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'No-water' hydropower turns England's hills into green and pleasant batteries (rechargenews.com)
77 points by geox on Aug 19, 2023 | hide | past | favorite | 79 comments



From their patent [1]:

> the working fluid is a slurry comprising a suspension of mineral particles and a surfactant in water

[1] - https://patentimages.storage.googleapis.com/c5/20/54/6005371...


So the article is wrong in multiple ways. Not only is "no-water hydropower" a contradiction in terms, but when you look into it, it is in fact using water. This is the status quo for science journalism, unfortunately.


There's discussion of something to stir both reservoirs to keep the mineral particles from settling. Which seems rather energy-intensive and wasteful.

There's no specification for what kind of minerals or surfactant, or what kind of properties they'd need to have. No discussion of how to pump an abrasive mixture without lots of expensive maintenance. It, frankly, sounds like they're saying "sand!" What happens if the surfactant leaks or there's a dam break? The scale of disaster from something like this is pretty insane; they're proposing what amounts to a ready-made mudslide behind a dam.

There's also discussion of using the water to cool the generators, like that's somehow novel...and for some strange reason, heat pumps and geothermal heatsinking?

This feels like patent trolling. It reminds me of crazy-board-of-string-and-photos meme guy. "OK, so we have a hydropower plant! BUT, BUT, we put SAND in the water! And and we need some things to stir the water to keep the sand in suspension. We can tack on this geothermal well! And cool the pumps with the water!"


> This feels like patent trolling.

Wouldn't that require that the patent is not only trivial but also useful? Whom would they want to troll with something that is useless?

Might just be looking for an investor to throw money at them, a patent probably helps with that.


It's the status quo for any kind of journalism. Read anything you either do for a living or have life knowledge or education about, and the credulous BS just leaps off the page. Pick any controversial issue, do some research on it, and you'll realize how much "common knowledge" is misinformation due to crap media coverage.


I think good journalism still exists, you just need to pay for it. I don't see the Economist getting basic facts wrong, even in topics I'm familiar with. The main problem is that there is far more money in ad-driven content than high quality subscriber content.


I wonder how stable that suspension is? I can imagine it would be quite disappointing to try and make power and to have some water come down, leaving you with a silted up storage tank.


I have to imagine building 2.5 swimming pools worth of water storage is cheaper than filling a single swimming pool with a heavy liquid. They typically go for $100-$1000/kg, with the non-toxic ones of course being the more expensive.

No idea what the article is talking about wrt being able to utilize lower heights, as the amount of power you can get from a certain drop is independent of density. Higher density decreases the size of the pipes and turbines, so there is a potential economic benefit, but it doesn't change what locations are viable.


>They typically go for $100-$1000/kg...

I was doing some searching, but was unable to pin down precise numbers for industrial water rates, but I am seeing something in the single dollars ($3-8) per thousand gallons.

Assuming I did not bork my conversions, at $5/1000 gallons, that would be roughly $0.001/kg for water. So, a novel heavy liquid priced at the whole dollars per kg sounds like an enormous capex for a large installation when it could use water instead.


The article mentions their plan is to bury the tanks. That is stupid expensive, and one of the reasons existing water storage tanks are never buried in the US.


Buried water storage tanks are not rare. The San Francisco Water Department has some in their system.[1][2] They're basically roofed concrete reservoirs. Those store clean, processed water.

Those could have been fully buried or hidden, but, being visible only from the air, it wasn't worth it.

[1] https://earth.google.com/web/@37.48236017,-122.3128578,104.7...

[2] https://earth.google.com/web/@37.53843703,-121.85711496,126....


That's easy and cheap per volume: Drill a small hole into a mountain. Add a nuke.

It's not for water suitable for consumption, but it doesn't have to be.


Just nuke a mountain, that'll solve climate change. Peak HN.


I'm imagining two connected olympic swimming pools, at the base and on top of a mountain, filled with liquid mercury...



Voila! Three connected pools, none of them Olympic or at the top :-)


That’s not to far off something you’d see in Zelda, Zora’s domain.


> heavy liquid. They typically go for $100-$1000/kg

This company has their own proprietary heavy fluid called R-19. Their formula isn't public, but presumably they understand the success of their company depends on it being affordable.

> No idea what the article is talking about wrt being able to utilize lower heights

It means that, if pumped storage starts to look worth it to you (given budget, etc.) with tanks of size V and a height difference of H, then with their system it might be worth it if the tallest hill available to you is H/2.5.

Or you can keep the height the same and reduce the volume. Or keep both the same and increase the storage. The point is that they claim to offer a better trade-off.


> This company has their own proprietary heavy fluid called R-19. Their formula isn't public, but presumably they understand the success of their company depends on it being affordable.

That assumes they plan to ever deliver anything real. There are very few substances cheaper per unit mass than water, and I would not take on faith that something that isn't even being mass produced yet could ever possibly compete.

> It means that, if pumped storage starts to look worth it to you (given budget, etc.) with tanks of size V and a height difference of H, then with their system it might be worth it if the tallest hill available to you is H/2.5.

That's not how turbines work. Pressure head is independent of volume.

> Or you can keep the height the same and reduce the volume. Or keep both the same and increase the storage. The point is that they claim to offer a better trade-off.

And I am saying that I do not believe their claim that they offer a better trade off.


> That's not how turbines work. Pressure head is independent of volume.

I'm not talking about pressure head. I'm talking about energy storage. If everything is held constant (reservoir volume, height difference) but the density of the fluid changes, then the energy stored changes. Because gravitational potential energy is E = mgh. And m = volume * density.

But since you mentioned pressure head, if volume changes, it doesn't affect pressure. But if the fluid density changes (and all else is equal), then that DOES affect pressure. That's why if you measure pressure in mmHg you will get a different number than if you measure it in mmH2O. So if you took a pumped hydro storage system and drained the water out and replaced it with denser fluid, the fluid would press harder on the turbine.


They claim they have a fluid. The patent says "minerals", water, and "surfactant." Translation: mud/sand.

I can't help but notice that the name they're using is the same as an insulation material; seems almost purposeful to make looking up anything about it very difficult.

I don't think they have anything and this is just a patent troll or someone trying to pull a fast one on investors. I'd be willing to bet they have a long list of reasons why they can't come up with demonstration unit that is room or building-sized...


It could be something like bentonite/baryte or similar drlling muds:

https://en.wikipedia.org/wiki/Drilling_mud


Drilling mud, however, needs to be at least somewhat viscous, so it will carry rock fragments from the drilling back to the surface.


Sure, but it depends also on the kind of drilling and of the terrain that is drilled, drilling mud is used also when drilling with buckets large holes, in those cases the use is only that of avoiding the collapse of the walls of the bore.

The generic idea behind these supposedly high efficiency reservoirs is to have something that is at the same time liquid enough and much heavier than water, most probably the actual formulation will be a compromise.


The equation for potential energy is U = m ⋅ g ⋅ h, so higher density factors into higher mass (per unit volume) so directly into higher energy storage capacity.


But as they stated it translates into higher energy storage capacity (per unit volume). This translates into smaller footprints as volumes go down, but that’s it. Now, mercury is almost 14 times more dense than water so that’s nothing to sneeze at.


Which generates more energy, dropping 1000 tons of water 100 meters, or dropping 1000 tons of steel 100 meters?

Volume matters for the sizing of components, it doesn't matter for the amount of energy you can extract from a height differential.


There is also craned power generation BTW.. Concrete blocks are stacked with a crane.. They are then dropped to the ground and the potential energy harvested by the cranes motor


Storage tanks are limited by volume, not mass.


Which falls under the category of component sizing. But assuming you have however much mass at a given height, a denser fluid won't let you extract the same amount of energy from a lower height, which is what the company is claiming.


You need to generate enough pressure to run the turbines efficiently. High density means high pressure with a small drop.

A small drop means you don’t need a mountain to build the facility.


Best to open in a private window since they do not let you control cookies.

See also [1]

Short Vimeo video [2]

[1] https://news.ycombinator.com/item?id=26062698

[2] https://vimeo.com/495158864


They do actually open a pop-up to allow selected cookies, although you need two clicks to say No and only one to say Yes to all. The Vimeo video is not rated which requires login.

I'm very curious about the longevity of such a fluid, wouldn't there be issues with evaporation and particles falling to the bottom of the downstream station?


Didn't work for me


Much depends on the fluid. Is it toxic? What happens when (not if) it leaks?


Given they only need to specify two properties of the material (density, and ability to be suspended in water), they should be spoilt for choice; and would be pretty stupid if they didn't pick something inert. This is not like semiconductor manufacturing or something where they need to find a material with obscure properties.

My guess is the main reason for not specifying the material is that they will pick whatever is cheapest locally to each development.


The surfactant might be a problem, but the mineral particles are almost certainly something very cheap and common, like clay.


Question is how abrasive it is and how does that affect the turbines and pumps


The particles would have to be extremely small to not fall out of suspension, so I don't think they'd be very abrasive.

The thickness of the viscous part of the boundary layer in water is maybe 0.1 microns (if the water is moving at 10 m/s). Particles smaller than this would be slowed before striking the surface. If the particles are making the liquid more viscous the viscous part of the boundary layer will be proportionally thicker.


The state of the UK's waterways is atrocious. I'm not really keen on them filling the hills with "fluid", personally.


If the dense fluid is sewage sludge, they may be into something.


> "100MW in storage capacity"

Sigh. A MW is not a measure of storage capacity, it's a measure of momentary power. Do they mean it can store 100 MWh of energy? Or do they mean it can generate up to 100 MW of power?

Journalists always seem to get confused by this[1], but it's surprising to see "Recharge News", of all people, making such a mistake!

[1] The Times once famously published an entire headline anti-EV article that claimed the UK would need to build dozens of new nuclear power plants to power them. But it quickly turned out they had just gotten GW and GWh confused!


Most here probably won't need this but: the Watt is a unit of power. Power is the rate of energy consumption. An amount of energy, over an amount of time. 1 Watt is 1 Joule per second. The "over time" is literal: 1 W = 1 J/s = 1 V*A/s. 1 watt, is 1 joule per second, is 1 volt-ampere per second.

An analogy to motion: joules are distance, watts are speed, and watt-hours are like light-years.

The amount of energy consumed, if you have one watt of power for a certain amount of time, is the confusingly-named Watt-hour, or Watt-year, etc. 1 Watt-second is 1 Joule. 1 Watt-minute is 60 J. 1 Watt-hour is 3600 J.

I'm not really sure why the Wh exists, other than to let you easily estimate how much it costs to run an appliance for once hour. It tends to confuse.


> I'm not really sure why the Wh exists

It never really clicked for me how silly this is until you said it, so I went and looked it up.

It turns out it's kind of the other way around; the watt came first: It was originally defined as "the power conveyed by a current of an Ampère through the difference of potential of a Volt".

Watt-hour seems to come around in the 1890s as utilities explore ways to bill customers for electricity use, originally "ampere-hour meters" and then "watt-hour meters".

Joule shows up about the same time, in like 1880 or so, and was defined in terms of the watt, rather than the watt defined in terms of the joule, if I skim Wikipedia correctly.. So that'd mean Joule and Wh are both kind of competing units of energy - one used by GE and Westinghouse and all those people, and the other used by scientists(?)

The watt then gets redefined in terms of a joule much later, in 1948.


> Watt-hour seems to come around in the 1890s as utilities explore ways to bill customers for electricity use

Makes sense kwh is an accounting unit of energy not a science unit. I feel that's 'fine'. Tell the accountant that the pump that drains the east shaft runs 12 hours a day at 53kw and they can figure the monthly cost using a ten key.

Hat tip the parent. It's really annoying that Journalists understand neither science nor accounting.


> 1 W = 1 J/s = 1 V*A/s

That last "/s" should not be there.


it's a nice human scale unit - a bit like some countries still cling to inches as a length measure.


Either way, "building dozens of nuclear power plants" is something that should have been done decades ago. Yes, waste handling is a concern for the local environment of a specific area and needs to be taken seriously. But given that climate change is a GLOBAL concern, how much better off would we as a planet have been doing prudent risk management and pressing forward with nuclear power as opposed to listening to the hysterical FUD of people who call themselves "environmentalists?"


> Either way, "building dozens of nuclear power plants" is something that should have been done decades ago.

Great idea. How?

Even China, which regularly builds new nuclear power plants, can't do it at a pace sufficient to keep up with wind power, not to mention renewables as a whole.

I talking here in terms of reported TWh delivered.



"The Nuclear Fallacy: Why Small Modular Reactors Can’t Compete With Renewable Energy":

https://cleantechnica.com/2023/01/18/the-nuclear-fallacy-why...

> "“Small modular reactors won't achieve economies of manufacturing scale, won't be faster to construct, forego efficiency of vertical scaling, won't be cheaper, aren't suitable for remote or brownfield coal sites, still face very large security costs, will still be costly and slow to decommission, and still require liability insurance caps. They don’t solve any of the problems that they purport to while intentionally choosing to be less efficient than they could be. They’ve existed since the 1950s and they aren’t any better now than they were then.”


Hinkley Point C is still not finished.

The problem is not so much the waste, but the "black swan": each plant has a failure probability that's low - perhaps 1/10,000 or less - of a disaster that contaminates a very large area around it. The UK was tracking after effects of Chernobyl, two thousand miles away, for two decades after the incident. That has a negative effect on people's willingness to build new plants.



Your chosen scapegoat isn't plausible. If the issue was just "people who call themselves environmentalists", we'd be awash in nuclear power plants, because societies globally are pretty notorious for not paying much attention to environmentalists.

The real issues are quite different. Environmentalists may have pointed out some of them, but they're just the messenger in that case.


Waste handling is only a problem because of non proliferation laws it’s not a mandatory outcome


Assuming they accurately reported that it is an olympic swimming pool sized resevoir and a height differential of 100 meters, that would only be 1.7 MWh of storage capacity with perfect efficiency.


I think it is talking about power capacity, not the discharge rate.


I work in energy storage. This is not totally wrong, its just omitting the duration. 100MW only describes the rate at which the battery can discharge. The duration would be expressed in MWhours (mwh) so a 100MW/200MWh system would be able to discharge its full tank in 2 hours. You need to know the MWh to know how physically large the system is.


A watt has dimensions of energy over time. It cannot be used to express a measure of energy unless you multiply it by time, as in a watt-hour.


Came here to say the same


More direct / detailed info here:

https://www.rheenergise.com/how-it-works

https://www.rheenergise.com/faq

They have their own denser-than-water fluid called R-19. The formula isn't public. They say it's "environmentally benign" and the ingredients are "common and available".

The viscosity is comparable to milk. They believe they can make mechanical parts (pumps, turbines, etc.) that can handle the denser fluid.

They say the cost is "broadly similar" to regular pumped hydro.


I'm super sceptical of these types of approaches, to the point that I often question some of the weird financial incentives that can cause money to be put into stuff like this in the first place.

Simple physics says that gravity is actually a pretty poor energy storage mechanism (see other fanciful ideas about stacking heavy blocks). Pumped water storage is about the only form that actually makes sense from a cost/energy storage perspective because (a) in nearly all those cases the reservoirs already exist, and (b) you're pumping a lot more than a couple Olympic-swimming pools worth of water. And even then the costs can be giant - LA was looking into a $3 billion project to use pumped storage behind the Hoover Dam a few years ago, not sure what happened with that.

There is just so much "green washing" going on these days, I think it's more important to focus on things we know will work, or improvements to ideas that already work.


People don’t understand the grid energy storage market. Some think it’s only about storing as much energy as possible over as much time as possible. That’s not the full picture. Response time and ability to handle several cycles a day is also very important for many grid energy storage applications.

The stacking of heavy blocks you mention is actually a very decent idea. No, it’s not going to compete with pumped hydro for seasonal storage. But that was never the point. It’s about shifting load a few hours a couple of times every day. Perhaps with some spare capacity to help with a day or two with less power.

We need both solutions. Pumped hydro is not that great for cycling often and rapid response and it’s much harder to find good sites to build it. Big water reservoirs are extremely damaging to the environment. They obviously destroy all land based life on the land they claim, and the constant cycling up and down of the water lever means the conditions for life in the water is atrocious as well.

A fun fact is that for hydro power plants it’s becoming viable to install battery energy storage on site. Wouldn’t think that makes sense would you? By putting some of the power regulation loads on the battery they can run the hydro power plant production more evenly, reducing pressure variations that causes more wear and tear, which increases long term maintenance costs.

Don’t watch those YouTube “debunkers” for insight into these kinds of topic. They rarely do more than 10 min of research. (I know one of them did a video on Energy Vault that always gets shared in these conversations, despite the fact that there’s not a single valid point in the video)


Many hydroelectric plants with a reservoir are already energy storage systems. They can adjust their power output up and down. They can, for short periods, drain the reservoir faster than it is being filled. The seasonal patterns of rainfall, and energy demand, influence how much power a plant can output in terms of peak and average, both short and long-term.

At Niagara Falls, the falls can be diverted through the plants, nearly shutting the falls off. It isn't normally done, for both ecological and sightseeing reasons, but when power was needed after the 2003 blackout, the falls were reduced to about 15% flow: https://www.theglobeandmail.com/news/national/how-the-power-...


The grid needs more than just big batteries it also needs extremely responsive ones. This is why you see flywheels attached to the grid.

https://www.popularmechanics.com/science/energy/a4889/433775...

The total energy stored is relatively tiny, but devices want a smooth electrical signal not just energy from a wire.

Ideally you want an instant response time and GWh of energy storage on the cheap, but that instead grid operators use many different systems to simulate that.


I wonder why the dense liquid? Only to save the storage tank or will it able to generate higher power? Probably both because the potential is proportional to the specific weight of the medium. Pumped-storage hydroelectricity is certainly no novelty.


So something worse than water? It’s not clear what this liquid really is


Essentially pumping a denser-than-water fluid up hill underground. OK. Here in the PNW that is what all these ugly windmills should be doing in the Columbia Gorge.


If only TFA mentioned what is actually in the working fluid...


I found the following quote:

> RheEnergise said it invented the new high-density fluid, known as R-19. Chief executive Stephen Crosher told Professional Engineering that the liquid is a fine-milled suspended solid in water, with low viscosity and low abrasion characteristics. The base material is used in oral medication applications, in a similar way that chalk is used as a bulking agent for pills and tablets. He said the raw materials are common and available, including in the UK, and the fluid could either be manufactured on-site or at a depot. [0]

Maybe someone knowledgeable about oral medication applications has any idea.

[0] https://www.imeche.org/news/news-article/high-density-pumped...


After looking up mining slurry densities limestone is 2.7x the density of water. Calcium carbonate (limestone) is also used for filler in some medications. I'm pretty sure its just limestone slurry.


It is more like that is a sort of drilling mud (bentonite possibly additioned with baryte ):

https://en.wikipedia.org/wiki/Bentonite

https://en.wikipedia.org/wiki/Drilling_mud

Bentonite is also used in medicine (dermatology).


Interesting! I wonder how the economics work out wrt aging of the liquid, abrasion (low abrasion != no abrasion)... and of course how environmentally friendly it is to dispose of.

It seems hardly worth it to use a specialized fluid for "only" a 2.5x density multiplier, on first glance.


I wonder if it's kaolin?


Kaolin apparently has a specific gravity of 2.16–2.68, so it doesn't seem to be dense enough on its own unless the ratio of kaolin:water is extremely high? Good guess though!


My first guess was some form of alginate.


Alginate is probably not as dense as a suspension of kaolin, and also being an ionic polymer, there's no need for a surfactant or dispersant to stabilize it. Also it is probably way more expensive.


An organic compound would not have the density.


Probably just silica? It would be non-toxic and maybe dense enough.




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