No, Heavy Fluid Pumped Hydro Is not Remotely Fairly Or Economically Viable – CleanTechnica – TechnoNews

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A latest on-line dialogue on gravity storage introduced the standard suspects out of the woodwork. Proponents of heavy fluid pumped hydro reared their sludgy heads this time. Comply with alongside for why this can be a foolish thought, as all gravity storage choices that aren’t pushing water uphill develop into.

As a reminder, gravity storage may be very fundamental stuff. The maths is Grade 5. The science is Grade 7. Mass occasions the acceleration because of gravity occasions peak. Kilograms occasions 9.8 meters per second squared occasions peak in meters. Joules are the unit of power this produces, and one million of them is about 0.28 kWh. Sure, Joules are tiny. A ton of mass at 100 meters of peak has about that a lot potential power, so in the event you have been to droop it with a crane with an electrical regenerating winch, you’d get about that a lot electrical energy out of it. Because of this the mere considered suspending blocks of concrete or metal in mid air with a crane would by no means happen to any rational, STEM competent particular person, except they have been venally promoting it to STEM-illiterate lovers with open wallets.

What’s heavy fluid pumped hydro? Effectively, let’s begin with pumped hydro, then let’s go on to the ‘problem’ that heavy fluid pumped hydro ‘solves.’ We’ve been pumping water uphill to retailer electrical energy since 1907. All it takes is a hill, a reservoir on the high, a reservoir on the backside, a tunnel or some actually sturdy pipes, and a few reversible hydroelectric generators. Pump plenty of dust low cost water as much as a extremely easy higher reservoir by means of a tunnel by means of rock with actually easy electrical generators. Whenever you want electrical energy, let the water move again down by means of the tunnel and generators to generate electrical energy.

Hills have been round because the Earth coalesced out of ball of house mud. The primary reservoir was in all probability constructed round 2500 BCE in Egypt. We’ve been constructing tunnels since about 520 BCE, when a Greek tyrant named Polycrates constructed a kilometer-long tunnel to convey contemporary water for the town’s 20- or 30-thousand residents. The primary hydroelectric turbine was in all probability in-built 1882 in Wisconsin, USA, of all locations. This isn’t remotely difficult know-how.

But some folks assume it actually wants enhancing on. A kind of teams are the heavy fluids people. Their considerations are some mixture of an absence of vertical distance, an absence of water, or an absence of locations to place pumped hydro. Let’s begin with the final one.

See all of these dots? A couple of years in the past the Australian Nationwide College and a gaggle of individuals led by researcher Matt Shares did a geographical info system examine. They’d a pc search for all of the locations on Earth for which there was respectable knowledge the place it was attainable to place a few reservoirs inside a small handful of kilometers. They ignored locations with lower than 400 meters of vertical distance between reservoirs (do not forget that peak factor within the fundamental science). They eradicated wherever there was working water, to keep away from messing up streams or rivers. They prevented locations that have been protected areas, principally parks and the like. They picked locations that have been pretty near current transmission strains, so it might be simple to convey electrical energy to and from the reservoirs.

They discovered a quite absurd variety of websites that met these standards. Most of the huge clean spots on the map above are simply locations the place an extremely small variety of folks dwell, and there’s no transmission and even good knowledge units. They discovered 100 occasions the useful resource potential for pumped hydro as the whole quantity of power storage that their examine concluded was required for all decarbonization. If solely 0.5% of the websites, one in 200, pan out, that’s 50% of the issue solved.

There aren’t a scarcity of websites to place closed loop, off-river, pumped hydro electrical energy storage. That’s two of the objections knocked off the checklist, locations to place it the place there may be adequate peak. Oh, wait, say the pumped hydro critics. What in regards to the Nice Plains of the USA, the Prairies of Canada, and the Northern European Plain? These are a subset of the clean spots to the north of the map. Apparently these folks have by no means heard that we are able to transmit electrical energy, or that there’s this factor known as the grid that we are able to have storage belongings on.

This leaves the third standards, having sufficient water. Let’s think about a fairly large pumped hydro facility, one with 30 GWh of storage, about 7,700 Tesla Megapacks, the large grid storage one. Its peak distinction is 500 meters. Its round-trip effectivity is about 80%. It could require round 28 million cubic meters of water. That seems like lots.

How a lot contemporary water does the USA devour day by day? About 1,200 million cubic meters. Do pumped hydro amenities devour the water? No, it simply goes up and down, with a little bit of evaporation requiring topping off. Pumped hydro amenities don’t require a brand new 28 million cubic meters of water on daily basis, they simply play with the water they’ve. 30 GWh of storage requires about one-fortieth of a single day’s water consumption, and doesn’t devour it. That’s about one sixteen-hundredth of the USA’s annual water consumption. When pumped hydro amenities are constructed, typically the builders simply allow them to replenish with rain water, though that’s pretty gradual. Many are definitely replenished with rain sufficiently to require that extra water be fed into close by streams or rivers. Others run pipes or construct momentary channels from close by rivers or lakes.

If you would like extra power storage, simply make the highest and backside reservoirs greater. Larger reservoirs are remarkably simple to construct. They’re the least troublesome a part of pumped hydro. Due to the character of reservoirs as three-dimensional volumes, increasing them 10 meters in all instructions produces non-linear outcomes. Let’s take a easy instance. Suppose you will have a dice 40 meters on a facet. It has a quantity of 64,000 cubic meters. Let’s develop it 10% in all instructions, turning it right into a dice 44 meters on a facet.

Does the quantity and therefore the mass of water it may maintain enhance by 10% to 70,400 cubic meters? No, it expands to 85,184 cubic meters, a full 33%. Double the perimeters of the dice to 80 meters and the quantity isn’t doubled to 128,000 cubic meters however shoots as much as 512,000 cubic meters, a full 8 occasions as a lot water and therefore mass.

It’s a bit troublesome, in different phrases, to determine what downside the heavy fluid people assume that they’re fixing. Are they making it cheaper? Are they making it extra handy to search out fluids? Are they growing the variety of websites with 400 meters of head peak or extra? Effectively, no.

What are they claiming? That by utilizing heavier fluids, they will scale back peak or quantity of fluids, sometimes by 60%. Keep in mind, it’s mass occasions acceleration because of gravity occasions peak. There aren’t any exponents in there, in contrast to with the quantity of reservoirs cubing or wind power swept space squaring or wind velocity energy cubing. The rise of power for pumped hydro by making the fluid heavier is linear. Double the mass of the fluid and also you get double the potential power storage.

If the heavy fluid people have been taking part in with one thing the place there was an exponent, like swept space of wind generators or velocity of the wind, they might be on to one thing. However they aren’t. They’re taking part in with linear stuff, the mass of fluids.

How are they doing that? One proposed technique includes utilizing brine options, that are mixtures of water and excessive concentrations of salts like sodium chloride or calcium chloride and are 10% to 40% heavier for a similar quantity. Magnetorheological fluids, iron filings in water or oil, are 2.5 to 4 occasions denser. Fluorinated artificial oils (40% to 90% denser) and glycerin mixtures (15% to 25%) have additionally been thought of because of their increased densities and steady properties. However nobody is attempting to commercialize any of the above.

There may be one agency on the market which is attempting to commercialize a special resolution, fine-milled solids in a suspension in water. What does that imply? A suspension is a bunch of stable particles floating in a liquid. Depart them alone and so they’ll sink to the underside or float to the highest finally. How dense the ensuing heavy fluid is decided by the combination density system, which is fairly fundamental. These aren’t options, that are like a full jar of marbles that you just add water to with out enhance the quantity of the jar. The stable particles displace water.

They’re asserting that their fluid has 2.5 occasions extra mass per cubic meter as water. Consequently, they will use 40% of the water or 40% of the peak and get the identical power storage. On condition that neither water or peak are remotely restricted assets or notably laborious to take advantage of, this can be a little bit of head-scratcher, however possibly it’s cheaper?

Larger, heavier particles sink to the underside sooner. Larger, lighter particles rise to the floor sooner. Therefore, fine-milled solids, on the dimensions of micrometers or nanometers. There are 1,000,000 micrometers and 1,000,000,000 nanometers in a meter. They’re tiny particles. You may be considering to your self, how will we make particles of stuff that small, and the way a lot does it value? Good query.

Ball milling is a extensively used technique, the place supplies are floor in a rotating cylindrical chamber with metal or ceramic balls, reaching particle sizes within the micrometer vary by means of repeated impression and friction. Jet milling employs high-velocity jets of compressed air or fuel to speed up particles and trigger them to collide, successfully producing sub-micrometer particles. Cryogenic milling cools supplies to cryogenic temperatures utilizing liquid nitrogen earlier than milling, making them extra brittle and simpler to grind — perfect for heat-sensitive supplies. Attrition milling includes grinding materials by friction and shear forces in a mill with rotating discs or arms, producing high quality and uniform particles for varied industrial functions.

Is any of this low cost? Probably not. Let’s begin with the uncooked supplies. The agency in query is coy about what fine-milled stable they’re utilizing of their patented fluid, however they’ve mentioned in public statements that it’s a standard substance utilized in oral medicines, principally a innocent substance that will increase quantity sufficient that sufferers can swallow or swish the energetic elements. The commonest of those is microcrystalline cellulose created from wooden pulp, however its density is way decrease than water.

My first thought was that the key sauce may be silicon dioxide, also referred to as colloidal silicon, generally used as a bulking agent in tablets. The colloidal half is necessary for this. Colloidal suspensions are completely different than non-colloidal ones in a couple of methods, however the important one is that the particles don’t settle out, being high quality sufficient to remain within the combination by means of Brownian movement. Milk is a colloidal suspension of fats globules, casein micelles, and dissolved lactose and minerals, as a standard instance. If a substance isn’t colloidal, all of the heavy bits fall out of the liquid and create a layer of mud on the underside of no matter they’re in.

The utmost for suspended silicon dioxide is about 60%, which coincidentally provides solely a 60% enhance in weight. Silicon dioxide is the densest substance I used to be capable of finding that’s additionally utilized in oral medicines, so there’s a sniff take a look at downside. Its density by itself is 2.65 occasions that of water, however you possibly can solely combine 0.6 grams of silicon dioxide with 0.4 grams of water, and whenever you add the densities collectively it doesn’t come near 2.5 occasions the mass of water.

This means that they aren’t utilizing silicon dioxide, or if they’re, they’re getting the tip mass incorrect. Not getting the fundamentals of physics proper is comparatively widespread for individuals who attempt to outdo fundamental pumped hydro, however let’s assume that they’re competent.

What else may they be utilizing? In all probability barite, aka barium sulfate, which is 4.5 occasions denser than water. It’s extensively used within the oil and fuel business as a weighting agent in drilling fluids. It’s additionally extensively used as a radiopaque distinction agent for X-ray imaging and different diagnostic procedures. That people are given it to drink means that that is what the agency meant, and so they or the folks reporting don’t know that it’s not a medicine, however used for diagnostic imaging.

Do not forget that bit about colloidal suspensions? Barite doesn’t tick that field by itself. Sometimes bentonite is added, a clay which will increase the viscosity of water in order that the bentonite particles stay colloidally suspended. That is generally utilized in drilling. We’ll come again to that viscosity later.

A little bit of serviette math suggests a mix of 5% bentonite and 41% barite in water would have a density about 2.5 occasions that of water, and it might be a colloidal suspension. It’s fully attainable to attain the two.5 occasions mass for a similar quantity that the corporate claims, in different phrases.

What would this value? What does water pumped from a lake or river value? Allow and utilization prices may be a greenback per cubic meter. Pumping it a kilometer prices 10 to 50 cents. Assuming the water supply is ten kilometers away, that turns into per $2 to $6 per cubic meter. A cubic meter of water weighs a ton.

Advantageous milled barite sometimes prices $100 to $300 per ton in bulk per what I used to be capable of finding on-line (not being an individual who operates drilling tools). Bentonite prices about $100 per ton as effectively. Selecting the averages, that implies that 5% bentonite and 41% barite would value about $87 per ton of elements, with 54% water added to make it 100%.

Plain water prices maybe $4 per ton. The colloidal suspension prices about $90 per ton. That’s 22.5 occasions costlier for two.5 occasions as a lot power storage.

What would this do to the capital prices for a reasonably-sized pumped hydro resolution, that’s, one which was price constructing? Let’s take the 30 GWh resolution above. The large declare of the agency in query is about peak, so let’s take the five hundred meters within the instance and divide it by 2.5, giving us a pleasant even 200 meters. The identical quantity of water is required, 28 million cubic meters.

The essential pumped hydro facility would value $3 to $9 billion to construct, a mean of $6 billion. Filling it might value one other $112 million, a fraction of the development value.

Constructing a 200-meter peak facility with the identical dimension tunnels and reservoirs saves a little bit of development prices, however not that a lot. Name it $2 to $7 billion for a mean of $4.5 billion. That’s a saving of $1.5 billion maybe. Filling it with 28 million cubic meters of $90 per cubic meter fluid, nevertheless would value $2.5 billion. A lot for that saving. Add a billion to the capital prices.

Truly a bit extra. The bentonite and barite aren’t going to get to the location free of charge. Let’s assume that they should journey 500 kilometers, 400 of it by rail and 100 by truck. Freight trucking within the USA prices about $0.25 per ton kilometer. Rail prices round $0.04 per ton kilometer. Add one other $700 million to the price. It’s now $1.7 billion extra, about 33% costlier, for a similar power storage.

Is that this a showstopper? Not essentially, though it’s a head-scratcher as to why anybody would pay a full third extra for a similar power storage.

However let’s get again to that viscosity. How way more viscous is the 5% bentonite, 41% barite, and water combination? 50 to 200 occasions extra viscous, or 50 centipoise (cP) to 200 cP. The viscosity of a fluid dramatically impacts its move price, with the move price inversely proportional to viscosity as described by the Hagen-Poiseuille equation. For example, a fluid with 100 occasions the viscosity of water would move at only one% of the speed underneath an identical strain and diameter situations. 50 cP could be 2% of the speed. 200 cP could be 0.5% of the move price.

The facility output of a hydroelectric turbine is calculated by contemplating a number of components: the peak distinction the water falls (head), the volumetric move price of water, the density of the fluid, the acceleration because of gravity, and the effectivity of the turbine. These components are multiplied collectively to find out the facility output.

The dense fluid pumped hydro people are relying on the density of the fluid multiplying power by 2.5. However what’s that one within the center? The volumetric move price? The one that’s 50 to 200 occasions slower than water? Oops. Which means 25 to 80 occasions much less power with the ratio.

So this 33% costlier pumped dense fluid resolution would generate 25 to 80 occasions much less power if used with precisely the identical tunnels or pipes and generators as pumped hydro with water? Can that be solved?

Certain, massively scale up the tunnels or pipes, generators, and pumps. The identical equation that advised us the fluid move can be utilized to determine how a lot greater they must be, and at 100 cP, they might should be 3.16 occasions greater. A ten-meter diameter tunnel for pumped hydro would should be a 32-meter diameter tunnel, and 10 occasions as a lot rock must be eliminated. The quantity of rock that must be supported will increase with the sq. of the diameter. This ends in larger potential for deformation and collapse. A 32-meter diameter tunnel would require much more shoring up than a 10-meter diameter tunnel, so it’s not 3.16 occasions as costly, however in all probability 10 occasions as costly.

Tunnels are 30% to 40% of the price of pumped hydro tasks. The hypothetical $4.5 billion dense fluid pumped hydro resolution would see not $1.1 to $1.3 billion for these tunnels, however $11 to $13 billion. The $2.2 billion extra has all of the sudden turn out to be $12 billion to $14 billion extra. The $6.1 billion fundamental water pumped hydro resolution is now a 3rd the price of the dense fluid resolution.

Is there the rest? Oh sure. Generators are additionally topic to frictional losses. For well-optimized water generators, the losses are round 1% to three%, a part of the general losses of hydroelectric dams and pumped hydro. However they go up with viscosity, lots. A 50 cP fluid has 50 occasions the friction because of the Reynolds quantity within the Darcy-Weisbach equation for head loss, so 50% to doubtlessly 150%, one thing that couldn’t even get by means of the turbine because of friction, simply ooze gently by means of the unmoving blades. A 200 cP fluid would have 400 occasions extra friction, so wouldn’t spin the turbine in any respect, simply ooze just like the sludge it’s.

As a comparability you possibly can latch on to, shampoo has a mean cP of 18. Whenever you squeeze or pour it out of its plastic container, you possibly can see how slowly it strikes, and that squeezing it out takes a bit extra power than if it have been water. It flows 18 occasions extra slowly with the identical strain and diameter of pipe or tunnel. That might lower turbine technology by an element of 18. However that’s not all. Generators don’t like friction, and that 18 cP viscosity comes with plenty of friction. In an ideal world, shampoo, after reducing recoverably potential power by an element of 18, would then scale back it by one other 18% or so coming and going. If shampoo have been as dense as barite-infused water, its two-way effectivity could be underneath 1%.

Barite suspended in water has a viscosity a lot increased than 18%. In the absolute best case, 50% losses with bentonite and barite, it appears. And that’s in each instructions. Which means zero round-trip effectivity with the entire electrical energy put into the system misplaced to inefficiencies.

What a couple of tiny system, possibly 10 MW / 100 MWh, utilizing pipes as a substitute of tunnels? Effectively, the whole capital value could be excessive, however may be within the vary of batteries. However the round-trip effectivity would kill it. A bentonite-barite suspension, which might get to the density necessities, fails in two separate methods to attain its ends.

Not one of the above is remotely troublesome to comply with for folks with fundamental STEM expertise. Actually the nerds I’ve talked with about dense fluid pumped hydro have simply shaken their heads. I imply, it’s not Grade 7 science. Effectively, the cross-section and quantity of cylinders is. Viscosity calculations have to attend till Grade 11 or 12, though the truth that extra viscous fluids move extra slowly is launched years earlier. Civil engineers get the Darcy-Weisbach equation in first 12 months of faculty or college, but it surely’s fully attainable that some excessive faculties introduce it in superior placement course in Grade 12. It’s not laborious, simply not instantly helpful.

The one one which’s remotely superior is tunnel diameter considerations associated to compression and collapse, which is launched sometimes within the third 12 months of civil engineering programs, however is intuitively apparent to anybody who pays consideration to STEM issues. It’s not like I’m a civil engineer, however it’s an apparent concern and I went and located references for it.

Effectively, let’s return to the silicon dioxide 60% resolution. Wouldn’t it be much less viscous? A selected instance is Ludox TM-50, a colloidal silica product with 50% SiO₂ by weight. The viscosity of Ludox TM-50 is roughly 30 cP at 25°C. For a 60% suspension, the viscosity could be anticipated to be considerably increased because of the elevated particle focus. 30 cP, in fact, means it might ship 30 occasions much less power for a similar mass and see 30% effectivity losses in each instructions. 60% extra potential power would flip into vastly much less actual power.

Effectively, what about in the event that they don’t use bentonite, a clay, however a surfactant like polysorbate. It may well create colloidal suspensions of fine-milled barite too. No luck. Whereas polysorbate requires only one% to allow colloidal suspension, it seems, a lot of the viscosity comes from the fine-milled barite, not the additive that permits colloidal suspension.

Is there any manner round this? Certain, warmth them up. At 40° Celsius, colloidal silicon’s cP drops to 15-25, so solely a 30% spherical journey turbine effectivity loss in the most effective case. A bentonite-barite resolution at 40° Celsius would see a greater enchancment with a drop to twenty cP, however that’s nonetheless a 40% effectivity loss round-trip only for the generators. Each are nonetheless shifting 20 to 25 occasions extra slowly than water, so are producing solely 4% or 5% of what water would. Oh, and their density drops, so the potential power per cubic meter drops as effectively.

And to be clear, which means that they should get warmth from someplace. Their patent makes it clear that they’ve figured this out, at the least partially, as a result of pages are dedicated to getting warmth from geothermal or fuel generators in addition to having warmth exchangers and warmth pumps in every single place.

No free lunch. That is thermodynamics. I’ll remind you of British writer and scientist C.P. Snow’s model of the three legal guidelines:

• You possibly can’t win (that’s, you can’t get one thing for nothing, as a result of matter and power are conserved).
• You possibly can’t break even (you can’t return to the identical power state, as a result of there may be at all times a rise in dysfunction; entropy at all times will increase).
• You possibly can’t get out of the sport (as a result of absolute zero is unattainable).

Decreasing viscosity with warmth trades one power downside for one more. That’s thermodynamics for you, an actual buzz-killer at power business cocktail events.

Is it attainable that the agency in query has created a non-viscous colloidal resolution with another fine-milled stable and a few components? Deeply unlikely. Viscosity of a fluid with fine-milled particles is a operate principally of the particles, which have bodily mass. Actually, the finer the particles, the larger the viscosity, and the particles should be actually high quality with a view to be in a colloidal suspension. The properties of liquids are a really effectively mined area. There are high-density, low-viscosity fluids, however they’re issues like chloroform, mercury, and bromine. None of these are remotely wise to make use of because of their various levels of toxicity to people and most different lifeforms. If they’ve magically invented a low-viscosity, high-density fluid that isn’t in widespread use and was low cost, they might be promoting it to the drilling business and presumably choosing up a Nobel Prize.

Whereas I had enjoyable working the numbers and determining what supplies in what mixtures they have been prone to be utilizing, this isn’t just like the gravity power storage system that fracks the identical quantity of shale time and again, crushing it into gravel, grit, and sand, degrading its generators with grit and filling its higher reservoir with ugly grey sand. That one took me an hour of poking at it earlier than the issue grew to become apparent, principally as a result of I had by no means checked out fracking in any element earlier than. The primary time I heard of this dense fluid pumped hydro proposal, the shortage of a cause for it and the issues have been obviously apparent. Quantifying them and determining the sting instances took time, however not realizing that the answer wasn’t viable. And simply as with the fracking resolution, I’m not a hydroelectric engineer, a civil engineer, or an individual who works with dense colloidal suspensions, so it’s unlikely I’ve privileged information.

Keep in mind, the fundamentals of viscous fluids shifting slowly are grade college stuff, whereas the calculations are Grade 11 or 12. Everyone who has ever poured maple syrup, walnut oil, or molasses is intimately conversant in it. Everybody who has stirred liquid honey is aware of it’s lots more durable than stirring water. Tunnels three and a bit occasions wider being ten occasions the quantity is Grade 7 stuff, though them being more likely to break down and pancake something inside them is a little more superior, however nonetheless undergraduate stuff.

So the questions are the identical. Why didn’t anybody ask these apparent questions of the individuals who ‘invented’ this? Why didn’t the governmental businesses which have given them one thing like $15 million ask them how they have been going to get across the fundamentals of fluid dynamics? Why didn’t any of the buyers which have apparently given them a couple of million ask any of this? Why didn’t any of the funding organizations ask individuals who would have the ability to see the bleedingly apparent, like a Grade 11 scholar who simply handed a take a look at that included viscosity calculations, what they thought? Why didn’t any of them have a look at their slowly pouring shampoo and have a weak little lightbulb go on about what it implied about dense fluids and power storage?

Like utilizing cranes to raise concrete blocks as an power storage resolution, after I first heard of dense fluid pumped hydro, I assumed I’d by no means hear of it once more as a result of it might sink with no hint. Sadly, no. Somebody at all times feedback on its wonders after I speak about pumped hydro’s international development price or the failures of different varieties of gravity power storage. A minimum of now I’ll have an evaluation to answer with, quite than a couple of scathing phrases about oozing sludge not being remotely an answer. Maybe it’s going to forestall repeat commenters.