In a normal building site they either do very few cycles per hour (at heavy loads) or a decent number of cycles per hour at a tiny fraction of their load capacity.

Even when you use them intensively (with concrete buckets) to lift/pour concrete, that happens for a relatively short time (a few hours) each day.

A typical cycle is 5-10 minutes and you don't actually have 12 or 6 of them per hour, each hour in a normal 8 hour shift and - with some exceptions you normally have 1 shift per day, 5/7 (it is rare that a site working with cranes operates 24/7).

Besides, in a building site you don't work when it rains, and you cannot work with cranes if there is a not-so-strong wind blowing (for safety reasons).

[1] no reference, you will need to trust my word for it, coming from some 30+ years experience in building sites

I did notice that the cylinders were around twice the quoted capacities for tower cranes I was finding. It also sounds like they're building a much more expensive crane; that many cylinders, at 35 metric tons per and $90 for a yard of concrete, is upwards of $5m, and the article says that the concrete "could" be the most expensive part. Aaaaand random googling is giving me price tags for tower cranes that can't possibly be right - <$300k?! So the quoted system might be using a crane that's ten times the cost of a "normal" tower crane? I can... sort of seeing that buy a six-armed crane with twice the lift capacity but permanent construction, no need for a counterweight assembly, and better continuous performance. But now I feel like these numbers are lining up too well and I have to have done something wrong.

1. https://cms.qz.com/wp-content/uploads/2018/08/energy-vault-l...

2. http://www.wolframalpha.com/input/?i=3000+*+($90+%2F+cubic+y...)

A "normal" (very large) tower crane rarely exceeds 12 tons, BUT, more than that, usually these use not "single" cable, i.e. a largish crane is usually 6 tons max, but can lift up to 12 tons doubling the cable/rope (which implies halving the lifting speed).

Moreover, cranes are rated/designed (loosely) on their reach, they are intended - within limits - to cover a whole building site, so arms of 20-30-40-50-60 meters.

An electric tower crane (a "normal" one) is well below US$ 300 K, I seem to remember we paid for a very large one, 80/100 meters tall, 50/60 meters arm, 6/12 tons at arm point around 250,000 Euro a few years ago (but costs have not increased much as it is a stale market AFAIK).

The "key factor" is the "overturning" moment at the base (that implies a much sturdier tower and heavier coounterweights), and the single tower design is aimed to have a "light", "transportable" and "easily assemblable/disassemblable unit" the actual lattice is subject to very heavy tensile cycles as it is extremely flexible.

It would make much more sense (to me at least) to have a specially designed crane with an as short as possible arm, traveling on a track (which is also a setup commonly used in building sites) or a portal crane, like the ones used in quarries or pre-fabrication sites 35 tons are a lot of weight.

Besides (reinforced) concrete is at the most 2.3 tons per cubic meter, so it is not very efficient as a weight/counterweight, though possibly it is among the lower cost per kg material.

On the other hand rebar concrete is an excellent material for the actual tower, so in a fixed place it makes much more sense to build a (say) 100 m tall pier/pylon than using a "light" lattice /truss structure for the tower.

If you build a permanent crane for 30 year operation for most weather conditions it can be heavier and made of larger and heavier body segments. More like cranes in harbors.

I think the counterweights can be removed if you have symmetric working arms lifting exactly the same weight at the same time.

If a tower crane did not need to be transported, how much would the design change? I’m guessing not much, but curious.

I was imagining there would be no counterweight but just opposing loads, then I realized that might be a safety hazard. But, I really don’t know about these things.

I just love the elegance of this solution and immediately obsessed. I think it just ruined my productivity for the day.

1) be easily transportable, which among other things means that the lighter it is the better it is AND that in most countries the girdles cannot exceed 2.40 meters in width

2) most would be self-erecting (there are two kinds of self erecting cranes, the one in [1] is a kind limeted to smaller/shorter/less load models and it is properly "self-erecting") but any tower crane is normally assembled on the ground (using a crane truck) up to a given size/height, usually up to 30-40 m height at the most, for taller cranes, the arm and the base is assembled on the ground, but later the crane is assembled using a self-erecting "cage" or "climber" see [2], this again calls for "the lighter, the better", and implies besides the truss design the use of high tensile strength steel (which as said before is very elastic, meaning that the operation of the cranes is not as easy as you may think, particularly when high loads are involved, it is not uncommon that the point of the arm has several cms oscillation when the load is lifted/released)

3)transport/assembly/erection/disassembly is done relatively often it is rare that a tower crane remains in the same place more than a few months, at the most a couple of years, so the points above are very relevant.

A "static" crane would resemble more than anything else a port crane, more or less like this one:

https://commons.wikimedia.org/wiki/File:Port_crane_of_Mammoe...

[1] video of a self erecting crane:

https://www.youtube.com/watch?v=pqSFxZV6OvY

[2] video/animation of a climber crane assembly:

https://www.youtube.com/watch?v=RB91Sm-kGJ8

You can get around that, and they probably have to anyway, by just having a perimeter around the system that must be cleared by humans before the system can go active.

The use of space to store energy is maybe double of what typical damn reservoir uses to store the same amount of energy.

Here's some totally useless back-of-the-envelope calculations on land requirements for this sytem.

The United States, in total, used 1,819,393,805 MWh of energy in 2016. If one plant provides 35MWh of storage, that means 51,982,680 plants are required.

That comes to 84,211,942 acres of land. There are 2.3 billion acres of land in the United States, so it would require 3.66% of the US. That's obviously a huge overestimate.

The beauty of this is the simplicity. This is something we could have built 40 years ago. And unlike LIBs, there's much less worry about degradation and we can put these out in the desert near a solar power source without worry.

Imagine it combined with solar thermal, which has dropped immensely in price per KWh.

Also, concrete reabsorbs around 43% of the co2 used to create it over a period of time.

https://www.nature.com/articles/ngeo2840.epdf

10% of that makes more sense, even if it goes, let's say, 50% solar

As others have said,they likely would be placed near the solar plant where land is cheap and dry, rather than in neighborhoods.

10% would be overkill. I don’t think we should be aiming to sacrifice our livelihoods to be concrete block stacking addicted energy horarders, but I’m not entirely against that either. It’s hard to look at a solution so tangible and transparent as concrete block stacking before ducking my head into this mangled half-commented test suite.

But they'd probably be mechanized before long.

> If anything, that's a plus.

That's the world you want to live in, where there are more construction crane maintenance workers than teachers, police officer, food service workers, lawyers and doctors combined and then tripled? Is there no possible better use for human potential that fixing machines that lift bricks?

That's why I asked if that was the pinnacle of human achievement. If nothing was better. Because it crowds our other things at that level.

"Truck Driver", however, is a common job title[0] which may go away thanks to automation. Finding a replacement role would be nice.

I'm not sure you mean to insult people whose job it is to fix machines that lift bricks, by the way?

[0] https://www.npr.org/sections/money/2015/02/05/382664837/map-...

Why is working on power storage and generation meaningless? Cheap energy is literally the basis of our civilization, tech, and standard of living. Would you consider power plant work or oil drilling work meaningless?

Concrete has the advantage of lasting "forever" in those conditions (rebar when wet ruins it, otherwise it last long, long time). Concrete also stacks perfectly as you can mold it however you want. Might bite the bullet and stick with concrete, just work on making it more efficient.

http://documents.worldbank.org/curated/en/739881515751628436...

And methane is a greenhouse gas 20-80x more potent than carbon dioxide.

I'm sceptical of that. As the sibling comment noted, the technology is well-tested, yes but for a completely different usage pattern. You don't know how reliably construction cranes are in lifting heavy loads in back-to-back cycles, 24/7.

Additionally, I'd guess you will have to modify the cranes to realize the "recover energy" parts. I'm no expert, but I could imagine, traditional parts spend energy for both raising and lowering a weight because the design goal is reliable control of the load, not making energy. So you'd probably have to modify the motor assembly.

From what I've been told, the magic isn't in the generators (almost every project I'm working on is just using a standard industrial motor as a generator) but in the smart regenerative drives which both supply and harvest power from them. Harvesting power from industrial processes to keep costs down seems like it's a very common thing to do, so these drives are available off the shelf, and are designed to plug into a variety of existing motors.

That's definitely a really awkward choice of word in that context for it not to be intended, so I'm thinking pun was, in fact, intended. You can try to convince me otherwise but in order to do so I'll need to see some concrete evidence (pun not intended)

Anyway, I really didn't intend the pun! My reaction to the article was to try to get a rough estimate of how reliable tower cranes are, at which point I realized that they must be very reliable to work at all. But I only had that broad hypothesis of "very reliable", so I went looking for evidence to confirm it, and if so, what that broad hypothesis ended up looking like in practice. For whatever reason I found "concretely" when I went looking for a word for the segue. Probably concrete on the brain and a bit of luck.