 years ago | (#22359754)

Nonono, Water vapour [wikipedia.org] is the gas form, TFA is talking about the liquid form falling from the sky.
see Precipitation wiki [wikipedia.org] for more.

Hey I've got one too! (2, Funny)

skulgnome (1114401) | more than 6 years ago | (#22359576)

Let's build a very large vat. I mean it has to be huge. Then collect lots of rainwater in it, and stick a mechanism that changes outflow into something that can be used to spin a generator. Boom, electrical energy from rain!

Of course this is still just indirect-indirect-indirect solar power, as always. But jeez, do you have to make things so complex by default? Is this the "innovation-promoting" effect of patenting?

Re:Hey I've got one too! (1)

foxxer (630632) | more than 6 years ago | (#22359686)

I can't tell if you're being sarcastic or not, but didn't you just build a dam on a nice canyon-y river?

Re:Hey I've got one too! (1)

skulgnome (1114401) | more than 6 years ago | (#22360514)

Of course I'm not sarcastic. Would you not buy a used car from someone named "skulgnome"? Hm? Do you have something against gnomes? "Diminutive jews", I heard someone say.

The device I described is of course known as ELECTRORAINIMATOR in the civilized (i.e., non-US) world. It has been the trade secret of my family line for the past four centuries.

Re:Hey I've got one too! (1)

p4ul13 (560810) | more than 6 years ago | (#22360788)

Let's all give Foxxer a big round of applause. If there's anything that's funnier than a science joke, it's somebody explaining a science joke to everybody who already got it.

Take a bow sir!

Re:Hey I've got one too! (1)

JaredOfEuropa (526365) | more than 6 years ago | (#22361638)

Is this the "innovation-promoting" effect of patenting?
This thing captures (some of) the kinetic energy of the falling raindrops; this energy is lost in your vat.

I wonder how this material stacks up, in terms of cost and surface area per generated Wh, against a vat up on a pole with a water wheel and a generator. Hey, you can even combine the two: shingle your roof with this new material, and put a small generating turbine at the bottom of the drainpipe. Even so I doubt that you can generate significant amounts of energy from it, a solar panel + battery is a better choice if you need power off the grid. Even in overcast conditions a solar panel generates a little electricity.

Anyone did the math on this, something like average nr of drops / (s . m^2) * weight of an average raindrop * velocity of an average raindrop ^2, to get an idea of the power you can generate from falling rain.

Great! Now I need to buy another cell phone! (1)

tsjaikdus (940791) | more than 6 years ago | (#22359592)

I have one powered by a generator attached to my knee joint. One to a string vibrating in the wind outside. One to my hamster. I'm seriously running out of cell phones by now. I'm starting to feel guilty not using more of this green energy.

Energy from ... (0)

Anonymous Coward | more than 6 years ago | (#22359622)

... my arse. I can collect the power of farts and even patent the method.

creators provide unlimited supply; newclear power (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#22359638)

no gadgets required. let yOUR conscience be yOUR guide. you can be more helpful than you might have imagined. there are still some choices. if they do not suit you, consider the likely results of continuing to follow the corepirate nazi hypenosys story LIEn, whereas anything of relevance is replaced almost instantly with pr ?firm? scriptdead mindphuking propaganda or 'celebrity' trivia 'foam'. meanwhile; don't forget to get a little more oxygen on yOUR brain, & look up in the sky from time to time, starting early in the day. there's lots going on up there.

http://news.yahoo.com/s/ap/20071229/ap_on_sc/ye_climate_records;_ylt=A0WTcVgednZHP2gB9wms0NUE [yahoo.com]
http://news.yahoo.com/s/afp/20080108/ts_alt_afp/ushealthfrancemortality;_ylt=A9G_RngbRIVHsYAAfCas0NUE [yahoo.com]
http://www.nytimes.com/2007/12/31/opinion/31mon1.html?em&ex=1199336400&en=c4b5414371631707&ei=5087%0A [nytimes.com]

is it time to get real yet? A LOT of energy is being squandered in attempts to keep US in the dark. in the end (give or take a few 1000 years), the creators will prevail (world without end, etc...), as it has always been. the process of gaining yOUR release from the current hostage situation may not be what you might think it is. butt of course, most of US don't know, or care what a precarious/fatal situation we're in. for example; the insidious attempts by the felonious corepirate nazi execrable to block the suns' light, interfering with a requirement (sunlight) for us to stay healthy/alive. it's likely not good for yOUR health/memories 'else they'd be bragging about it? we're intending for the whoreabully deceptive (they'll do ANYTHING for a bit more monIE/power) felons to give up/fail even further, in attempting to control the 'weather', as well as a # of other things/events.

http://video.google.com/videosearch?hl=en&q=video+cloud+spraying [google.com]

dictator style micro management has never worked (for very long). it's an illness. tie that with life0cidal aggression & softwar gangster style bullying, & what do we have? a greed/fear/ego based recipe for disaster. meanwhile, you can help to stop the bleeding (loss of life & limb);

http://www.cnn.com/2007/POLITICS/12/28/vermont.banning.bush.ap/index.html [cnn.com]

the bleeding must be stopped before any healing can begin. jailing a couple of corepirate nazi hired goons would send a clear message to the rest of the world from US. any truthful look at the 'scorecard' would reveal that we are a society in decline/deep doo-doo, despite all of the scriptdead pr ?firm? generated drum beating & flag waving propaganda that we are constantly bombarded with. is it time to get real yet? please consider carefully ALL of yOUR other 'options'. the creators will prevail. as it has always been.

corepirate nazi execrable costs outweigh benefits
(Score:-)mynuts won, the king is a fink)
by ourselves on everyday 24/7

as there are no benefits, just more&more death/debt & disruption. fortunately there's an 'army' of light bringers, coming yOUR way. the little ones/innocents must/will be protected. after the big flash, ALL of yOUR imaginary 'borders' may blur a bit? for each of the creators' innocents harmed in any way, there is a debt that must/will be repaid by you/us, as the perpetrators/minions of unprecedented evile, will not be available. 'vote' with (what's left in) yOUR wallet, & by your behaviors. help bring an end to unprecedented evile's manifestation through yOUR owned felonious corepirate nazi glowbull warmongering execrable. some of US should consider ourselves somewhat fortunate to be among those scheduled to survive after the big flash/implementation of the creators' wwwildly popular planet/population rescue initiative/mandate. it's right in the manual, 'world without end', etc.... as we all ?know?, change is inevitable, & denying/ignoring gravity, logic, morality, etc..., is only possible, on a temporary basis. concern about the course of events that will occur should the life0cidal execrable fail to be intervened upon is in order. 'do not be dismayed' (also from the manual). however, it's ok/recommended, to not attempt to live under/accept, fauxking nazi felon greed/fear/ego based pr ?firm? scriptdead mindphuking hypenosys.

consult with/trust in yOUR creators. providing more than enough of everything for everyone (without any distracting/spiritdead personal gain motives), whilst badtolling unprecedented evile, using an unlimited supply of newclear power, since/until forever. see you there?

"If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land."

meanwhile, the life0cidal philistines continue on their path of death, debt, & disruption for most of US. gov. bush denies health care for the little ones;

http://www.cnn.com/2007/POLITICS/10/03/bush.veto/index.html [cnn.com]

whilst demanding/extorting billions to paint more targets on the bigger kids;

http://www.cnn.com/2007/POLITICS/12/12/bush.war.funding/index.html [cnn.com]

& pretending that it isn't happening here;

http://www.timesonline.co.uk/tol/news/world/us_and_americas/article3086937.ece [timesonline.co.uk]
all is not lost/forgotten/forgiven

(yOUR elected) president al gore (deciding not to wait for the much anticipated 'lonesome al answers yOUR questions' interview here on /.) continues to attempt to shed some light on yOUR foibles. talk about reverse polarity;

http://www.timesonline.co.uk/tol/news/environment/article3046116.ece [timesonline.co.uk]

why rain? (0)

Anonymous Coward | more than 6 years ago | (#22359660)

sew it into flags and power your house by being patriotic. make it into windows on skyscrapers and power them from wind turbulance. pave the streets with it and recoup energy from vehicles passing by. replace windmills that kill birds with fluttering strips of it in pretty colors. make strips of it that look like kelp and line tidal areas and river bottoms with it to help the fish and generate power at the same time. there are lots better possibilities than waiting for it to rain.

Re:why rain? (2, Interesting)

jrmcferren (935335) | more than 6 years ago | (#22359992)

Why not put into floors of buildings, that way the building get energy from people walking around. Also put in in sidewalks that way the same principal would work for people walking on the street.

Re:why rain? (1)

DavidTC (10147) | more than 6 years ago | (#22361190)

Actually, considering that large buildings are designed to sway, it would indeed be possible to generate power at the top by putting a heavy weight there and generating power as it moved with respect to the building.

Of course, the problem is that a weight that could generate a meaningful amount of power would unbalance the building as it slide from side to side.

Let's do the math on this one (4, Informative)

Ancient_Hacker (751168) | more than 6 years ago | (#22359688)

Hmm, raindrops... Why didn't someone think of this before? For a good reason:

  • Let's be generous and assume it's raining all the time.
  • And it's a real gully-washer, say an inch an hour.
  • And let's be really generous and assume this gadget captures 50% of the energy of falling water.
  • And each raindrop is at maximum terminal velocity, about 10MPH.
  • So that's about 700000 gallons of water per day per acre falling at 10MPH.
  • Which works out about 6 million pounds per acre per day at 10MPH.
  • Which is about 100 million foot-pounds per day per acre.
  • But that's only 1157 foot-pounds per second, barely 2 horsepower.
  • Roughly 750 watts at 50% efficiency.
  • Or roughly 17 milliwatts per square foot.
  • Or at ten cents a kwh, it's making almost 100 watt-hours a year, or almost a penny.

Re:Let's do the math on this one (2, Interesting)

baadger (764884) | more than 6 years ago | (#22359834)

Another way of looking at it is a 1 inch puddle of of water covering 1 acre is going to weigh approximately 100 tonnes. Falling at 10 MPH, (~4.5 m/s) and using E = 0.5mv^2 the maximum amount of kinetic energy here is approximately 1 Megajoule, which over an hour is about 280 watts.

Re:Let's do the math on this one (1)

Yetihehe (971185) | more than 6 years ago | (#22359864)

It would be better to collect all this 700 000 gallons of water with some roof installed several meters high and run water turbine with water falling down. Of course you have then 700000 gallons of water per day, which you can slightly filter and you hve drinking water. Pure profit, and no ???.

Re:Let's do the math on this one (1, Interesting)

Anonymous Coward | more than 6 years ago | (#22359926)

Wow, I'm still unsure whether you intentionally mixed the largest amount of different not easily convertible units together, or that's just the way it is when calculating with antiquated measures.

To recap: inch/hour, miles/hour, gallons/(day*acre), pounds/(acre*day), (foot*pound)/(day*acre), (foot*pound)/second, horsepower, watts, kilowatt*hour, watt*hour/day

Sure, with metric measures the list would be just as long, but you would find the same units used everywhere instead of switching between inches, miles, feet, etc.

Re:Let's do the math on this one (1)

Fizzl (209397) | more than 6 years ago | (#22361478)

Furlongs per fortnight?

But (1)

cyofee (975070) | more than 6 years ago | (#22359742)

Can it be used to run Linux?

Obvious Application (1)

Is It Obvious (1236200) | more than 6 years ago | (#22359766)

I would think the most obvious application would be as a lining for highway and rail beds, maybe even sidewalks and streets in some places. True, the variations in traffic load would determine your capacity for a C/B analysis to decide where to install the systems but if the carbon cost to manufacture the material is offset by the by the "carbon-less" power generated (discounting vehicle consumption), then why not take advantage of all that free vibration? I can see where this might be able to generate substantial amounts of power in major metropolitan areas either for direct consumer consumption or to run latent and ubiquitous powered infrastructure like traffic signals (with a grid back up, natch).

Missing something much larger? (1)

noidentity (188756) | more than 6 years ago | (#22359784)

This energy is just drops in the bucket compared to what they could get from lightning.

If at first you don't succeed... (5, Funny)

p4ul13 (560810) | more than 6 years ago | (#22359790)

...this breakthrough comes after failed attempts to generate power from roses, whiskers on kittens, bright copper kettles and warm woolen mittens.

These are a few of those researchers favorite things.

Re:If at first you don't succeed... (1)

LuxMaker (996734) | more than 6 years ago | (#22360468)

Actually the researchers were tired of singing the same old song, "Raindrops keep fallin on my head." and decided to convert their irritation to energy.

The Rain (poem) (1)

sjbe (173966) | more than 6 years ago | (#22359818)

THE RAIN
--found in Architect's Creek Hut, Westland Nat'l Park, New Zealand

It rained and rained and rained
The average fall was well maintained
And when the tracks were simple bogs,
it started raining cats & dogs

After a drought of half an hour
We had a most refreshing shower,
And then most curious thing of all,
A gently rain began to fall!

Next day but one was fairly dry
Save for one deluge from the sky
Which wetted the party to the skin
And then, at last, the rain set in.

Re:The Rain (poem) (1)

flyingfsck (986395) | more than 6 years ago | (#22361440)

Hmm, that sounds like the town I grew up in, which had an annual rainfall of 1000 mm.

Some Back of The Envelope Calculations (4, Informative)

Grond (15515) | more than 6 years ago | (#22359920)

A typical raindrop has a fall velocity of about 8 m/s [madsci.org] . Assuming a pretty healthy rainfall of 10cm (4 inches) we get 100 liters of water per square meter of land. 100 liters of water weighs 100kg, of course, and plugging that into the equation for kinetic energy gives us 6400 joules. Spread out over 2 hours, that's a whopping .89 watts per square meter.

All of that assumes 100% conversion efficiency and no losses due to standing water absorbing the impact of the drops. If the overall efficiency is, say, 50%, then you'd need something like 30 square meters to light a single compact fluorescent bulb. To generate a megawatt would require over 2 million square meters (over 500 acres).

Given that in most places it rains less often than the sun shines, this seems like an astonishingly inefficient way to generate electricity. There just isn't that much energy in rainfall.

Re:Some Back of The Envelope Calculations (2, Insightful)

noidentity (188756) | more than 6 years ago | (#22361082)

Given that in most places it rains less often than the sun shines, this seems like an astonishingly inefficient way to generate electricity.

But it's a great way to generate research money.

Pigeon Power! (1)

GIL_Dude (850471) | more than 6 years ago | (#22359974)

Just imagine: if this stuff panned out, it would not only be rain that could deform it. It could be deformed by say birds walking on it (toughen it against claws). So instead of cities trying to actively chase pigeons away (some places chase them on the ground with dogs and in the air with falcons, etc.) and the "don't feed the pigeons" signs - you would instead see "feed the pigeons right HERE." (where the special plastic is). Hopefully they get some of that rain working for them to, to wash the pigeon poop off the plastic though.

Golly, one whole microwatt? (1)

gregor-e (136142) | more than 6 years ago | (#22359986)

This is more newsworthy as an arcane Rube Goldberg method of extracting energy than as anything remotely practical. You could extract more power by implanting braces of dissimilar metals in the mouths of two teens, then forming a battery when they kiss.

More effective way to get energy. (1)

boombasticman (1232962) | more than 6 years ago | (#22360056)

Collecting the heat energy of the gasious output of your local politicians would gain much more energy for free. You only have to convince them to speak into the pipe of your selfmade heatcollector instead of the microphone.

Floors? (1)

haeger (85819) | more than 6 years ago | (#22360100)

Obviously I didn't read the article, what kind of slashdotter would I be if I did that, but what's with the focus on rain? Why not put something like this where there are lots of people moving about? Shopping malls, trainstations, airports... I'm not sure how much energy it produces but it might be enough to justify the cost. Also it would be locally produced electricity, something that's very high fashion right now.

.haeger

who tagged this vaporware? (1)

davidwr (791652) | more than 6 years ago | (#22360374)

Now, if they could get energy from steam, THAT would be vaporwa... oh wait, nevermind.

Can I make raincoats out of this? (1)

mrs clear plastic (229108) | more than 6 years ago | (#22360706)

This stuff would be great for my lighted clear plastic raincoats!

www.clearplastic.com

Already done? (1)

Edgester (105351) | more than 6 years ago | (#22360770)

Um, don't we already do this? I mean hydroelectric dams harness the power of rain as it flows from higher elevations to lower elevations.

Re:Already done? (1)

Colourspace (563895) | more than 6 years ago | (#22362852)

Well yes, but _if_ it could be done efficiently and on a sufficient scale, wouldn't it be a second bite at the cherry? First you could get the piezoelectric effect as the rain hit the 'ground' then secondly, once it had been channeled get the second bite at the dam itself? OK all it may ever be (due to those laws of thermodynamics) is an offset rather than a net gain in our energy requirements but maybe that is better than nothing? Personally I think we have the technology (which will improve in efficiency over time) but I wonder how much space it will take up on the surface of the earth forcing more and more of us to city-like urban dwellings as the rest of the natural world is taken up with the kit we need just to keep those city dwellers alive..?

Meteorelectricity (1)

Bushido Hacks (788211) | more than 6 years ago | (#22360974)

It seems quite possible to harness power from rain. We can harness the sun on a sunny day for solar energy. We can harness the wind on a windy day for wind energy. We can harness the ebb and flow of the oceans based on the moon's position for tidal energy. So why not harness the rain on a rainy day, the snow on a snowy day, or lightening on a stormy day?

Two things to consider is location and time of year. Imagine solar and wind energy powering much of Arizona during the dry season and weather energy ("Meteorelectricity") durring the monsoon season.

It sounds good in theory.

piezo and raindrop energy (1)

rnojonson (1236280) | more than 6 years ago | (#22361234)

I thought about using piezo material years ago. Weather dependent energy devices are iffy at best, wind and solar are too intermittent. Why not harness all the sidewalks, roads, dance floors where vehicle and foot traffic abound. Feet pounding the pavement seem more reliable that raindrops.

tagging (0)

Anonymous Coward | more than 6 years ago | (#22362034)

somebody tag this story "watervaporware"

Not so unusual (1)

Shadowlore (10860) | more than 6 years ago | (#22362560)

"the unusual property of piezoelectricity, which means it can produce a charge when it's mechanically deformed"

What, never had a crystal radio? Kids these days. Piezoelectricity isn't so unusual. You can go buy many products using it. Even at outfitters (read: outdoors and camping stores) you'll find plenty of devices using piezoelectricity. Given that we've known about it from the late 1800's that isn't unusual either. Some sugars, bones (let them dry first), ceramics, and many crystals are piezoelectrical. Oh and get this we can reverse it. Maybe we can use it to make ... microphones and speakers. Oh wait, been there done that. Or use it to light natural gas/propane stoves. Oh nevermind.

A while back someone (MIT?) tried to use this precise method (and material IIRC) to make power from floors at subway stations.

I could go on, but perhaps you should try Wikipedia. If they don't already have a nice article on it, I'm sure one will follow fairly quickly.

Nothing unusual about either piezoelectricity or the material used in the story.
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