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How much power can we expect from rainfall?

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Re: How much power can we expect from rainfall?

#71

Post by gen220 »

qchris wrote: post #40
gen220 wrote: post #22

Earlier quoted context omitted.

I have a friend who was very interested in investing in this space, and did some research. TLDR, even though the tech is probably mature enough, the economics just aren’t there for private industry yet. It’s require major state-level funding to get it off the ground at this point, IMO. Very similar to how solar used to be. First, tidal turbines are very specialized pieces of hardware (compared to wind turbines), that…

This is a fantastic summary! In the United States, I believe that the Pacific Northwest and parts of the Maine coastline were also considered, but for many of the reasons above, I don't think any of those projects really achieved critical mass for wider adoption. I'm not bullish on the future of tidal power--there may be some use case for it, but the reality of the engineering challenges associated with putting hardw…

The friend did not.

He was looking specifically to invest in Gujarat, because of family ties. However, the government decided the project wasn’t worth it and binned it. IIRC they were more interested in developing solar. I tried googling around for articles related to it, this the best I could find: https://energy.economictimes.indiatimes.com/news/renewable/i...

Australian government wasn’t super interested in developing tidal resources because of the coal special interest groups, but also because solar resources are lower hanging fruit. The UK project was very legitimate and institutionally mature, but was more of a science project for proving the technology than an investment opportunity.

Re: How much power can we expect from rainfall?

#72

Post by abdullahkhalids »

nstart wrote: post #18

I absolutely love the gist of the article: interpreting quantitative research is something most of us are fundamentally illiterate on. That's definitely how I feel about it at least. Others might feel differently. That said, how does one actual build skills in this area. It feels like the author is able to do this here because it's a research paper in an area they have knowledge in. How does one build up a general ab…

A physics undergrad degree will teach you all of these skills. I imagine, you can memorize a fairly large set of skills needed to do this in a few months, but practicing these skills to high proficiency takes a few years - which is the length of an undergrad degree.

Re: How much power can we expect from rainfall?

#73

Post by fnord123 »

Someone wrote: post #64

Before it starts falling, a rain drop of mass m has potential energy of mgh , with g earth’s constant of gravity, and h the height of the drop above ground. Let’s pick a drop height of 1 km (low for cloud cover). That would make the kinetic energy about 10⁴m (where m is the mass of the raindrop) At time of impact, potential energy is gone, and the drop has a kinetic energy of ½mv² . Taking the (high) impact speed of…

>in real life, the alternative way of not letting air take much energy from the falling water is easier to build: make larger “droplets”, and have them tailgate each other really closely (also called a waterfall)

To make this "aqua electricity" viable in the real world you would need huge bodies of water penned up and ready to be released at the appropriate time. Like the size of a lake. Pretty ridiculous.

Re: How much power can we expect from rainfall?

#74

Post by Ixio »

jerzyt wrote: post #16

I'm surprised that tidal energy is not yet a big player. The amount of potential energy is massive, and it's very reliable, unless the moon falls of its orbit.

Looks like the first tidal power plant was built in 1966 in Brittany: https://en.wikipedia.org/wiki/Rance_Tidal_Power_Station.

It was also the largest for 45 years until a bigger one opened in South Korea: https://en.wikipedia.org/wiki/Sihwa_Lake_Tidal_Power_Station.

Not sure if someone has an analysis about why those aren't more widespread ? It seems like the existing ones are pretty massive and in very specific spots, maybe smaller installations aren't cost-effective enough.

Re: How much power can we expect from rainfall?

#75

Post by PopeDotNinja »

neltnerb wrote: post #17
csours wrote: post #14

Earlier quoted context omitted.

It will never work! The collection structures will fail left and right, the surrounding soil will be saturated and cause mudslides, you'll have to evict a bunch of people and buy their land, and besides, what about the downstream farmers? They don't give a dam!

How will salmon get back up into the gutters to spawn?

Just unleash a horde of 1st level characters to go XP grinding on the salmon, and the salmon will simply respawn after a few minutes.

Re: How much power can we expect from rainfall?

#76

Post by acqq »

I have also read one estimate about how fast the water would have to fall during 40 days and 40 nights of Noah flood to cover the "highest mountain" on Earth -- apparently that speed alone would kill everything on Earth and also destroy any ark made of wood.

It's complicated cheating physics.

Re: How much power can we expect from rainfall?

#77

Post by marcus_holmes »

The point of science journalism is not to report on great science, or "speak truth to power" (the point of journalism). It is (like all other online publications) to get people to click on titles so they get shown adverts. It's not really got anything to do with how educated the readers are, it's just the business model.

I read this after reading the article about banning "persuading" advertising. In my head the two are related. If we remove "supported by advertising" as a viable business model for journalism, then it has to go back to being paid for by readers. We would get much better journalism if this happened. In fact, if we removed "supported by advertising" for everything, we'd get much better everything.

But, as TFA says, it's worrying that Nature published this crap. Nature is supported by a non-advertising business model, and although there are lots of problems with their business model, it should in theory produce good results. I wonder what happened for this article?

Re: How much power can we expect from rainfall?

#78

Post by londons_explore »

throwaway_pdp09 wrote: post #69
londons_explore wrote: post #68

Earlier quoted context omitted.

[1] probably explains the downsides best (which I had not considered). I guess considering that, the only way to make it viable is if there isn't much rainfall, or if the terrain is very flat/porus, or if you can make the collection devices very cheap (for example a kite that flies into a cloud and can collect a few tens of liters per second 1km up could generate 100 kilowatts, which is a lot less than a big wind tur…

Yeah, the effectiveness of wide area water collection is why your suggestion is 'stupid'. That's ok. Where it's possibly not stupid is in the comment you linked to "...as energy is linear with height" Sure potential energy is linear with height, but energy conversion efficiency is I think non-linear. You can I think collect more than 10x useful energy from an object that is 10x as hot. Equally I suspect you can get m…

> Equally I suspect you can get more than 10x useful energy from a column of water 10 miles high than from a column of water 1 mile high.

For a given flow rate, no.

High pressure water can be fairly efficiently converted to electrical energy, which itself can fairly efficiently be converted between low voltage+high current to high voltage+low current.

All the conversions are linear and well understood - there is no magic squared here to make this idea magic.

Re: How much power can we expect from rainfall?

#79

Post by Zenst »

hannasanarion wrote: post #9
Zenst wrote: post #4

I looked at this area a few decades ago and two approaches stood out as potential, though not stand out. 1) Roofs already collect a large surface area and funnel into a single point via roof guttering - so tapping the flow from the gutter run off would enable a viable volume of water turn a motor in the drain pipe as it descended and generate power. 2) Piezo electric generating from the roof, though was looking at a…

>Figured that tapping the drainage flow of water from a whole area combined would work better and for that need a organised drainage system all connected and yes you do get those. If I'm not mistaken, the technical term for these broad-area drainage systems is "river"

>If I'm not mistaken, the technical term for these broad-area drainage systems is "river"

In some area's/countries - yes. What I was referring to would be your towns/cities and heck in the UK, we have most accomodation plumbed for water going in and out.

Some countries/area's have what they call storm drains.

Yes they all end up at the river, ideally for the sewage - after it is treated, though again mileage may vary from country to country.

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