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Why is hydroelectricity unfashionable?

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Re: Why is hydroelectricity unfashionable?

#371

Post by pencilguin »

zizee wrote: post #350
pencilguin wrote: post #303

Earlier quoted context omitted.

Pumped hydro does not, in fact , need "lots of depth". 10m is typical, for which cheap earthen dikes suffice. It does not, in fact , need "very favourable natural geography". It needs an elevation difference, something found almost everywhere, Holland and Kansas excepted. Kansas has deep underground cavities, which also suffice. Building dikes is cheap and low tech. Dikes predate written language.

On the depth thing, I really only meant to mean you need lots and lots of water. You could have a shallow basis, and take over a huge area of land, or or smaller amount of land if you have deeper water. Deeper also allows for less evaporation, less land area. Perhaps your and my definitions of favourable geography are different. You need a water source, due to evaporation, you need a big resovoir at elevation, and an…

You don't need a "huge area of land", under any circumstance. Even a football pitch is big enough for useful storage. Permeability is a thing that is controllable. Since there are so very many hills, only the most favorable sites need be considered.

The main reason it is not being rolled out much is that it is not time yet to roll it out. You need enough spare renewable generating capacity to charge it from, first, which we are very far from, most places. In the meantime the right place to spend is on generating capacity. Later, we will know better which storage methods are best.

Re: Why is hydroelectricity unfashionable?

#372

Post by pencilguin »

Gibbon1 wrote: post #320
fomine3 wrote: post #316

Earlier quoted context omitted.

For nuclear era, it was easier to pay cost for storage because same operator built both nuclear plant and pumped storage. Even if operator isn't same, there are only few nuclear operator in the grid so easier to talk. For PV (or say electricity deregulation) era, it will be a bit difficult since PVs are deployed by small operators or individuals. Great market mechanism or govt regulation is needed.

California quietly added 3GW of batteries in the last three years to shift mid day solar to the evening. I think part of the quietly bit is locating them at mothballed natural gas peaking plants. Advantage the power infrastructure is there and no use change permits needed.

Before that, they attached pumps and ponds at the bottom of penstocks leading to reservoirs in the Sierra Nevada mountains that were built decades ago.

Re: Why is hydroelectricity unfashionable?

#373

Post by pencilguin »

Manuel_D wrote: post #369
pencilguin wrote: post #279

Earlier quoted context omitted.

There is in fact no such issue because literally no one is even considering producing hydrogen for energy storage in that way.

Then how is hydrogen going to be stored? Electrolysis remains either inefficient or expensive.

Storage method has exactly nothing to do with production method.

Electrolysis efficiency and expense are entirely sufficient to requirements for the hydrogen storage projects are, in fact, proceeding.

Re: Why is hydroelectricity unfashionable?

#374

Post by laverya »

pencilguin wrote: post #370
laverya wrote: post #362

Earlier quoted context omitted.

No matter where you put the few cubic kilometers of water that pumped hydro requires, you need to put it somewhere . The ecosystem of that place will then be displaced or destroyed.

It does not need more than the tiniest fraction of a cubic km of water. A reservoir can increase scarce habitat for migratory birds, which is commonly much more valuable than your typical bald hilltop.

> It does not need more than the tiniest fraction of a cubic km of water.

One cubic km is one billion tons. Each ton is ~10kJ per meter lifted, and let's assume you can separate your reservoirs by 100m vertically.

That would give a total system capacity of 1e9 tons x 1e5 J/(ton x meter) x 1e3 meters, or 1e17 Joules.

A kilowatt hour is 3.6e6 Joules, so this gives us ~3e10 KWh. If we're imperfect in reclaiming that energy, we'll actually end up with 1-2e10 KWh.

US annual electricity consumption was ~4e12 KWh/year in 2018 (or ~1e10 KWh/day), so a 1km^3 * 100m installation is probably larger than required to provide a backup for replacing our entire electrical generation infrastructure with intermittent sources 99.9% of the time. Not by a huge amount though! Less than an order of magnitude, IMO.

> A reservoir can increase scarce habitat for migratory birds, which is commonly much more valuable than your typical bald hilltop.

How much is the level going to fluctuate on a daily basis, though? Does it really form useful habitat?

Re: Why is hydroelectricity unfashionable?

#375

Post by pencilguin »

kkfx wrote: post #331
pencilguin wrote: post #314

Earlier quoted context omitted.

Hydro power turbines and nukes' steam turbines are similar only in the name, and that just because both turn.

They are both build with the same industrial process, demand similar alloys, similar CFD calculus etc. Witch means: if you can build one for hydro you can build one for nuclear. If you can't for nuclear than you can't equally for hydro and vice versa. That's why they are a big business for very few developed countries supply chain. Do NEVER forget that anything at a certain scale is a matter of know how, supply chain…

They do not, in fact, demand similar alloys. A hydro power turbine operates with liquid water, a steam turbine with superheated, corrosive steam.

A Pelton wheel is fundamentally different in every detail from a steam turbine. Useful Pelton wheels have been made in village smitheries. They are readily mass-produced, and last many decades without need for service.

Re: Why is hydroelectricity unfashionable?

#376

Post by pencilguin »

laverya wrote: post #374
pencilguin wrote: post #370

Earlier quoted context omitted.

It does not need more than the tiniest fraction of a cubic km of water. A reservoir can increase scarce habitat for migratory birds, which is commonly much more valuable than your typical bald hilltop.

> It does not need more than the tiniest fraction of a cubic km of water. One cubic km is one billion tons. Each ton is ~10kJ per meter lifted, and let's assume you can separate your reservoirs by 100m vertically. That would give a total system capacity of 1e9 tons x 1e5 J/(ton x meter) x 1e3 meters, or 1e17 Joules. A kilowatt hour is 3.6e6 Joules, so this gives us ~3e10 KWh. If we're imperfect in reclaiming that ene…

There are plenty of hills much more than 100m high. People will favor using the best places for it.

Efficiency of pumped hydro is always better than 70%, round-trip, and commonly better than 85%.

There is no reason to put all your storage in one place, and great reasons not to. A site moving 0.0001 km³ is useful for utility-scale storage. Of course, pumped hydro will be only one storage method among many.

Birds mostly use the top of the water. Probably, the lower pond is easiest to tailor for multiple use, but "floatovoltaics" are probably better in the upper one.

Re: Why is hydroelectricity unfashionable?

#377

Post by Retric »

mindslight wrote: post #365
Retric wrote: post #242

Earlier quoted context omitted.

We let stuff migrate upriver years ago when they added a lock system back in 1829. At this point any environmental harm from connecting these lakes has already happened generations ago well before we where born. https://en.wikipedia.org/wiki/Welland_Canal Anyway, the amount of water flowing over Niagara Falls is currently regulated hourly by treaty with excess flows above that level used to generate hydroelectricity.…

Connecting two bodies of water for the occasional organism that wants to pass through is a distinct thing from disconnecting two bodies of water for say large numbers of fish that would otherwise swim up a river. The latter is a usual criticism of hydro power, which seems like it doesn't apply to Niagara because it's such a big waterfall. I wasn't aware of the treaty, that makes sense. The link about turning off the…

I assume they sent the water over the Canadian side simply due to the treaty. That said, they have excess capacity to handle blocking 1/2 the flow over Niagara Falls every night, but even doing nothing was still a non issue.

If you assume they blocked 1/2 the flow (1,400 m3/s) and didn’t use it for anything. That would still take 21 days to raise water level of Lake Erie by 1cm.

Re: Why is hydroelectricity unfashionable?

#380

Post by liketochill »

kenhwang wrote: post #227
bluescrn wrote: post #218

Earlier quoted context omitted.

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.

Any source for the 20 years?

A project I had a colleague working on where the batteries are critical to preventing blackouts since they will result in mothballing of other infrastructure indicated the utility was budgeting for a 5 year lifespan on the batteries.

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