Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

You can have geothermal power everywhere if you drill deep enough

treehugger.com

Post reply on HN
Print view View original

301–310 of 314 posts

Re: You can have geothermal power everywhere if you drill deep enough

#301

Post by eru »

masklinn wrote: post #226
eru wrote: post #199

Earlier quoted context omitted.

Who suggested an entire country? We are talking about small-ish areas.

You have literally no idea how wide the geological destabilisation would reach.

Given the example quoted, not all that far. One article talked about Strasbourg having some minor wobbles, not the entire region. They would have surely seized on the sensationalism of reporting a wider impact.

Of course, there's no clear border. Wobbles will be biggest at the epicentre and get smaller further out.

In any case, you just do the actuarial math, and figure out how much it would cost to wobble-prove buildings in the area in question, and stick that into your cost benefit analysis. It's not like other forms of energy generation are completely without downsides either.

Re: You can have geothermal power everywhere if you drill deep enough

#302

Post by eru »

hutzlibu wrote: post #160
eru wrote: post #143

Earlier quoted context omitted.

You know that you can earthquake proof buildings? Offer to do that plus a bit of extra money on top, and you'll find plenty of rural takers. Pick the cheapest bidder.

There surely are various solutions and it is also a solution to shift side effects to areas where fewer people are affected (and more easily compensated) - but the tone of that statement above was "who cares for rural areas" at least I read it like this, because why else would rural people not care about it?

Which statement are you referring to?

I do agree with the commenter who said that we don't need to earthquake proof agricultural land itself. Especially not against minor wobbles. Fields just lie there.

(Just to avoid confusion: any buildings close to agricultural land need to be considered, of course. I am talking purely about the fields.)

Re: You can have geothermal power everywhere if you drill deep enough

#303

Post by joshspankit »

What would happen if literally everyone switched to geothermal tomorrow? Would we affect the core of the earth by extracting it’s heat at our current global usage? At double or triple our usage as the world gorges itself on this new source of clean power?

Re: You can have geothermal power everywhere if you drill deep enough

#304

Post by genewitch »

smolder wrote: post #293
genewitch wrote: post #289

Earlier quoted context omitted.

plants are 99.9999% carbon from carbon dioxide, though... what? edit: i mean of the things in a plant that contain carbon and don't, 99... whatever percent of a plant is atmospheric carbon. all the soil amendments added are to replace stuff like fungus that normally forms a relationship with nearby plants and gives nutrients that plants use to modulate energy production and transpiration (or whatever), similar to how…

Studies show higher atmospheric carbon means the crops grow faster and have lower micronutrient density than crops grown in lower co2 environments. Our crops grow faster but aren't as healthy for us.

I would like to read those, should you happen to know which ones. It seems counter-intuitive. soil amendments only including N-P-K don't seem like they'd help much with micronutrients anyhow, so ideally "functional local farming" should be considered an imperative, at least for supplementing mass-farmed foods. Like sure, canned and frozen vegetables for 6 meals a week, but one meal should have locally sourced something that hasn't been frozen or otherwise treated.

A properly managed and grown acre of land can provide a quarter ton to a ton of food in a year, but you can't use tractors or anything, it all has to be managed by hand or small machines.

Re: You can have geothermal power everywhere if you drill deep enough

#305

Post by jmacd »

FredPret wrote: post #168
jmacd wrote: post #164

Earlier quoted context omitted.

We have a ground source heat pump and one summer we were away and did not use out air conditioning that year much at all. Mid winter our return loop temperatures (the glycol being brought in to our heat pump after circulating in the ground) was at one point 3 degrees C cooler than it had been any other year. Quite a noticeable difference. For reference, our loops are 8 vertical at 250ft.

Wait, do you need eight 250ft wells?

For a closed loop system, yes. I think that would be the minimum (6000 sq ft house) at 250ft depths.

Re: You can have geothermal power everywhere if you drill deep enough

#306

Post by smolder »

genewitch wrote: post #304
smolder wrote: post #293

Earlier quoted context omitted.

Studies show higher atmospheric carbon means the crops grow faster and have lower micronutrient density than crops grown in lower co2 environments. Our crops grow faster but aren't as healthy for us.

I would like to read those, should you happen to know which ones. It seems counter-intuitive. soil amendments only including N-P-K don't seem like they'd help much with micronutrients anyhow, so ideally "functional local farming" should be considered an imperative, at least for supplementing mass-farmed foods. Like sure, canned and frozen vegetables for 6 meals a week, but one meal should have locally sourced somethi…

Not intended as snark or anything; there are a few articles about it in the HN story results you can look at: https://hn.algolia.com/?q=carbon+dioxide+crops

Re: You can have geothermal power everywhere if you drill deep enough

#307

Post by iancmceachern »

kragen wrote: post #297
iancmceachern wrote: post #250

Earlier quoted context omitted.

Thermal mass and thermal conductivity also play a role in this example. Two more reasons a wooden ladder is better in this scenario. For ladders at the same temperature, the aluminum one would conduct more thermal energy, quicker, into a user's hand then a Wooden one. Making a wooden one more usable for longer in this scenario even though the aluminum one would technically last longer. This is why wooden sauna seats…

Wood has about the same specific heat as aluminum, but a wooden ladder weighs much more, so a wooden ladder at the same temperature contains much more sensible heat to eventually conduct into the user's hand.

I looked it up. Actually wood had about twice the specific heat as aluminum. So I must revise my original comment to remove specific heat as a driving factor. This leaves only thermal conductivity. A wood ladder would have more heat to give than an aluminum one, but it still is able to give it much slower, making it ok to touch for longer.

Re: You can have geothermal power everywhere if you drill deep enough

#308

Post by kragen »

iancmceachern wrote: post #307
kragen wrote: post #297

Earlier quoted context omitted.

Wood has about the same specific heat as aluminum, but a wooden ladder weighs much more, so a wooden ladder at the same temperature contains much more sensible heat to eventually conduct into the user's hand.

I looked it up. Actually wood had about twice the specific heat as aluminum. So I must revise my original comment to remove specific heat as a driving factor. This leaves only thermal conductivity. A wood ladder would have more heat to give than an aluminum one, but it still is able to give it much slower, making it ok to touch for longer.

Agreed. I'm surprised the difference in specific heat is so large! Maybe that's fairly humid wood? Because glucose is about 220 J/mol/K https://webbook.nist.gov/cgi/cbook.cgi?ID=C492626&Mask=2#The... and 180.2 g/mol https://en.wikipedia.org/wiki/Glucose, working out to 1.2 J/g/K, and aluminum is 24.2 J/mol/K and 27.0 g/mol, giving 0.90 J/g/K.

My general rule is that everything is 1 J/g/K except water, which is 4.2. It's obviously not true, but almost always within a factor of 2, and 1 is an especially easy number to multiply and divide by.

Re: You can have geothermal power everywhere if you drill deep enough

#309

Post by dpark »

NavinF wrote: post #197
dpark wrote: post #158

Earlier quoted context omitted.

Out of curiosity, what were you digging with? Unless you were digging with a toy sand shovel or making a very large hole, that seems like a very long time. As a kid, my cousin, my sister, and myself were able to dig a hole deep enough for me to be completely inside in an hour or two using a post hole digger. (Yes, this is a very stupid idea.)

A shovel. I couldn't get past 1m because of the rocks were too difficult to shatter.

That’s fair. We were not digging through rocks.

Re: You can have geothermal power everywhere if you drill deep enough

#310

Post by jholman »

kragen wrote: post #308
iancmceachern wrote: post #307

Earlier quoted context omitted.

I looked it up. Actually wood had about twice the specific heat as aluminum. So I must revise my original comment to remove specific heat as a driving factor. This leaves only thermal conductivity. A wood ladder would have more heat to give than an aluminum one, but it still is able to give it much slower, making it ok to touch for longer.

Agreed. I'm surprised the difference in specific heat is so large! Maybe that's fairly humid wood? Because glucose is about 220 J/mol/K https://webbook.nist.gov/cgi/cbook.cgi?ID=C492626&Mask=2#The... and 180.2 g/mol https://en.wikipedia.org/wiki/Glucose , working out to 1.2 J/g/K, and aluminum is 24.2 J/mol/K and 27.0 g/mol, giving 0.90 J/g/K. My general rule is that everything is 1 J/g/K except water, which is 4.2.…

Reading your first paragraph, I was thinking "water. the answer is always water", when it comes to estimating the properties of life-stuff vs everything-else-stuff within a factor of 2. Not obviously, of course, but it's just such a powerful heuristic.

Reading your second paragraph, I see you're familiar with the principle, and added a good heuristic to my stockpile, thank you.

Post reply on HN