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Why is hydroelectricity unfashionable?

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Re: Why is hydroelectricity unfashionable?

#391

Post by pencilguin »

credit_guy wrote: post #389
Schroedingersat wrote: post #386

Earlier quoted context omitted.

> Right now, all the natural gas power plants in the US produce about 12% of the total (gross) emissions. If we use these plants only when there's not enough electricity from solar, wind, hydro and nuclear, we'll reduce their emissions by a factor of 10. Concluding that we'd only need 2% of the current emissions from this is a bit misleading. The overwhelming majority of emissions currently don't come from electricit…

Let's say you want to reduce emissions by the equivalent of a 1GW natural gas power station. Option 1: Build enough solar and wind to replace the electricity generated by the power station; in fact overbuild by let's say 30%. You can afford that because solar and wind are cheap. And then build pumped storage to be able to add an extra 300 MW for a few weeks, when you need that. Decommission the natural gas power stat…

And, costs for everything are shifting throughout, with new technologies appearing randomly. The right answer today might be wrong tomorrow.

Re: Why is hydroelectricity unfashionable?

#393

Post by Schroedingersat »

credit_guy wrote: post #389
Schroedingersat wrote: post #386

Earlier quoted context omitted.

> Right now, all the natural gas power plants in the US produce about 12% of the total (gross) emissions. If we use these plants only when there's not enough electricity from solar, wind, hydro and nuclear, we'll reduce their emissions by a factor of 10. Concluding that we'd only need 2% of the current emissions from this is a bit misleading. The overwhelming majority of emissions currently don't come from electricit…

Let's say you want to reduce emissions by the equivalent of a 1GW natural gas power station. Option 1: Build enough solar and wind to replace the electricity generated by the power station; in fact overbuild by let's say 30%. You can afford that because solar and wind are cheap. And then build pumped storage to be able to add an extra 300 MW for a few weeks, when you need that. Decommission the natural gas power stat…

My point is that pumped hydro is hardly being built, but battery storage is growing very fast even at much higher costs (due to the other advantages). Step zero is, as always, build wind and solar but once you reach step one (and some places have) pumped hydro is hardly 'the only game in town', and it's not even obvious if it will remain a good option even if you have an excellent site.

Re: Why is hydroelectricity unfashionable?

#394

Post by Handytinge »

jeffparsons wrote: post #276
idiotsecant wrote: post #37

Obviously hydroelectricity is massively damaging to ecosystems. My day job includes designing hydroelectric control systems and even I can admit that. That's a big part of the reason that hydro is a non-starter in much of the western world, which is probably a reasonably good thing (although there are certainly some exceptions where hydro development seems like a no-brainer to me but I digress) What's not so clear to…

Here in Australia we apparently have a virtually limitless supply of sites that are very well suited to "off-river pumped hydro", and yet there doesn't seem to be any action on this front. I find this extra surprising because we also desperately need better fresh water management for other reasons, not least of which being our country's tendency to alternate between drought and flood. There must be some reason we're…

What are you talking about?

Tasmania has had significant hydro since 1895, is currently 80% hydro powered and is 100% renewable (and aiming for 200%, to increase green supply to the mainland).

Re: Why is hydroelectricity unfashionable?

#395

Post by idiotsecant »

b112 wrote: post #194
idiotsecant wrote: post #37

Obviously hydroelectricity is massively damaging to ecosystems. My day job includes designing hydroelectric control systems and even I can admit that. That's a big part of the reason that hydro is a non-starter in much of the western world, which is probably a reasonably good thing (although there are certainly some exceptions where hydro development seems like a no-brainer to me but I digress) What's not so clear to…

Obviously hydroelectricity is massively damaging to ecosystems False. A river is not a static thing. Nor a lake. Rivers, lakes, swamps, bodies of water change over thousands, and even hundreds of years. A lake today, is a river tomorrow, and vice versa. Terrain erodes, shifts, rivers dry up, or appear from nothing. Go back in time, in 10k increments, and see how a local area changes. To claim that a hydroelectric dam…

You're right - building a dam and waiting for a thousand years will result in a new stable ecosystem with biodiversity comparable to the original. The problem is that natural systems need 'settling time' to adapt to changing conditions. The immediate impact in dams is a dramatic drop in biodiversity, that's not even a controversial claim. It's great that the ecosystem will rebound after I'm dead but I don't think that's what most people are concerned about. Deforestation and desertification of formerly healthy riparian ecosystems isn't a trivial concern. Not all 'changes' in nature are equally beneficial to humans.

Re: Why is hydroelectricity unfashionable?

#396

Post by pencilguin »

Schroedingersat wrote: post #393
credit_guy wrote: post #389

Earlier quoted context omitted.

Let's say you want to reduce emissions by the equivalent of a 1GW natural gas power station. Option 1: Build enough solar and wind to replace the electricity generated by the power station; in fact overbuild by let's say 30%. You can afford that because solar and wind are cheap. And then build pumped storage to be able to add an extra 300 MW for a few weeks, when you need that. Decommission the natural gas power stat…

My point is that pumped hydro is hardly being built, but battery storage is growing very fast even at much higher costs (due to the other advantages). Step zero is, as always, build wind and solar but once you reach step one (and some places have) pumped hydro is hardly 'the only game in town', and it's not even obvious if it will remain a good option even if you have an excellent site.

Battery storage being built today is, correctly, almost all for shifting afternoon collection to evening usage, where batteries are best suited by their unlimited charge and discharge wattage, and their high cost per MWh stored matters least.

For storage beyond 4 hours, other considerations become important, particularly cost per MWh stored. You still need to extract plenty of wattage, but charge rate matters less. So, you need big or many turbines, but pumps can be slower. And, of course, retrofitting the many existing reservoirs is cheapest, so you do that before building anew.

Fuel storage similarly takes advantage of existing combined-cycle turbines, which are being adapted to burn a gradually increasing fraction of hydrogen. It remains to be seen whether they can be made to burn ammonia directly, or if the ammonia must first release its hydrogen. Stored fuel has the great advantage that it can be shipped, bought, and sold.

Re: Why is hydroelectricity unfashionable?

#397

Post by zizee »

BatteryMountain wrote: post #339
zizee wrote: post #161

Earlier quoted context omitted.

Pumped hydro needs to be truely massive scale, both in the amount of water (read: lots of depth AND surface area), and the height differential between the two reservoirs. To make it cost feasible we really need very favourable natural geography. Building such structures ourselves would be astronomically expensive.

Check the one near Cape Town. It can run for up to 12 hours with two "small" dams and the altitudes for the dams are ~100m & ~350m respectively, connected by water tunnels & 4 turbines. It is located in the mountains, right next to the coast (which I think minimizes negatives further). The the size and rainfall season matters for how long they can run. Cape Town has a winter-rain season that runs from roughly May to…

This one? Looks interesting.

https://en.m.wikipedia.org/wiki/Steenbras_Power_Station

The capacity of the smaller of the two dams is 3,560 megalitres. I think a 1km X 350m X 10m deep is this capacity. So "small" is fairly subjective term, but you are right that it is not gargantuan. It is still not going to be easy to place such a setup just anywhere, but I'm willing to admit my statements may have been a little too much.

I would be interested in how much it cost to build and run to obtain the 180mwh capacity. A similarly size gridscale battery would cost in the vicinity of 40-60 million USD (using the $140 per kWh cost, numbers are is hard to find for the supporting equipment and installation costs).

There is probably an inflection point where pumped storage becomes more economical than batteries. With land and labour costs so different from lace to place what makes sense in certain areas, is probably not economical in others.

https://www.morningbrew.com/series/battery-tech-for-evs-and-...

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