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

Why is hydroelectricity unfashionable?

spectrum.ieee.org

Post reply on HN
Print view View original

221–230 of 397 posts

Re: Why is hydroelectricity unfashionable?

#221

Post by ClumsyPilot »

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…

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/engineering/compressed-...

The facility you linked produces and stores chemical fuel, and can't even convert it back into electricity. It is really easy to store insane quantity of fuel, just like we can store loads of oil.

The kicker is that production of Hydrogen and other e-fuelds is less than 50% efficient, and converting them back to electricity is another 50% loss. Compression for storage and transportation mean further losses. So the overall round-trip efficiency is expected to be about 25% or lower.

It is probably possible to build an economy based on e-fuels, and that's what many oil companies are pushing for. They are probably the only viable way to achieve seasonal storage. It's a different set of tradeoffs.

Re: Why is hydroelectricity unfashionable?

#222

Post by roamerz »

azylman wrote: post #168
roamerz wrote: post #122

Earlier quoted context omitted.

That ship has already sailed as most power producing dams have been around for long time. Removing them would destroy the (now natural) ecosystem they have created. Plus dams have way more benefits to us than the extremely clean energy they produce - not just store.

This is not the case, removing dams still can come with huge benefits to the ecosystems those dams disrupted: https://www.mercurynews.com/2019/05/08/four-years-after-cali...

Read the article. Sounds like in that instance it was a good choice to remove the dam and had a good outcome. Well based on the information presented anyhow. Also I’m not sure if the main justification for removal pencils out for me. Yes some fish - 123 so far - were able to reproduce further upstream by 7 miles. What would have happened if the dam was still in place? Breed just below the dam? Do the fish really care where they do the deed or lay their eggs? Can’t believe that would be very true. Heck when I was their age I was pretty happy to do the deed and wasn’t too too awful concerned where it was at either. :D

Re: Why is hydroelectricity unfashionable?

#223

Post by [deleted] »

exabrial wrote: post #104
falcolas wrote: post #26

Earlier quoted context omitted.

Downstream actually sees benefits from a dam, since the output of the river remains unnaturally constant even during periods of drought. The immediate upstream from a dam, however, is another story entirely.

Floods are as natural as rain, wildfires, and erosion. Entire species depend on these. A good example is how we almost managed to destroy all of the sandbars on the Colorado river because we were "controlling flooding", but it took quite a while for us to realize these are only created during surge events.

[deleted]

Re: Why is hydroelectricity unfashionable?

#224

Post by mindslight »

Retric wrote: post #171
azylman wrote: post #167

Earlier quoted context omitted.

If this still builds a dam, doesn't this have the same environmental concerns as any hydro project? Or is there something that makes this less of a concern?

Ideally you don’t build a dam. Niagara Falls sits between Lake Erie into Lake Ontario. Which is the perfect location to use pumped hydro because all you need to build is a pipe between them and put a turbine inside the pipe. If you have excess energy pump water up from Lake Ontario to Lake Erie, and when you need power run that in reverse to generate electricity. Move enough water and the water level on each lake wil…

The scenario you've described still begs the question though. It seems the only difference between traditional hydroelectricity and pumped storage is how much you disrupt the natural flow from Lake Erie to Lake Ontario. The hard limit is when the Niagara Falls run dry. Anything more than that is basically spending electricity to create a treadmill for fish, which may be the environmentally responsible thing but we should be clear about that. And since fish probably cannot jump up Niagara Falls, it's probably more like spending electricity to run a really large water display for tourists and the occasional person who wants to go over in a barrel. But maybe that electricity use doesn't matter if we're getting more than we need from solar during sunny days, and just need predicable storage for nights and cloudy days.

I would think the stronger argument for pumped storage would be in a place where the high level of water did not naturally exist, and so the only way it gets up there is by pumping. But perhaps this still destroys too much of an ecosystem even if it's not a river ecosystem.

Re: Why is hydroelectricity unfashionable?

#225

Post by Manuel_D »

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…

Such hydrogen storage facilities already exist, actually. But the hydrogen the store is produced via steam reformation which emits carbon. The big issue with hydrogen storage cheaply producing hydrogen without producing CO2.

Re: Why is hydroelectricity unfashionable?

#226

Post by 01100011 »

exabrial wrote: post #204
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…

I think the main reason is that not everybody has the geography conducive for pumped Hydro. Here in Kansas we have a ton of wind energy production and we’re lucky enough to have a nuclear reactor as well. It’d really be nice to store that, but we have no mountains. We have a rolling plain in the middle of the state but even the highest/lowest delta is like 200-300 ft (I made that number up).

Can you create an underground reservoir, say from an expired oil field, that is of sufficient capacity to create a pumped hydro system in concert with a ground-level reservoir?

Re: Why is hydroelectricity unfashionable?

#227

Post by kenhwang »

bluescrn wrote: post #218
bryanlarsen wrote: post #57

Earlier quoted context omitted.

We certainly can use solar, wind & batteries to eliminate fossil fuels from our electricity system. Estimates are that we'd need about 300TWh of batteries, which is on the edge of feasible. Pumped storage would be a lot cheaper, though.

And what percentage of the immense quantity of batteries would need replacing each year?

They're currently rated for 20 years of usable life, so you'd replace 5% of them a year. They're supposedly 95%+ recyclable, it's just not currently economically viable to do so since only cobalt and nickel are cheaper to reuse than to newly mine.

Re: Why is hydroelectricity unfashionable?

#228

Post by 01100011 »

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…

Is there a reason why you wouldn't combine pumped hydro with a diverted fraction of a natural river? You get the ability to store electricity along with some pure generation capacity while still allowing the river to mostly flow unimpeded. You're already building the generation capacity, and this allows you to generate some electricity 24/7 if the need arises. It seems feasible to divert a fraction of a river's flow, provided you work with natural, seasonally fluctuating flow rates, and not severely disturb wildlife. i.e. distribute the diversion plumbing over a mile of the river course.

Re: Why is hydroelectricity unfashionable?

#229

Post by philipkglass »

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…

The facility you linked produces and stores chemical fuel, and can't even convert it back into electricity.

The project includes using Mitsubishi M501JAC combined-cycle gas turbines to turn the hydrogen back into electricity:

https://www.powermag.com/aces-deltas-giant-utah-salt-cavern-...

https://power.mhi.com/products/gasturbines/lineup/m501j

This turbine has a rated combined-cycle efficiency of 64%.

Production of hydrogen is more than 70% efficient in the best current commercial electrolyzers:

https://www.nrel.gov/docs/fy04osti/36705.pdf

Round-trip efficiency is much lower than 80%, but not as low as you have written here.

Post reply on HN