Gravity Storage 101 Or Why Pumped Hydro Is The Solely Remotely Actual Gravity Storage

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In my latest article celebrating the good month that pumped hydro had, between the Loch Ness Purple John facility promoting to Statkraft, the UK lastly selecting cap and ground for the know-how and China having 365 GW of energy and 4 to eight TWh of vitality storage beneath development, I included a throw away line.

As a reminder, pumped hydro is the gravity storage answer that really works, in contrast to concrete blocks, elevators and hillside rail methods.

This triggered the entire individuals who assume Power Vault has a remotely wise know-how and the tiniest probability of delivering something of worth, the individuals who just like the ARES rail-based gravity storage nonsense and doubtless those who assume unused workplace elevators, water towers, and mines and massive piles of sand are an enormous supply of untapped storage as effectively.

So it’s time, as soon as once more, for the fundamentals and a bunch of examples so that folks can cease fantasizing about elevator, cranes or trains and concentrate on water and present hills as an alternative.

Let’s begin with the fundamentals of the physics. Gravity storage works due to potential vitality. That’s merely a mass greater up. Because it goes down, the potential vitality turns into kinetic vitality, the vitality of motion. Because it goes down, we will harvest that vitality. It takes vitality to maneuver the mass upward, and may get various levels of vitality again from it on its method down.

That is all topic to the legal guidelines of thermodynamics. Let’s use British writer and scientist C.P. Snow’s model:

• You possibly can’t win (that’s, you can’t get one thing for nothing, as a result of matter and vitality are conserved).
• You possibly can’t break even (you can’t return to the identical vitality state, as a result of there’s 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).

What which means is that if you happen to put 100 MWh into an vitality storage system of any variety, you’re going to get lower than 100 MWh again. That’s often necessary, however not with vitality storage methods that aren’t pumped hydro utilizing present hills. There’s no method across the three legal guidelines, there’s no reinterpretation of them that allows them to be sidestepped (as one remark I noticed not too long ago mentioned for his or her know-how) and everybody has to play by the identical guidelines.

Okay, so it’s vitality and we’re going to get much less out than in. How will we work out how a lot vitality? That’s straightforward. Multiplying the mass occasions the drive of gravity occasions the peak will get the potential vitality, the utmost quantity you will get again. That’s in joules, which isn’t useful for the typical one that by no means makes use of joules, however one million joules is 0.277778 kWh. The opposite method round, a kWh has 3.6 million joules.

As a result of that is metric, we use meters, kilograms and gravity is measured in meters per second squared, 9.8 of them to be considerably exact. Let’s begin with a hypothetical state of affairs, a one metric ton or thousand kilogram block we transfer up 100 meters. Good spherical, easy numbers.

1,000 kg * 9.8 m/s^2 * 100 m = 980,000 joules. That looks as if an enormous quantity, however that’s solely about one million joules which suggests it’s equal to about 0.277778 kWh.

A Tesla wants about 14.4 kWh to journey 100 kilometers, so this one ton block transfer up 100 meters is sufficient to drive a Tesla just below two kilometers. One other method to think about it’s that it is sufficient to boil a pot of water.

For these unfamiliar with metric, that’s near the size of an American soccer discipline however straight up and a couple of,200 kilos. To boil a pot of water. Electrical vehicles are actually environment friendly.

Okay now that now we have the fundamentals, let’s take a few examples. Let’s begin with the ARES rail system. I haven’t bothered to have a look at them carefully as a result of they’re clearly nonsense and nobody has aggravated me about them an excessive amount of, however I’m pretty acquainted with heavy freight rail and know that ARES has to play by the foundations identical to everybody else.

Metal wheels on metal rails signifies that heavy trains require lower than 2% grades in any other case they will’t go up hills. Meaning you want a really lengthy set of rails to get very a lot top. The size of the practice signifies that it could’t get all of it up or down the hill, so you’re working with a portion of the slope.

Let’s load the rail vehicles as much as the utmost 130 metric tons for heavy freight rail every. Let’s use comparatively customary 18 meter vehicles. Let’s use 50 vehicles for an honest size and mass practice. That makes it 900 meters, nearly a kilometer lengthy.

At 2% grade, you’d want 10 kilometer of monitor to get 200 meters of head top. However the trains size truly means you’d be solely getting about 9 kilometers of rise of the middle of gravity, so it’s truly 180 meters.

50 vehicles * 130 metric tons is 6,500 metric tons complete mass.

Mass * gravity * top = 6,500,000 kg * 9.8 m/s^2 * 180 meters = 11,466,000,000 joules. That’s about 3.2 MWh.

The present Tesla Megapack is customary transport container dimension top and width, 29 toes lengthy and shops 3.9 MWh. You possibly can put them within the nook of parking tons.

Yeah, an nearly kilometer lengthy practice with ten kilometers of monitor has so much much less vitality storage than a transport container filled with Tesla’s batteries.

There are funicular railroads that go up steeper pitches, however they’ve vastly much less mass as a result of the pressure on the cables will get so excessive that they snap. Shorter distances up steeper slopes contain related heights however vastly much less mass, so vitality storage drops by one or two orders of magnitude.

I don’t know what ARES is definitely claiming it’s doing as a result of it’s not value studying its web site, however it’s actually this stupidly unhealthy.

That is bleedingly apparent to anybody who has spent any time doing mass and vitality calculations, one thing taught in Grade 7, which is why individuals like me assume that issues like Power Vault will fail and disappear with out a hint, forgetting the gullibility of enterprise capitalists, the venality of SPAC pump and dumpers and the credulity of retail buyers. Fools and their cash are quickly parted. Hopefully this may inoculate a number of individuals.

Since we’re speaking about Power Vault, let me repeat my calculations from a couple of articles I wrote when the aforementioned gullibility, venality and credulity truly meant it had a market capitalization and getting numerous press.

Their first design, which they managed, remarkably, to make worse, had the crane within the middle and a bunch of concrete blocks that it could choose up and stack on high of one another. The concrete blocks had been alleged to be 32 metric tons and the utmost stack dimension was 120 meters.

32,000 kilograms * 9.8 m/s^2 * 120 = about 37 million joules or about 10 kWh. That’s for one block going up the utmost distance.

However bear in mind, they had been stacking them. The typical block was solely going up half the gap, so each block was solely about 5 kWh of vitality. With 100 blocks, a notional and certain most quantity doable in a round system like that, that’s solely half a megawatt hour (MWh) of electrical energy storage in the very best case state of affairs.

The typical residence makes use of twice that a lot electrical energy yearly. It’s solely sufficient to cost 5 lengthy vary Teslas, and isn’t sufficient to cost a Tesla Semi.

So lengthy earlier than you get to the effectivity downside — pretty poor — and the operational challenges like wind and cracked blocks, Power Vault is extra like Power Paper Cup.

Their second design solved for the wind downside by making the whole factor shorter and into an enormous, 25 story, 75 meter heavy metal framed constructing with completely large winches on high, with barely smaller 27 ton blocks on rolling carts.

They’re stacking blocks on the underside so lose some top from that. They will’t get all of the blocks to the highest of the constructing. 50 meters might be an inexpensive common per block.

27,000 kilograms * 9.8 m/s^2 * 50 = about 3.7 kWh per block.

Let’s suppose they managed to get 5 hundred of those large blocks working within the system. Unlikely, however let’s fake. That’s only one.85 MWh of storage, about half what’s in a single Tesla Megapack. In a 25 story excessive, thick metal framed constructing with mining grade winches on the roof.

They declare, after all 40 MWh of storage, which might require lifting about 11,000 of their blocks to the highest of the constructing, the place there’s completely not sufficient room for them. There isn’t room for that many blocks in the whole inside quantity of the constructing almost definitely.

Hmmm, I haven’t executed that calculation. How a lot house would 10,800 blocks weighing 27 tons every of bolstered concrete take up? It’s 2.5 tons for a block a meter on a facet. Meaning the 27 ton blocks can be three meters on a facet, which for the People studying alongside, just below 10 toes on a facet. You’d want a few meter between blocks at minimal for tools, carts and people large help metal girders, so let’s lengthen that out by half a meter in all instructions, making the house requirement 4 meters on a facet, or 13 toes.

Let’s make an enormous sq. of 10,800 blocks. How extensive is that? The dice root of 10,800 is round 22. That makes a sq. stack of those blocks with a little bit of room between them 88 meters excessive, 88 meters extensive and 88 meters lengthy. Does anybody discover something flawed with this? Maybe that 88 meters is 13 extra meters than the Power Vault constructing is tall, and with zero room for the blocks to maneuver anyplace? Take away the spacing between them, and simply the blocks that may retailer the vitality that they’re claiming is nearly as huge as the whole constructing. But somebody they will match all that into the highest couple of flooring? Magic house compression anybody?

As soon as once more, everyone seems to be compelled to play the identical sport as a result of that’s the legislation of thermodynamics and the sheriff is actuality. Power Vault’s storage claims are full and utter fabrications which fail absurdly easy physics checks. Let’s ask a query. When is these things taught in merely satisfactory colleges. Reply? Grade 7.

That is actually a check a Grade 7 scholar might discover on a check, but individuals put some huge cash into it.

Oh, and even with their absurd effectivity, lifespan and uptime claims, all that concrete and metal would have meant each MWh for 40 years would have had a carbon debt larger than burning pure fuel.

There’s a motive why as soon as the mud settled after the pump and dump SPAC, Power Vault employed a lithium ion battery web site developer and began promoting nearly solely lithium ion batteries in transport containers as grid storage to purchasers. That some Chinese language persons are apparently additionally gullible and credulous and have truly purchased and are establishing a few of these issues doesn’t imply that it’s a remotely helpful vitality storage gadget. That what funding cash was left over after the SPAC Wall Road individuals took their large lower is usually going into the pockets of the 2 … eermmm … “inventors” of this nonsense goes with out saying. After making an attempt for 20 years to promote this sort of nonsense to credulous idiots, they lastly succeeded.

Okay, that’s sufficient kicking Power Vault — though actually, I don’t assume that they’ve been kicked almost sufficient, it’s simply that I’m uninterested in doing it proper now. Let’s discuss water towers.

By now, you understand what the questions are. How tall is the middle of gravity of the mass? How a lot mass is there? Be happy to make use of that extremely troublesome scientific instrument, Google, that can assist you reply these questions.

Nah, I’ll simply do it. They vary from 40 to 50 meters. When you’ve learn this far, your spidey sense shall be tingling already. That’s simply not that a lot. What about mass? On common, about 3,800 metric tons of water. Properly, your spidey tense have to be ringing alarm bells proper now. However nonetheless, let’s do the mathematics. Let’s give it a break and assume a 50 meter water tower.

However that mass isn’t all 50 meters off the bottom. Water has a thousand kilograms per cubic meter, which is an instance of why the rational elements of the world use metric. Meaning 3,800 cubic meters in a ball. How huge on a facet is that with the shell? About 16 or 17 meters in diameter. My guess earlier than calculating was 15 meters, which is 0.6 meters off the diameter if the ball of water was simply floating in house. Not a nasty guesstimate, and par for the course for anybody who spends any affordable period of time with this sort of factor. My being shut isn’t a function or one thing particular in different phrases, it’s simply an occupational hazard.

Okay, so the middle of gravity of the water is just 37.5 meters off of the bottom. Massive crimson lights and sirens needs to be going off now.

3,800,000 kilograms * 9.8 m/s^2 * 37.5 = round 390 kWh. That’s possibly half a Tesla Semi battery again and a tenth of a Tesla Megapack.

However wait, there’s extra. Why do water towers exist? To offer water strain to communities in order that water truly comes out of faucets and hearth hydrants when wanted in adequate volumes. What’s water strain? Power. Oh, wait. If we take the entire vitality out of the water because it comes out of the water tower, which means there’s no vitality left for water strain. Dribbling showers and hearth hoses aren’t any enjoyable in any respect.

What haven’t I ripped to shreds with Grade 7 physics but? Oh, yeah, mines and sand. I actually want individuals weren’t critical about this, however they’re.

There are a few concepts, however the looniest one is sinking sand into an empty mine in huge buckets with regenerating winches, dumping the sand out on the backside and having huge automobiles push the sand down facet tunnels. To ‘retailer’ vitality, the automobiles working underground would scoop up the sand and dump it again into the buckets which might be raised to the floor.

Cease and take into consideration that for a minute. Utilizing plenty of vitality underground to push sand round when the purpose is to retailer vitality. Why is that being executed? Properly, sand isn’t a liquid, it’s only a bit liquidy a number of the time. Sand flows, however not like water. Pour water right into a mine and it’ll fill each nook and crevice as a result of it’s molecules of dihydrogen monoxide.

Water molecules are 0.275 nanometers. Sand grains common a millimeter. Nanometer, millimeter, what’s six orders of magnitude amongst associates? Water molecules are about 4 million occasions smaller than sand, and so they aren’t all lumpy, coarse and spiky. They slip previous each other higher than the best high-thread rely Egyptian cotton or silk sheets it’s doable so that you can think about.

So that is clearly a deeply silly concept, and but I’ve seen individuals who significantly proposed it. The inefficiency is off the charts, and simply think about even autonomous electrical entrance finish loaders driving always by way of a mud cloud of smaller sand particles, getting of their gears.

The choice concept is to place plenty of sand on a single elevator with big winches that simply goes up and down in an enormous, deep mine shaft. This one at the very least has the potential to be viable. Let’s fake we will discover a kilometer deep mine shaft that’s deserted and hasn’t stuffed with water as much as the 30 meters under floor stage mark. Oh, wait, we will’t discover one thing like that as a result of floor water? Ignore actuality for a minute.

Mine shafts have a diameter of 5 to twenty meters. Let’s fake now we have an enormous 20 meter mine shaft that’s a kilometer deep and never filled with water. Okay, how huge a load of sand can we placed on an elevator in a 20 meter diameter shaft? Let’s assume we will put it in an enormous bin ten meters tall. In order that’s 20 meters in diameters and 10 meters tall of sand. That’s so much. For People, that’s 66 toes throughout and 33 toes tall.

The quantity of a cylinder that dimension is 3,142 cubic meters. By the best way, calculating that’s taught in eighth Grade. We’ve superior all the best way to 13 12 months previous kids in fundamental colleges in our math and physics.

Sand has a density of about 1,600 kilograms per cubic meter. That’s about 5,000 tons of sand. Hmmm. Do now we have winches that may raise 5,000 tons? Errr. No. That’s nearly precisely ten occasions larger than large winches for deepwater development. Okay, let’s pare that again. Perhaps a 1,000 tons of sand? Lower the depth to 2 meters as an alternative? Positive. Let’s do this math, as soon as once more, for this fictional, big, water free, deep mine shaft, one in every of which could exist on this planet.

1,000,000 kilograms * 9.8 m/s^2 * 1000 meters = about 1,360 kWh. That’s 1.4 MWh.

That isn’t very spectacular. A kilometer deep shaft with an enormous elevator filled with two meters of sand labored by a few the most important winches ever constructed and it’s solely as a lot as a 3rd of a Tesla Megapack that’s 29 toes lengthy and eight.5 toes tall.

By the best way, sand is dust low cost and the physics of winches signifies that it actually doesn’t matter if you happen to make the load denser, for instance by utilizing lead. Doubling the load nonetheless solely will get to 2.8 MWh, which is an terrible lot of engineering and development for a return effectively under one thing you’ll be able to order and have dropped within the nook of a car parking zone.

Are we executed but? Not an opportunity. There are a bunch of people that assume that workplace constructing elevators are an untapped useful resource of vitality storage.

They assume that at evening, huge dollies of heavy stuff may be shoved into freight elevators within the basement, lifted as much as the seventy fifth ground, and rolled into govt places of work and board rooms, then within the morning, dropped down once more to generate electrical energy.

I actually want individuals weren’t saying this significantly. I actually, actually do.

Okay, let’s make consider for a bit. How a lot weight can workplace constructing freight elevators raise? Massive ones can handle 9 tons. What’s that sound? The sirens of spidey sense whooping. What’s that noise? The multicolored lights of spidey sense flashing. 9 tons? We’ve been speaking about hundreds of tons. 9 of them? Actually?

Okay, however 75 tales. That’s so much, proper? That’s like, actually excessive? Positive. Perhaps 225 meters. Okay, Grade 7 math time once more.

9,000 kilograms * 9.8 m/s^2 * 225 meters = about 5.5 kWh.

Some sweaty lackey goes to load 9 tons of paper or sand or stale birthday cake onto an enormous dolly, grunt it right into a freight elevator, then grunt it into board room, then reverse this course of the subsequent day, and that is an vitality storage answer?

Let’s simply throw an enormous bucket of ice water onto this already absurd nonsense. Have you ever heard of counter weights? Elevators have these large weights that go up when elevators go down and vice versa to counteract all the load of the elevator, cable, friction and the workplace staff. The purpose of that’s effectivity in transferring weight up and down. All of these elevators don’t have even 5.5 kWh to spare as a result of they’ve been designed to keep away from needing it.

The individuals who assume this concept is sweet have zero data of vitality, Grade 7 math or absolutely the fundamentals of elevators. Maybe they had been residence schooled within the prairies by Luddites or one thing. Decide your motive why this utterly absurd concept was truly gaining traction.

So let’s discuss closed loop, off-river, pumped hydro storage. Because the article headline says, it’s the one actual gravity storage possibility. Why? Properly, as a result of it has billions of kilograms of mass tons of of meters of distance between high and backside. Geography creates the peak free of charge, simply requiring a ten meter diameter tunnel be dug by way of it, which admittedly is dear and dangerous. And water’s tiny molecules don’t want any assist to arrange themselves. None of these sweaty pressured workplace staff. None of these large front-end loaders pushing sand down tunnels. Simply pumps.

The mass and top are each huge numbers. The mass particularly is a extremely huge quantity. And water is dust low cost. This isn’t filtered, bottled, purified, chlorinated water. It’s simply lake or river water. The water isn’t consumed. It goes up. It goes again down. It goes up once more. Advert nauseum. If water might get bored, it could. A few of it evaporates yearly, so the system must be topped up. Nothing burger.

Okay, let’s do some math. Let’s go to the Australia Nationwide College inexperienced discipline GIS research of potential paired reservoirs that weren’t on present water pathways, that had been near transmission, that weren’t on protected land and that had over 400 meters of distance between high and backside reservoir. It discovered 100 occasions the potential capability for vitality storage as the whole world requirement for vitality storage ultimately sport.

Only one% of the websites should work out in an effort to present all of the vitality storage for a completely electrified world powered by renewables. And some blockers have already been eradicated. Near transmission and never on protected land, bear in mind? Somebody complained to me not too long ago that precisely one in every of 616,000 websites recognized had 14,000 individuals that may be displaced. So go to the subsequent web site already.

Math although. Let’s choose a 500 meter head top web site. Let’s choose a billion liters of water, a gigaliter weighing a billion kilograms, one million tons. Wait, what’s not taking place? Your spidey sense isn’t flashing lights and blaring alarms. These are huge numbers on each side.

1,000,000,000 kilograms * 9.8 m/s^2 * 500 = 1.4 GWh of grid storage.

Oh. GWh. Vital grid storage. Okay, now we’re speaking!

Let’s take the three Clever Land Funding websites in Scotland, together with the Loch Ness Purple John web site that was not too long ago offered to Norway’s Statkraft. They’re designed to make use of lochs as their decrease reservoir and turkey’s nest reservoirs on overlooking hills as higher reservoirs. A number of water. A number of top. Free water as a result of it’s simply sitting there within the lochs, ready to be pumped uphill in a really low environmental influence method.

2.5 GW of energy capability. 60 GWh of vitality capability.

Tesla Megapacks can ship about 2 MW of energy. That is like 1,250 of them. They will retailer about 3.9 MWh of vitality. That is like 15,000 of them.

Properly, these have to be huge reservoirs, proper? No. A sq. kilometer up high, a sq. kilometer on the backside. Ponds.

Pumped hydro is the one actual gravity storage answer as a result of it makes use of a dust low cost, excessive mass, simply pumped mass and makes use of present geographical function to create huge top variations. Each different gravity storage answer is youngsters taking part in round in a sand field.

I’ll repeat this. Grade 7 math is all that’s required to determine this out. Entitled Hollywood belief fund youngsters Chad and Buffy, who get gold stars for attending class, are anticipated to have the ability to do that actually fundamental math in checks to cross and get to Grade 8, maybe with examples of caviar on facet tables falling on the ground. Anybody who thinks that something aside from pumped hydro is remotely wise is a number of of some issues. They’re silly. They by no means made it by way of Grade Seven. They’re deeply lazy. They’re credulous. They’re gullible.

Don’t be that individual. That is in regards to the lowest bar in vitality that it’s doable to seek out. When you can’t determine this out, you aren’t remotely competent to have discussions about any of the truly fascinating stuff in vitality, like Ohm’s Regulation or substituting aluminum for copper in HVDC cables or why baseload vitality is an archaic time period left over from tiny grids enshrined in regulation gone its promote by date.