No, Heavy Fluid Pumped Hydro Is not Remotely Moderately Or Economically Viable – CleanTechnica – Uplaza

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A current 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 concept, as all gravity storage choices that aren’t pushing water uphill transform.

As a reminder, gravity storage could be very primary stuff. The maths is Grade 5. The science is Grade 7. Mass occasions the acceleration as a consequence of gravity occasions top. Kilograms occasions 9.8 meters per second squared occasions top in meters. Joules are the unit of vitality this produces, and 1,000,000 of them is about 0.28 kWh. Sure, Joules are tiny. A ton of mass at 100 meters of top has about that a lot potential vitality, so should you have been to droop it with a crane with an electrical regenerating winch, you’ll 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, until they have been venally promoting it to STEM-illiterate fans with open wallets.

What’s heavy fluid pumped hydro? Properly, 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 prime, a reservoir on the backside, a tunnel or some actually robust pipes, and a few reversible hydroelectric generators. Pump plenty of filth low-cost water as much as a very easy higher reservoir via a tunnel via rock with actually easy electrical generators. Whenever you want electrical energy, let the water stream again down via the tunnel and generators to generate electrical energy.

Hills have been round for the reason that 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 carry recent water for the town’s 20- or 30-thousand residents. The primary hydroelectric turbine was in all probability inbuilt 1882 in Wisconsin, USA, of all locations. This isn’t remotely difficult know-how.

But some individuals suppose it actually wants enhancing on. A type of teams are the heavy fluids of us. Their considerations are some mixture of a scarcity of vertical distance, a scarcity of water, or a scarcity of locations to place pumped hydro. Let’s begin with the final one.

See all of these dots? A number of years in the past the Australian Nationwide College and a bunch of individuals led by researcher Matt Shares did a geographical data system examine. They’d a pc search for all of the locations on Earth for which there was first rate knowledge the place it was potential 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 top factor within the primary science). They eradicated anyplace there was operating water, to keep away from messing up streams or rivers. They averted locations that have been protected areas, largely parks and the like. They picked locations that have been pretty near current transmission traces, so it will be simple to carry electrical energy to and from the reservoirs.

They discovered a reasonably 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 individuals reside, and there’s no transmission and even good knowledge units. They discovered 100 occasions the useful resource potential for pumped hydro as the entire quantity of vitality 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 web sites to place closed loop, off-river, pumped hydro electrical energy storage. That’s two of the objections knocked off the listing, locations to place it the place there may be adequate top. Oh, wait, say the pumped hydro critics. What concerning 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 individuals have by no means heard that we are able to transmit electrical energy, or that there’s this factor referred to 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 massive grid storage one. Its top distinction is 500 meters. Its round-trip effectivity is about 80%. It might require round 28 million cubic meters of water. That seems like quite a bit.

How a lot recent water does the USA eat each day? About 1,200 million cubic meters. Do pumped hydro amenities eat 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 each day, they only play with the water they’ve. 30 GWh of storage requires about one-fortieth of a single day’s water consumption, and doesn’t eat it. That’s about one sixteen-hundredth of the USA’s annual water consumption. When pumped hydro amenities are constructed, generally the builders simply allow them to refill with rain water, though that’s pretty sluggish. Many are actually replenished with rain sufficiently to require that extra water be fed into close by streams or rivers. Others run pipes or construct non permanent channels from close by rivers or lakes.

If you’d like extra vitality storage, simply make the highest and backside reservoirs larger. Larger reservoirs are remarkably simple to construct. They’re the least tough 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 have got 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 amount 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 edges of the dice to 80 meters and the amount 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 tough, in different phrases, to determine what drawback the heavy fluid of us suppose that they’re fixing. Are they making it cheaper? Are they making it extra handy to seek out fluids? Are they rising the variety of websites with 400 meters of head top or extra? Properly, no.

What are they claiming? That by utilizing heavier fluids, they will scale back top or quantity of fluids, usually by 60%. Bear in mind, it’s mass occasions acceleration as a consequence of gravity occasions top. There aren’t any exponents in there, not like with the amount of reservoirs cubing or wind vitality swept space squaring or wind velocity energy cubing. The rise of vitality for pumped hydro by making the fluid heavier is linear. Double the mass of the fluid and also you get double the potential vitality storage.

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

How are they doing that? One proposed methodology entails 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 as a consequence of their increased densities and secure properties. However nobody is making an attempt to commercialize any of the above.

There’s one agency on the market which is making an attempt to commercialize a special answer, fine-milled solids in a suspension in water. What does that imply? A suspension is a bunch of strong particles floating in a liquid. Depart them alone they usually’ll sink to the underside or float to the highest ultimately. How dense the ensuing heavy fluid is decided by the combination density system, which is fairly primary. These aren’t options, that are like a full jar of marbles that you just add water to with out enhance the amount of the jar. The strong particles displace water.

They’re asserting that their fluid has 2.5 occasions extra mass per cubic meter as water. In consequence, they will use 40% of the water or 40% of the peak and get the identical vitality storage. Provided that neither water or top are remotely restricted assets or significantly exhausting 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 quicker. Larger, lighter particles rise to the floor quicker. Therefore, fine-milled solids, on the size of micrometers or nanometers. There are 1,000,000 micrometers and 1,000,000,000 nanometers in a meter. They’re tiny particles. You is perhaps pondering to your self, how will we make particles of stuff that small, and the way a lot does it price? Good query.

Ball milling is a extensively used methodology, the place supplies are floor in a rotating cylindrical chamber with metal or ceramic balls, reaching particle sizes within the micrometer vary via repeated affect 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 — supreme for heat-sensitive supplies. Attrition milling entails grinding materials by friction and shear forces in a mill with rotating discs or arms, producing high quality and uniform particles for numerous industrial purposes.

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 strong 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 lively substances. The commonest of those is microcrystalline cellulose constructed from wooden pulp, however its density is far decrease than water.

My first thought was that the key sauce is perhaps silicon dioxide, often known as colloidal silicon, generally used as a bulking agent in tablets. The colloidal half is necessary for this. Colloidal suspensions are totally different than non-colloidal ones in just a few methods, however the vital one is that the particles don’t settle out, being high quality sufficient to remain within the combination via 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 drawback. 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 while you add the densities collectively it doesn’t come near 2.5 occasions the mass of water.

This implies that they aren’t utilizing silicon dioxide, or if they’re, they’re getting the tip mass improper. Not getting the fundamentals of physics proper is comparatively widespread for individuals who attempt to outdo primary 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, they usually or the individuals 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 combination of 5% bentonite and 41% barite in water would have a density about 2.5 occasions that of water, and it will be a colloidal suspension. It’s completely potential to realize the two.5 occasions mass for a similar quantity that the corporate claims, in different phrases.

What would this price? What does water pumped from a lake or river price? Allow and utilization prices is perhaps 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.

Tremendous milled barite usually 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. Choosing the averages, that means that 5% bentonite and 41% barite would price about $87 per ton of substances, 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 vitality storage.

What would this do to the capital prices for a reasonably-sized pumped hydro answer, that’s, one which was price constructing? Let’s take the 30 GWh answer above. The large declare of the agency in query is about top, 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 fundamental pumped hydro facility would price $3 to $9 billion to construct, a median of $6 billion. Filling it will price one other $112 million, a fraction of the development price.

Constructing a 200-meter top facility with the identical dimension tunnels and reservoirs saves a little bit of building prices, however not that a lot. Name it $2 to $7 billion for a median 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 price $2.5 billion. A lot for that saving. Add a billion to the capital prices.

Really a bit extra. The bentonite and barite aren’t going to get to the positioning at no cost. Let’s assume that they need to 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 fee. It’s now $1.7 billion extra, about 33% costlier, for a similar vitality 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 vitality storage.

However let’s get again to that viscosity. How rather 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 stream fee, with the stream fee inversely proportional to viscosity as described by the Hagen-Poiseuille equation. For example, a fluid with 100 occasions the viscosity of water would stream at only one% of the speed underneath similar strain and diameter circumstances. 50 cP could be 2% of the speed. 200 cP could be 0.5% of the stream fee.

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

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

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

Positive, massively scale up the tunnels or pipes, generators, and pumps. The identical equation that advised us the fluid stream can be utilized to determine how a lot larger they must be, and at 100 cP, they’d should be 3.16 occasions larger. 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 leads to higher 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 initiatives. The hypothetical $4.5 billion dense fluid pumped hydro answer 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 grow to be $12 billion to $14 billion extra. The $6.1 billion primary water pumped hydro answer is now a 3rd the price of the dense fluid answer.

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, quite a bit. A 50 cP fluid has 50 occasions the friction as a result of Reynolds quantity within the Darcy-Weisbach equation for head loss, so 50% to doubtlessly 150%, one thing that couldn’t even get via the turbine as a consequence of friction, simply ooze gently via 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 median 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 vitality than if it have been water. It flows 18 occasions extra slowly with the identical strain and diameter of pipe or tunnel. That will 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 quite a lot of friction. In an ideal world, shampoo, after slicing recoverably potential vitality 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 all the electrical energy put into the system misplaced to inefficiencies.

What a couple of tiny system, possibly 10 MW / 100 MWh, utilizing pipes as an alternative of tunnels? Properly, the entire capital price could be excessive, however is perhaps within the vary of batteries. However the round-trip effectivity would kill it. A bentonite-barite suspension, which may get to the density necessities, fails in two separate methods to realize its ends.

Not one of the above is remotely tough to observe for individuals with primary 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. Properly, the cross-section and quantity of cylinders is. Viscosity calculations have to attend till Grade 11 or 12, though the fact that extra viscous fluids stream extra slowly is launched years earlier. Civil engineers get the Darcy-Weisbach equation in first 12 months of faculty or college, however it’s completely potential that some excessive faculties introduce it in superior placement course in Grade 12. It’s not exhausting, simply not instantly helpful.

The one one which’s remotely superior is tunnel diameter considerations associated to compression and collapse, which is launched usually 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.

Properly, let’s return to the silicon dioxide 60% answer. 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 as a result of elevated particle focus. 30 cP, in fact, means it will ship 30 occasions much less vitality for a similar mass and see 30% effectivity losses in each instructions. 60% extra potential vitality would flip into vastly much less actual vitality.

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

Is there any means round this? Positive, 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 very best case. A bentonite-barite answer 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 vitality per cubic meter drops as effectively.

And to be clear, because of this they need to get warmth from someplace. Their patent makes it clear that they’ve figured this out, at the very least partly, as a result of pages are dedicated to getting warmth from geothermal or fuel generators in addition to having warmth exchangers and warmth pumps everywhere.

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

Lowering viscosity with warmth trades one vitality drawback for one more. That’s thermodynamics for you, an actual buzz-killer at vitality business cocktail events.

Is it potential that the agency in query has created a non-viscous colloidal answer with another fine-milled strong and a few components? Deeply unlikely. Viscosity of a fluid with fine-milled particles is a operate largely of the particles, which have bodily mass. The truth is, the finer the particles, the higher the viscosity, and the particles should be actually high quality as a way to be in a colloidal suspension. The properties of liquids are a really effectively mined discipline. There are high-density, low-viscosity fluids, however they’re issues like chloroform, mercury, and bromine. None of these are remotely smart to make use of as a consequence 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’d be promoting it to the drilling business and probably choosing up a Nobel Prize.

Whereas I had enjoyable operating the numbers and determining what supplies in what combos they have been prone to be utilizing, this isn’t just like the gravity vitality storage system that fracks the identical quantity of shale again 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 turned apparent, largely 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 manifestly apparent. Quantifying them and determining the sting circumstances took time, however not realizing that the answer wasn’t viable. And simply as with the fracking answer, 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 data.

Bear in mind, the fundamentals of viscous fluids shifting slowly are grade faculty stuff, whereas the calculations are Grade 11 or 12. All people 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 quite a bit tougher than stirring water. Tunnels three and a bit occasions wider being ten occasions the amount 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 companies 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 traders which have apparently given them just a few million ask any of this? Why didn’t any of the funding organizations ask individuals who would be capable 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 take a look at their slowly pouring shampoo and have a weak little lightbulb go on about what it implied about dense fluids and vitality storage?

Like utilizing cranes to raise concrete blocks as an vitality storage answer, 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 will sink and not using a hint. Sadly, no. Somebody all the time feedback on its wonders after I discuss pumped hydro’s world progress fee or the failures of different forms of gravity vitality storage. At the very least now I’ll have an evaluation to answer with, reasonably than just a few scathing phrases about oozing sludge not being remotely an answer. Maybe it can stop repeat commenters.