How much power can we expect from rainfall? • Hacker News Board

Re: How much power can we expect from rainfall?

#101

Post by traverseda » Mon, Apr 27, 2020, 6:43 PM UTC

bathtub365 wrote: post #93

gherkinnn wrote: post #82

Earlier quoted context omitted.

That body of water also needs to be placed high enough for it to release a waterfall. I can’t think of something. Some large geological structures, perhaps? I dunno. Maybe Elon Musk has a wacky idea to inverse this problem and build tunnels below lakes to make this work.

Coquitlam Lake actually has a tunnel leading to Buntzen Lake for the purposes of supplying it with water for power generation. Pipes then carry the water down to a generating station on the ocean shore. https://curiocity.com/vancouver/wp-content/uploads/2019/08/p...

Yes, the joke is that we are describing a hydroelectric dam.

Re: How much power can we expect from rainfall?

#102

Post by marcus_holmes » Mon, Apr 27, 2020, 8:26 PM UTC

zdragnar wrote: post #98

marcus_holmes wrote: post #97

Earlier quoted context omitted.

Interesting. What is the point of journalism then?

Obviously, that depends on where in the world you are. Assuming a press that is relatively free from government and adversarial editorial oversight, journalism can likely be summed up as "obtaining newsworthy information and publishing it to the public". According to Wikipedia, at least, there are at least 242 ethics standards for journalism worldwide, with something of a general consensus on truthfulness, accuracy,…

Yeah. I guess most of that "information" aspect is now being done by t'intertubes.

Maybe I should rephrase my original to be "the important point of journalism is speaking truth to power".

Seeing what a farce the UK media is making of Assange's trial (sorry, extradition hearing), it seems we're nowhere near that at the moment.

Re: How much power can we expect from rainfall?

#103

Post by ctdonath » Mon, Apr 27, 2020, 9:12 PM UTC

smaddox wrote: post #88

ctdonath wrote: post #87

One sentence that should have been elaborate on a bit more to mirror/complete the article’s approach: “For a sense of scale, a solar panel gets around ten thousand times this, or 100 Watts per square meter.” Solar power has the same problem of terminal optimism as the proposed raindrop energy harvesting: in short, the source 1300W/m^2, all factors considered, becomes a real world 13W/m^2. Better than raindrops fallin…

Do you have a source for 13W/m^2? That looks about an order of magnitude low to me.

Math. Once you account for night, impingement angle, weather, atmospheric absorption, panel efficiency, dirt, seasons, storage efficiency, etc it averages out around 13W/m^2 long term.

Experience. I run my “office” all summer on solar. 1m^2 panel gives 70W max; usable light about 8 hours, average over a day is 23W. Halve that for winter, overcast, etc.

Re: How much power can we expect from rainfall?

#104

Post by pintxo » Tue, Apr 28, 2020, 9:46 AM UTC

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?

Cannons: https://youtu.be/l9qA8c-E_oA

Re: How much power can we expect from rainfall?

#105

Post by pintxo » Tue, Apr 28, 2020, 9:50 AM UTC

csours wrote: post #14

SlowRobotAhead wrote: post #12

Earlier quoted context omitted.

I think you’re on to something there. What if we made on very large, and collected lots of water at a central point and could control how much of it we use for electricity? It’s a damn good idea.

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!

You mean like a 250m high wave?

https://en.wikipedia.org/wiki/Vajont_Dam#Landslide_and_wave

Re: How much power can we expect from rainfall?

#106

Post by pintxo » Tue, Apr 28, 2020, 9:58 AM UTC

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…

Funny no one has cited Randals What-If yet: https://what-if.xkcd.com/23/ (third question on the list)

Back of the envelop calculations would have break even after about 100 years...

Re: How much power can we expect from rainfall?

#107

Post by jshevek » Tue, Apr 28, 2020, 5:48 PM UTC

bathtub365 wrote: post #93

gherkinnn wrote: post #82

Earlier quoted context omitted.

That body of water also needs to be placed high enough for it to release a waterfall. I can’t think of something. Some large geological structures, perhaps? I dunno. Maybe Elon Musk has a wacky idea to inverse this problem and build tunnels below lakes to make this work.

Coquitlam Lake actually has a tunnel leading to Buntzen Lake for the purposes of supplying it with water for power generation. Pipes then carry the water down to a generating station on the ocean shore. https://curiocity.com/vancouver/wp-content/uploads/2019/08/p...

The culture of hackernews is being poisoned by the culture of reddit during this pandemic.

Re: How much power can we expect from rainfall?

#108

Post by smaddox » Wed, Apr 29, 2020, 3:36 AM UTC

ctdonath wrote: post #103

smaddox wrote: post #88

Earlier quoted context omitted.

Do you have a source for 13W/m^2? That looks about an order of magnitude low to me.

Math. Once you account for night, impingement angle, weather, atmospheric absorption, panel efficiency, dirt, seasons, storage efficiency, etc it averages out around 13W/m^2 long term. Experience. I run my “office” all summer on solar. 1m^2 panel gives 70W max; usable light about 8 hours, average over a day is 23W. Halve that for winter, overcast, etc.

Gotcha. That still seems a bit low for where I live, assuming 18% efficient panels. Roughly 5kW.hr/m^2 averaged over the year, so 5000/24*0.18 = 37.5 W/m^2.

And of course solar thermal in the desert can do quite a bit better than that.

Re: How much power can we expect from rainfall?

#109

Post by bathtub365 » Wed, Apr 29, 2020, 3:18 PM UTC

jshevek wrote: post #107

bathtub365 wrote: post #93

Earlier quoted context omitted.

Coquitlam Lake actually has a tunnel leading to Buntzen Lake for the purposes of supplying it with water for power generation. Pipes then carry the water down to a generating station on the ocean shore. https://curiocity.com/vancouver/wp-content/uploads/2019/08/p...

The culture of hackernews is being poisoned by the culture of reddit during this pandemic.

What is the culture of reddit? I don't read or post there.

Re: How much power can we expect from rainfall?

#110

Post by jshevek » Wed, Apr 29, 2020, 8:58 PM UTC

bathtub365 wrote: post #109

jshevek wrote: post #107

Earlier quoted context omitted.

The culture of hackernews is being poisoned by the culture of reddit during this pandemic.

What is the culture of reddit? I don't read or post there.

There are many aspects of the culture of reddit which is poisoning the culture of hackernews during this pandemic, to save time I'll just address the portion of reddit culture that is evidenced here: the practice of pretending to invent something that already exists and naming it in a manner somewhat analogous to its existing name.

The is a special case of the culture of repetitive, unimaginative, formulaic humor threads in which a series of people pretend to engage in a conversation in earnest, but the entire thread is satire, or meta, or fake invention, etc.

Edit: It seems to me that there is a correlation between the users who participate in these kinds of threads, and the users who damage the culture of HN in other ways. I'm not speaking of the specific users in this particular humor thread, but what I've seen in the past of humor threads in general. Clicking on their profile and viewing past comments, I've found that humor-thread participants often also engage in ideological battle, rely heavily on emotionally manipulative rhetoric, make low quality fallacious arguments, etc.