As a side note, since the article also mentions that:
Since 1/10 Austria and Germany are not in the same energy zone anymore, the pricing zone was split up. This was done because too much renewable power feeding in at near zero cost in Germany was flooding the markets and pushing too much strain on the grid. Heavily needed power lines weren't built because people were protesting.
So the first week has passed were the zones are actually split up and we can see that energy prices are way higher in Austria than in Germany, see [1]. Sure, a more definite answer would need to look at a longer time span. The highest difference actually was on 3/10, where baseload in Germany was 18.29 €/MWh compared to 60.40€/MWh. And peakload on 3/10 was 17.13 €/MWh in Germany compared to 65.83 €/Mwh in Austria. Solar generation on 3/10 in Germany was 12.5 GW!
So far good for Germany, since they anyway subsidize solar and wind heavily and now have the low prices more or less for them self (not totally because cross border capacities, [4])
I haven't looked so far in the costs of the auxiliary energy, really curious how they develop. Germany has in total probably around 385 MW in battery storage already [3] and lots of battery storage projected for 2019.
What everybody misses is the different need during the spikes due out the day. In the morning and at noon the grid needs for a short time a massive amount of energy, which can only be provided by such "pump batteries". That's why Austria can sell this peak energy at much higher prices. On the other side the new northern german wind energy cut the prices dramatically on the non-peak hours.
My idea on this was to use the batteries of the new electric cars to store energy and take it for the peaks. This would need cooperation with the carparks of the big companies to provide free battery loading during the day vs sucking off peak voltages in the morning and at noon. In the late afternoon the battery must be full, what happens in the morning and at noon is for the grid. This solves the electric car problem, and the grid problem with not enough north-south lines.
That kind of integrated approach--with vehicle-to-grid power flow alongside more general coordinated charging--could have clear advantages, especially given the possible growing pains from uncoordinated charging.[0][1] V2G isn't a new subject; it's been around for a while now, and the UK even announced a large research grant on the subject earlier this year.[2] Most of that research looks at V2G in terms of how it can be used to help mitigate the impacts of EV charging in particular and short-term spikes associated with them, rather than say general grid storage. So it's more of a longer-term matter, than the immediate concerns of building out storage capacity.
One of the biggest difficulties is going to be dealing with the economics of battery degradation. You can limit the pull on any given battery to somewhat lessen the impact, but doing so also limits V2G's impact on the grid. Presumably, utilities would pay for battery usage. If so, how does that affect the economics: I can't say either way, but I'd expect the marginal cost of 'renting' EV batteries to be greater than just buying your own for dedicated storage.
1. Near instant response for peak demand fluctuations (e.g. half time during major sports events).
2. Bootstrapping generator for rebooting the national grid should we ever need to.
3. Grid frequency regulation (keeping that AC at 50Hz)
There are a number of projects in progress to look at consumer side Demand Side Regulation (DSR) to provide the latter two grid services without having to carve out mountains or build massive battery farm like Tesla.
Electric mountain is primarily designed to handle the shortist term electrical demands ie putting kettles on (massive demand spike) during tv breaks for the most popular TV programmes. Fortunately the video recorder and subsequent personal recording technology and internet streaming on-demand helps to lesson the demand on Electric Mountain which is why we may never see another one built in the UK. However our demand for technology is driving up the need for more Nuclear and to a lessor extent coal fired power stations, but the ARM cpu is helping to play its part in reducing energy requirements as will parallel processing to mitigate the need for super fast AMD64 cpu's.
Base line demands are met (in order of scaling up or down to meet demand) is nuclear, then coal, gas, hydro including electric mountain. Electric mountain pumps the water back up when surplus electricity is available during the night.
During the week in Feb 2018 when the Beast from the East hit the UK, the realtime gas price on the energy market went off the scale. As more evidence and awareness stacks up that we are going into what is dubbed the Eddy Minimum (a grand solar minimum last seen some 500years ago), so people will take more steps to have a certain level of redundancy built into their homes (where possible LPG/OIL tanks on their property) in order to help mitigate extreme weather events.
Currently if everyone were to live a US lifestyle we would need 4 planet Earths, a UK lifestyle 2.5 planet Earths and so on.
"the video recorder and subsequent personal recording technology and internet streaming on-demand helps to lesson the demand"
Demand may be getting more stable, but supply is going in the other direction! There is a need for energy storage as the UK grid moves to more renewable and intermittent energy sources, predominantly wind.
Pumped hydro stations like Dinorwig can help lessen the need for fossil-fueled thermal power plants to provide spinning reserve / frequency maintenance. So can batteries.
Whether we will see any more pumped hydro built in the UK probably comes down to cost and environmental concerns, when considered relative to other storage technologies like batteries and electric vehicles with V2G.
> during tv breaks for the most popular TV programmes.
Maybe staggering the schedules of TV programs to even this out would be a great idea. After all, now that most people get their tv signal via digital cable rather than over the air, this should be a lot easier to implement. Even +-5 minutes might smooth out those spikes quite a bit.
spoiler: not remotely possible to scale large enough for total world needs.
"If we drained one meter from every upper lake, we would get 54 billion kWh of energy: about a sixth of the target capacity. If performed over seven days, the flow would be 375,000 cubic meters per second, or 125 times the normal flow over the falls."
"We would need 10,000 Raccoon Mountains to meet my baseline energy capacity"
> spoiler: not remotely possible to scale large enough for total world needs.
Yeah, not with those assumptions.
Storing enough energy for 7-days worth of zero-sun and zero-wind is going to be basically impossible across all known energy storage technologies. We'll likely have to run peaker plants during such an extended outage.
But we're not even trying to solve the 7-days worth of energy problem. We're starting with: lets save 3-hours worth of energy, so that the 6pm sun can be used for air-conditioning until 9pm or so.
Which we're not at yet (see the "Duck Curve" or "Nessie curve").
Besides, being able to store energy for 1 or 2 hours is still SUPER useful. Wind is strongest at night, while Solar is strongest during noon. Having energy at dawn (sun isn't strong yet) or twilight (sun is setting, but the wind hasn't picked up yet) is going to be a huge portion of our future energy strategy.
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A huge part of the problem can be solved behaviorally and economically. We can change the price of electricity based on how easy it is to produce. 12:00 noon (highest sun power) can be cheaper, and 3am power (max wind energy) can also be cheaper.
Night-time energy can be used to power electric cars. 12:00 noon power can be used for factory work and other high-energy tasks (Air Conditioning, Washing Machines).
We all can change our behavior to reduce our energy demand between 5pm and 8pm, to reduce the Nessie curve / duck curve. And we can use economics to set the price higher to encourage others to follow our lead.
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Throw down a bit of nuclear, and keep a few natural gas peaker plants active for emergencies, and I think we've got a strong future for energy.
At the end of the day: Pumped Hydro is the ONLY GW-hr solution to this energy storage question. CAES is hundreds-of-MW-hrs, while Lithium Ion is also only hundreds-of MW-hrs.
That's just how the cookie crumbles: we don't have any other technology to store GW-hrs of energy.
Thank you for pointing that out so I don't have to. He's tossing an insane requirement in there and hoping you don't notice. So instead of needing storage to shift about 20-30% of power needs on a daily basis he claims an absolute requirement of 700% of daily usage. Making any solution 20-30 times more costly.
Consider the alternative, as we have snow days. We could have 'energy days' where non-essential demand gets cut off and we fire up some combined cycle plants.
Also I'm not wading through his website again but last time I looked he was studiously ignoring thermal storage. Running that calculation is pretty easy. But he doesn't. Because it's doable even with his deranged 7 day requirement.
"being able to store energy for 1 or 2 hours is still SUPER useful."
Of course, which is why variable minute-by-minute pricing of electricity can serve as a "battery". The air conditioner, for example, can cool the house to the lowest comfortable temperature while power is cheap, which will then act as a zero-cost "battery" when the electricity gets more expensive in the evening.
Someone I know in Arizona says a lot of people crank up the air conditioner in the morning and early afternoon and then just coast through late afternoon and evening. Basically using the house's thermal mass as a 'battery'
I bet a lot more people would do that if electricity was cheaper when the sun was high and more expensive when it was lower.
I'd certainly do that.
In fact, if I was designing a house under such a regime, I'd design it to incorporate lots of thermal mass within the envelope of the house to make it more effective.
What I noticed when looking at this stuff is 'green building' codes are really about green washing natural gas and expensive toxic high R value insulation. Last thing I saw before I stopped researching was an article where and industry shill was crowing that they'd closed the loophole that allowed builders and home owners to use solar energy to offset insulation requirements.
The loophole was centered around, instead of spending $50,000 to install thick foam insulation with it's attendant issues with mold. Install $20k worth of solar panels, a heat pump and thermal mass inside the house.
which doesn't support mold. I've been very pleased with it. My house is shaded by large trees, so solar would never pencil out.
I'm just kinda sad that my idea of concrete "batteries" with variable pricing never gets any traction. People just can't seem to get past the notion that consumer electricity rates must be constant 24/7 despite enormous expense to make that happen.
People just can't seem to get past the notion that consumer electricity rates must be constant 24/7 despite enormous expense to make that happen.
Time of Use pricing exists in Portland. But it hasn't been done right. Even the utility itself admits: Time of Use is best if you use most of your electricity late at night or on weekends. If not, you will not benefit from this plan.
So, unless you want to charge an EV at night, or have "concrete batteries", variable pricing here is dumb.
When I discussed the perverse pricing with someone here whose job is literally to promote EVs, that person agreed, saying more or less: "Yeah, I looked into this for myself. I might be able to save $5/month and I might have to pay an extra $35/month."
Current fixed price electricity here is 7.2 ¢ per kWh. (plus other charges such as distribution cost).
Switch to time of use and pay 14.6 ¢ per kWh between 6 AM and 3 PM, and again between 8 PM and 10 PM.
At the peak between 3 PM and 8 PM pay 20 ¢ per kWh.
The cheap rate is 4.2 ¢ per kWh, between 10 PM and 6 AM weekdays, and all day on Sunday.
Hmmm ... let me see. I can pay 7.2 ¢ all the time ... or I can pay 14.6 ¢ or 20.0 ¢ most of the time ... and get cheap prices when my demand is lowest.
Fixed price is a no-brainer decision for most people. They don't give a fuck about the "enormous expense to make that happen"; most people will choose the plan that costs them less per month.
I mean, its not my argument. But... something like the Dust Bowl of the 1930s or even a large volcanic eruption (like the 1980s Mount St. Helen eruption) would block out the sun in a local area for multiple days.
But my point being: such disasters are beyond our storage capabilities by several magnitudes. Most energy storage projects are at best, aiming for a few hours of energy storage.
Many (ie: Flywheels, typical Batteries, etc. etc.) are aiming for minutes, or even just seconds of grid-energy storage. This idea of days-long or even a week-long energy storage is just devoid from reality.
Extreme north or south. Barrow Alaska gets over 60 days without sun in the winter. A bit further south in more populated regions you only get a few hours of sunlight during the shortest days of the year.
A far more serious consideration for solar is the changing seasons, especially at non-tropical latitudes. I graphed the output of my solar panels (56 north, Scotland) and it's really apparent: https://flatline.org.uk/daystats.html
So those panels are basically useless for 3 or 4 months of the year, i.e. November, December, January, February.
Would there be much improvement if you could tweak the orientation to match the seasons? E.g. tilt them down toward the horizon during the winter?
It's certainly a huge complication to have motorized panels that move all the time to track the sun. But maybe it wouldn't be that much of a hassle to go out there and manually reorient them (just in 1 axis) a few times a year?
They're fixed to the roof, so making them movable would be a risk to their safety and wind resistance while being fairly difficult to access (and ladders are dangerous). For a fairly small benefit. It's not just the angle but the sunrise and sunset are a lot closer together.
Isn't that about covering for outages? Those may never be solved.
This article was about storing off-peak green energy for peak usage. We're talking only about an hour or two of usage? Not 7 days. Those number may pencil out very well.
The interesting thing here is the hint about double taxation; apparently this pumped storage facility pays fee when it ingests mWh to store, and again when it releases them for use. According to the article, that scares away investment in upgrading the facility.
The Bloomergites certainly have the chops to unravel and explain this corner of utility economics. Wish they'd do it! The smart-grid future holds all kinds of energy flows into and out of storage. Storage can be characterized in a bunch of ways.
* Total energy capacity (mWh)
* Peak discharge rate (mW)
* Rampup time for discharge. Rampup is most of the content of this article. The 100mW Tesla-built Hornsdale Power Reserve in South Australia has a subsecond rampup time, which makes its energy very valuable for short periods of time.
* Local efficiency (mWh discharged / mWh ingested)
* System efficiency (mWh at source / mWh at sink, counting transmission loss. The lines up to a mountain dam and back down have losses).
* Money efficiency. Taxes, fees, etc.
* Peak ingestion rate (mW)
* Rampup time for ingestion
* Capital cost (please include externalities like decommissioning and disposal costs)
* Expected lifetime (pump storage lifetime is very long)
* Operating cost
The future smart grid needs a finely tuned balance of capacity, rate, and rampup time to succeed.
Pumped storage is a great idea for places where the topography will work with it. But it's expensive to build new. The multi-hundred-million dollar costs of building a new pumped storage facility might be compared to the new costs of building a massive gridscale battery (what Tesla did in South Australia). I'm hopeful that liquid metal/flow batteries designed for grid scale sized applications will become economical in a $/kWh stored rate. There's a lot of applications for batteries which are too big/bulky/dangerous/hot for domestic use or vehicle use, but are perfectly suited for deployment in an electrical grid application.
Electrical grid operators are already really experienced with the process of building substations, basically get a square or rectangular plot of land, level it, put down concrete pads for transformers and switch gear, cover the rest of it in gravel, erect fence with barbed wire around the perimeter. Now do the same but add more concrete pads for big, 20'/40' container sized batteries.
Pumped storage is a great idea for places where the topography will work with it.
Don't forget NIMBY.
About 56 years ago the utility for New York City wanted to build a pumped storage plant about 30 miles north. It was vigorously opposed and eventually defeated.
Why should people who live in pretty rural areas sacrifice their quality of life to help those who live in a crime infested, filty concrete jungle? That's a bit hyperbolic, but that's what NIMBY boils down to.
For the curious there is an ongoing construction of such pumped-storage in the canton of Valais in Switzerland. It is called Nant de Drance [1] and is located at the Emosson Dam, between the "Emosson Lake" and "Old Emosson Lake".
Carter's dam in Georgia has been operational since 1977 doing pretty much the same thing. Pretty sure the idea has been around for ages but with solar and wind power needing storage it might see more use. The one consideration is that recent environment trends have been against dam building in some areas and even to the point of removing them.
This is really interesting. I spent last night calculating a small solar setup for my property. I have 4x220w panels, 4x100amp deep cycles, and a few inverters: one 1000w, and another 600w. And a 20 amp solar charge controller. Basically the most minimal setup.
I was trying to figure out how to design a system that, given 4 hours of full sunlight at the maximum output of the solar charger (300w) or 4 * 300 w = 1200w total daily charging of my deep cycles. If the system is 100% efficient (it isn't), this gives me 50w a hour over a 24 hour period. 1200w / 24 hr = 50w. But my solar panels exceed the ability of the charge controller. How can I use that to my advantage? I have a well and a holding tank. I was trying to figure out a circuit, perhaps an Arduino program/circuit, with voltage/amp sensors and relays to do this: If there is enough sun, charge the battery. If the batteries are full, turn on the well pump into the holding tank (there's a pressure switch to turn it off when the tank is full). And put the holding tank up on the hill -- which should give me 25-30psi (up 45-50ft). Then I was trying to figure out how to optimize my well pump, or use a DC motor. I might look into salvaging a 2hp DC motor from a treadmill and retrofit it onto a pump housing. Anyway I am trying to optimize for extreme budget. 50w an hour isn't a lot, but it is enough to run a few light bulbs and my tiny refrigerator. I might be able to run a RPi and charge some 18650 batteries for flashlights.
Why not buy another 20amp charge controller, they are like $20?
I ran into similar problems when I was trying to make my own solar AC this summer. I found the best solution for a budget build is to use used panels. Instead of being able to afford 1 I could get 3. Now I have enough power to charge my battery fully and run the AC.
Hey, man, can you drop me an email at robbpseaton at gmail dot com? I have some questions about what sort of initial structure you'd choose to build on your land if you were to do it all over again. I'm interested in doing something similar.
A similar example - San Luis Reservoir in California consists entirely of pumped water. Its main purpose is to act as a regulator supply for the state's aqueduct, but to offset costs the operators do the same trick of generating electricity during the day, and replenishing the reservoir at night.
There are times when this is not practical, but when it is it helps to defray operating costs.
I am curious how much of an effect evaporation has on the efficiency of these systems. You spend energy pumping the water uphill, then it literally vanishes and that energy is wasted. I would imagine that in a hot climate like the one Hoover Dam is in, evaporation would be a non-trivial issue should they go through with the retrofit.
I think that is backwards. In hot climates, like where the Hoover Dam is, I'd expect that evaporation would have no almost no effect on efficiency. It is cold climates where it might be an issue.
The water flowing into the top reservoir of these systems from higher up in the mountains should be able to make up for free for the water lost to evaporation. (If there is not sufficient flow to allow that, then you are going to have a hard time keeping a full reservoir there in the first place).
Evaporation should only be a problem when a system does not have free water from a higher source. I'd expect the most common reason for that would be in cold climates where for part of the year the water that would run down and replenish evaporation is stuck as snow or ice up the mountain.
When you pump some water back to the higher reservoir from the lower reservoir it will raise the water level in the higher reservoir, but probably won't raise the evaporation rate significantly, for the evaporation rate is a function of the surface area, and if the walls are steep at the water level the surface area won't change much.
The only evaporation that should be counted against the water you pumped up is the extra evaporation due to that minor change in surface area.
I assume evaporation is gonna be below an inch a day in even the most hot and dry climates. Considering the total height of the water column it's negligible.
I'm not disagreeing, but wouldn't you need to compare the total volume lost to evaporation to the total volume of water pumped (== cost) to have a sense for whether it's a significant factor?
Its hard to build up a casual sense for how much water is lost to evaporation in most lakes we have experience with because the lake's level is based on geography (level of the outlet) when there's a source of water coming in to replenish it. It could be a larger factor than we think.
That said, I expect that the efficiency losses in the pumping and generation steps would dwarf evaporation. Any storage system has some losses; the ability to store larger volumes makes up for efficiency disadvantages compared to things like batteries might have.
I wonder if evaporation is offset entirely by water that naturally flows into the reservoir. The graphic on the page seems to indicate that there is always a small amount of water flowing down through the system regardless of whether any uphill pumping occurs, which would indicate there's always a surplus of water.
The challenge with energy storage is the tradeoff between cost and efficiency. On the one end you have batteries that are hella efficient but expensive, and then you have a spectrum going Hydrogen -> Pumped Energy -> Compressed Air (cheapest and least efficient)
The question is whether we can build enough wind or solar power that doesn't just meet our needs when it's outputting well, but overshoots them by like 500% so we can use cheap and inefficient energy storage.
I guess enabling individual homes to generate/store energy needed to run their home is more scalable than these so called huge beautiful batteries. But for now, they are good and buy time for innovations in home batteries.
A very simple, zero-maintenance, low cost "battery" for storing energy in the home is a chunk of concrete. When power is cheap, heat/cool the chunk. When power is expensive, blow air over the chunk to extract the heat/cool.
Such a "battery" could very easily keep the house warm or cool at night depending on the season.
What's required to make this work is to vary the cost of electricity to the consumer, which will incentivize such solutions.
That's actually one of the points discussed in the article. Investors don't want this to be a temporary solution. Like the Hoover dam system, this should last a century. But they need the economic incentives to be higher priority than home solar storage.
Sounds like energy arbitrage using physics. I love the idea. I wonder what it will look like in a decade when its adopted more or will it go away when chemical battery storage is cheaper and renewable energy is more efficient.
The difference (or perhaps not) in this case is that it's phenomenally inefficent, requires (and in the process of creation, destroys) unique geography, and isn't viable in many places due to fresh water shortage.
Pumped Hydro is actually pretty awful. Compressed air might work for home needs but will never service industrial needs. Let's hope that a better chemical battery based on sodium and carbon is a reality soon (https://phys.org/news/2018-09-high-capacity-sodium-ion-lithi...).
I don't understand that at all. If you're generating more than you're consuming, then you lose 100% of everything you can't store. Which means 0% efficiency past some point!
But "the round-trip energy efficiency of PSH varies between 70%–80%, with some sources claiming up to 87%."[1]
That's not as good as batteries, which are probably better than 90%, but it doesn't seem bad at all when compared to 0%.
IMO your other arguments are much stronger. Bad to destroy unique geography. Not viable in many places, whether it's because of no water or because of bad geography.
I'm quite skeptical of that 87%, because it's almost exclusively a question of how the energy was generated and odds are, it was generated and shunted from fossil sources that don't have that efficiency. So even by that metric it's 87% of whatever engine you used to make the energy for the pumps.
Whereas even bad batteries have 99% efficiency even counting discharge loss. The problems with those are that they rely on relatively rare metals associated with conflict regions, hence my hopes that we reach a sodium-based battery that will have similar properties to lithium.
it was generated and shunted from fossil sources that don't have that efficiency
Ahhh ... you raise an interesting point which I don't recall reading elsewhere in this discussion (but there may have been new comments posted since my previous pass thru the discussion).
A newly built natural gas plant has an efficiency of perhaps 60%[1]. Recently completed nuclear plants, such as AP1000 based in China, have an efficiency of about 34%.[2]
That's 60% or 34% at the source! There are additional losses from that point forward, whether the energy goes to run pumped hydro or is simply stored in batteries until needed.
Most of the energy that goes into pumping water uphill can be recovered when the water is released downhill through the turbines. Existing pumped-storage hydroelectric plants have efficiencies around 70~80% which is way better than half.
Besides, you get free power if your upper reservoir naturally gets a lot of inflow or precipitation :)
Also Lithium ion battery have a fairly fixed ratio of capacity and power, of about 1MW to 1MWh. That makes them expensive for storing large amounts of power. With pump storage you're much more flexible, just build bigger reservoirs. very large pump storage assets can be optimized even seasonally.
With physical energy storage you also don’t need to worry about the environmental effects of lithium nor do you need to worry about charge cycles sure some maintance is required but the majority of the cost is going to be in the reservoir and that can stand for centuries.
You need a lot of land and specific terrain; still water isn’t carbon neutral(!); and the nature of the things means that if it suffers structural failure the death toll makes nuclear accidents look like almost nothing.
" if it suffers structural failure the death toll makes nuclear accidents look like almost nothing"
You compare a hypothetical dam disaster, with nuclears record so far - its clearly worth reconsidering that comparison.
Nuclear plants also consume large amounts of water, and other resources so could not be considered carbon neutral by your own measure.
Reservoirs are large lakes, creating them entails ecological disruption but not consumption or degradation in the long term.
Not sure where this comparison is going? One dam disaster (Banqiao Dam) caused more death and destruction that almost all other disasters combined. In fact failure of nuclear plants has had remarkably few verifiable deaths.
And compared to the energy one nuclear plant produces, dams seem to have vastly worse death-per-benefit statistics.
Damming a river can cause ecosystem collapse downstream. That's degradation, as I understand the word. And its definitely long-term.
Nuclear proponents always point to the Banqiao Dam disaster, and it's always a misleading argument because that dam was built to control downstream flooding as well as provide power and its failure was probably attributable to how the flood control aspect was mismanaged - by holding back too much water for too long out of fear of downstream flooding, they ended up overfilling the reservoir. If China hadn't bothered with hydroelectric power, the dam would still have to have been built and all those people would still have died when it failed, you just wouldn't be able to use their deaths to make nuclear power look better. (Also, nuclear power didn't exist back when that dam was put into operation, and given the quality of engineering that went into it that's probably a good thing.)
I hoped merely pointing out that discrepancy would suffice - how ben_ws comment compared the history of nuclear accidents to the potential dangers of dams.
Potential scenarios are very important in determining probabilistic risk. Simply showing "it hasn't happened yet" is not a valid way to assess risk. This is the reason it costs more to build and keep nuclear plants safe, than it does dams.
"""Its failure in 1975 caused more casualties than any other dam failure in history at an estimated 171,000 deaths and 11 million displaced."""
Though I could also be talking about the 2,209 who died in the 1889 South Fork Dam incident. (“””Blamed locally on poor maintenance by owners; court deemed it an "Act of God". Followed exceptionally heavy rainfall.”””)
Or the 423 in Malpasset dam, France, as recently as 1959.
Or the 238 in Canyon Lake Dam, 1972.
Or the 1,800 to 25,000 (estimates vary) in the 1979 Machchhu dam failure.
But the one referenced as an example in your original post DID fail - and you wrote "IF it fails". You described a potential failure "in the nature of the things".
It is natural to consider the nature of things - apply equal consideration to nuclear power and your comparison will be more valid.
Interact candidly - don't avoid your error while trying to parse.
You wrote "IF it suffers failure..." so the "it" was not the example of failure you gave, "it" was hypothetical . This is why I asked you what "it" was - not so that you could elaborate on what you could have been talking about, I asked to give you a fair chance to realise "it" was yours to define - a hypothetical dam, one defined only by "the nature of things" and a "death toll makes nuclear accidents look like almost nothing"
Stored hydro & nuclear solve entirely different demands. Nuclear's core strength is providing a strong, reliable, but relatively constant base-line.
Wind/Solar can supplement (or even replace it) depending on costs and geographies, but their generation can be very spiky, and you don't get to pick the spikes (or troughs).
Stored-hydro rounds off the trifecta by providing spikes on-demand, but also by absorbing over-production from other sources.
Nuclear looks wonderful in a "spherical cow" calculation, but the reality is that nuclear strongly prefers a constant production, but demand is never constant. Under-production is obviously undesirable, but over-production is no easier to deal with.
So it's not really about which is better - it's balancing the weak points in each system against the strengths of the others.
When I was in the generation industry we called these base and peaking plants. The 5 nuclear plants were base loaded, a portion of the fossil plants were the load following units then there were the required number of spinning reserve plants. These spinning reserve plants, which are running and using fuel but not producing electricity are what utilities would like to replace first.
Lithium batteries are considerably less carbon neutral than physical energy storage when you account for all the energy needed to mine, produce and repurpose them after they fail.
While dams have failed in the past if built right they can last for centuries.
Also unlike batteries where the majority of the cost sunk is in the batteries themselves with physical storage like this the majority of the cost will be in the construction itself which means that as better pumps and turbines become available you can upgrade your system at a marginal cost.
There was an article some months back about a concrete block lifting system that could be used for a similar purpose, but obviously a lot more compact and lower capacity.
Since 1/10 Austria and Germany are not in the same energy zone anymore, the pricing zone was split up. This was done because too much renewable power feeding in at near zero cost in Germany was flooding the markets and pushing too much strain on the grid. Heavily needed power lines weren't built because people were protesting.
So the first week has passed were the zones are actually split up and we can see that energy prices are way higher in Austria than in Germany, see [1]. Sure, a more definite answer would need to look at a longer time span. The highest difference actually was on 3/10, where baseload in Germany was 18.29 €/MWh compared to 60.40€/MWh. And peakload on 3/10 was 17.13 €/MWh in Germany compared to 65.83 €/Mwh in Austria. Solar generation on 3/10 in Germany was 12.5 GW!
So far good for Germany, since they anyway subsidize solar and wind heavily and now have the low prices more or less for them self (not totally because cross border capacities, [4])
I haven't looked so far in the costs of the auxiliary energy, really curious how they develop. Germany has in total probably around 385 MW in battery storage already [3] and lots of battery storage projected for 2019.
[1] https://www.epexspot.com/en/market-data/dayaheadauction [2] https://www.eex-transparency.com/homepage/power/germany/prod... [3] https://www.powerengineeringint.com/articles/2018/03/battery... [4] https://www.entsoe.eu/data/map/