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Why is hydroelectricity unfashionable?

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Re: Why is hydroelectricity unfashionable?

#251

Post by idiotsecant »

c7b wrote: post #201
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. Can you elaborate? To me it always seemed like we're basically replacing a river with a lake, which doesn't seem so bad. Sure, it requires adjustment to a new equilibrium, but why is the dam lake ecosystem strictly worse than the river one? Genuinely curious, it always seemed to me that the discussion around hydropower seemed to focus solely on what is…

changing the flow characteristics of a river is a massively disruptive event, not just for the species in the water but also the animals that rely on tertiary characteristics and effects of that river. It changes the erosion patterns and sediment carrying capacity of the stream, it changes the seasonal flows that ecosystems have come to rely on, it changes nutrient transport, changes water temperature, changes oxygen content, and a million other things that make the stream less compatible with certain species and more compatible for others. Best case this results in loss of biodiversity, worst case it results in spread of invasive species that have even further impacts on an even wider swatch of the ecosystem. It doesn't make the ecosystem go away, it just changes it to a less settled one - generally when that happens the complexity of the ecosystem goes down until natural selection can catch back up and everything adapts to fill the same niches again, which is not a fast process.

It's hugely disruptive to ecosystems.

Re: Why is hydroelectricity unfashionable?

#252

Post by sidewndr46 »

pfdietz wrote: post #246
sidewndr46 wrote: post #166

Earlier quoted context omitted.

Wouldn't this mean the downstream would have no water flowing through it?

Pumped hydro can be built entirely off rivers. There's a plan to put a reservoir for one on top of a mesa in the desert in Arizona, for example.

What does the location of the reservoir matter? If you're taking a river and pumping it up on top of somewhere (a mesa in your example) aren't you going to cause the river to basically run dry everywhere downstream of where your pump is?

Re: Why is hydroelectricity unfashionable?

#253

Post by pfdietz »

sidewndr46 wrote: post #252
pfdietz wrote: post #246

Earlier quoted context omitted.

Pumped hydro can be built entirely off rivers. There's a plan to put a reservoir for one on top of a mesa in the desert in Arizona, for example.

What does the location of the reservoir matter? If you're taking a river and pumping it up on top of somewhere (a mesa in your example) aren't you going to cause the river to basically run dry everywhere downstream of where your pump is?

There's no river at the bottom, either. I thought the "desert" part would make that clear, but I guess it had to be said.

Water in this system is part of the capital cost (charging it up when you start), then a minor maintenance cost (replacing evaporation). Otherwise, unlike primary hydro, there is no large constant flow out of the system, and no need to be on a river.

The water lost to evaporation is at least an order of magnitude less than water evaporated from a nuclear plant of the same levelized power.

Re: Why is hydroelectricity unfashionable?

#254

Post by brianwawok »

jjk166 wrote: post #125
whatshisface wrote: post #109

Earlier quoted context omitted.

It is a good thing then that nature has already done the excavation for us by providing high and low spots.

Yep, now we just need to excavate the reservoirs on those high and low spots, a mere 100% of the work required.

This is nonsense. We have lakes already. We don’t dig two giant holes in rock. Look at real work pumped storage costs.

Re: Why is hydroelectricity unfashionable?

#255

Post by mjevans »

philipkglass wrote: post #118
ClumsyPilot wrote: post #43

Earlier quoted context omitted.

> We need storage and pumped storage is the only practical way to get there with current supply chains and technology. This really cannot be enphasised enough - this is the only game in town. The solutions are needed yesterday, and must be built on a massive scale - there is no time for a 20 year R&D to production cycle of a miracle technology. Only hydro does not require any new minerals and mining. The only other c…

The only other contender that is even worth mentioning is compressed gas, but it seems to have neither the capacity nor the efficiency of a large hydro deployment. The largest pumped storage station in the US has a storage capacity of 24,000 MWh: https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... There's an underground hydrogen storage project underway in Delta, Utah with a capacity of 300,000 MWh: https…

I thought it was missing from the list...

https://en.wikipedia.org/wiki/Grand_Coulee_Dam#Irrigation

However it seems that the pumped storage I recall hearing about as a kid has an extremely low storage capacity and is more focused on irrigation.

Re: Why is hydroelectricity unfashionable?

#256

Post by rdtwo »

ClumsyPilot wrote: post #221
philipkglass wrote: post #118

Earlier quoted context omitted.

The only other contender that is even worth mentioning is compressed gas, but it seems to have neither the capacity nor the efficiency of a large hydro deployment. The largest pumped storage station in the US has a storage capacity of 24,000 MWh: https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... There's an underground hydrogen storage project underway in Delta, Utah with a capacity of 300,000 MWh: https…

You are confusing energy storage and fuel storage. I am talking about CAES, it uses electricity to compress air and feed that into a container, like a metal cylinder or caverns lined with impermeable material. When you need electricity, you release the air through a generator and produce electricity. Hydroelectric, compressed air and batteries have round trip efficiency of ~80%. https://www.sciencedirect.com/topics/e…

Russians did that at some point in the 70s 80s. They pumped compressed air into some salt mines and that worked well until one of the mines sprung a leak and blew the mountain up

Re: Why is hydroelectricity unfashionable?

#257

Post by sidewndr46 »

pfdietz wrote: post #253
sidewndr46 wrote: post #252

Earlier quoted context omitted.

What does the location of the reservoir matter? If you're taking a river and pumping it up on top of somewhere (a mesa in your example) aren't you going to cause the river to basically run dry everywhere downstream of where your pump is?

There's no river at the bottom, either. I thought the "desert" part would make that clear, but I guess it had to be said. Water in this system is part of the capital cost (charging it up when you start), then a minor maintenance cost (replacing evaporation). Otherwise, unlike primary hydro, there is no large constant flow out of the system, and no need to be on a river. The water lost to evaporation is at least an or…

Wouldn't you need two reservoirs in that case? Otherwise where is the water being drained down to take advantage of the potential energy?

Re: Why is hydroelectricity unfashionable?

#258

Post by grogenaut »

didgetmaster wrote: post #147
tialaramex wrote: post #124

Earlier quoted context omitted.

> I understand that hydroelectricity is used to supply the basic power need, say 80% and a water reservoir with turbines to cover power peak needs This seems like you either didn't understand what pumped storage is, or you've confused several related technologies. A typical pumped storage scheme goes like this: We find a mountain with a high lake and a low lake. We dam the high lake so that its natural outflow (perha…

Do you know the efficiency of using pumped storage? In other words, for every MW of electricity used to pump the water up the hill, how much do you get back in power generation when the water flows back down through a turbine? You will lose a bit of water to evaporation during this process, but it should be fairly negligible. Also all reservoirs lose some water by leakage into the ground. How does the efficiency comp…

Lets take a pumped hydro I know of, https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_.... It's 5,370,000 m^3 of water, 3600 MW·h for 8 hours to empty, 28,800 MW total. Cubic meter of water weighs 1,000 kg aka a metric ton. So 5,370,000 Metric tons of water.

Looking at https://energetechsolar.com/1mwh-500v-800v-battery-energy-st..., they're around .88 LB / AH, so 880,000 LB/MWh. 399,161 KG / MWh. 11,179,036,800, or 11,179,036 Metric tons of batteries. I don't know what the breakdown is but global lithium production was 100,000 metric tons in 2021, which is off by 2 oom.

My math may be wrong, and you do have losses of water from evaporation, but with pumped you can go up and down. But that's 11 million metric tons of lithium and other metals. Water falls from the sky (in most places still). Lithium has to be refined. You can recharge the battery, you can reload the water or pump it the other way. Tomsauk is mostly concrete and water (by volume). You do need almost a mountain for that head, or a mine. Concrete breaks down over time and can be maintained,. Batteries wear out as well but can be rebuilt. Water seems the easiest of the things to replace currently. The only things I can think of that are easier are provably gasses and maybe salt or rock.

This is all napkin math, and I may have missed a decimal some places. But they seem within the same order of magnitude for efficiency. But is it even possible to build batteries that big?

Of course when they got greedy with Tomsauk they ruind a great natural area. I'd love to be corrected on my math and assumptions.

Re: Why is hydroelectricity unfashionable?

#259

Post by seabrookmx »

chewbacha wrote: post #155

I was hoping that the author would address the environmental concerns. But instead, they are mentioned and then dismissed without argument. The enumerations are many that are mentioned: They are blamed for displacing populations, disrupting the flow of sediments and the migration of fish, destroying natural habitat and biodiversity, degrading water quality, and for the decay of submerged vegetation and the consequent…

And wind turbines decimate bird populations.

I wouldn't be surprised if solar panels had a negative impact on insect species.

Where is the magical green line?

I think most people equate "green" to anything not involving petroleum.

Re: Why is hydroelectricity unfashionable?

#260

Post by credit_guy »

ClumsyPilot wrote: post #43
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…

> We need storage and pumped storage is the only practical way to get there with current supply chains and technology. This really cannot be enphasised enough - this is the only game in town. The solutions are needed yesterday, and must be built on a massive scale - there is no time for a 20 year R&D to production cycle of a miracle technology. Only hydro does not require any new minerals and mining. The only other c…

> this is the only game in town.

There is another game in town. Emphasis on "is", as in present tense, not future. Natural gas power plants. They emit much, much less CO2 than coal. If we use them to only generate electricity when solar and wind are not enough, we end up with much lower emissions than what the trees remove from the atmosphere. We also end up needing to overbuild solar and wind by only about 30%, not by a factor of 3 or 4. The capital cost of maintaining the current, existing, natural gas power plants is basically zero. The capital cost of building new pumped storage is huge.

Here, let me do it for you. Lifting 1 kg to a height of 1 m requires about 10 Joules (more precisely 9.8, as every high school student hopefully knows). One billion kg, or one million tons is 10 giga-joule, or giga-watt-seconds. Increase to 360 million tons, and you get one GigaWatt-hour. One ton is one cubic meter of water, one million is a square of 1km2 area and 1m height, and 360 megatons is a square of horizontal width and length of 6 km and a height of 10 meters. A fairly big lake. Building an artificial one would qualify as a mega-project. It would cost multiple billions of dollars. It would be able to generate one gigawatt of power for one hour. Of course you'd raise it to a certain height, let's say 100 meters, and that would generate the 1GW of power for 4 days. If you have 100% efficiency. Which you don't have, because you lose energy both when you pump up, and when you let the water come down. Assuming an optimistic 25% overall round-trip efficiency, you get 1GW power for one day. If you want for one month, well, you multiply this by 30.

Or you can just keep around a 1GW natural gas power plant, and use it when you need it.

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