The selling point of this is low relatively low capital cost and well tested technology. Power density is not that good, but if you have land that's not a problem.
The use of space to store energy is maybe double of what typical damn reservoir uses to store the same amount of energy.
Each 35MWh system requires about 1.62 acres of land. That seems perfectly reasonable to me, especially since there are still optimizations to explore.
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.
Yeah, storing (<1%) 3 days total annual supply of electricity would be a huge over estimate... and storing 10% (35 days)would still be crazy large... I'd think the grand parent posts's numbers are high by 2-3 orders of magnitude.
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.
In this hypothetical, you also need something like ten percent of Americans to be crane maintenance workers, wouldn't you? Based on the crane numbers above it might even be more.
>> ten percent of Americans to be crane maintenance workers
> 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?
Honest question: what's wrong with being a crane maintenance worker or a crane operator? Cranes are cool, cranes help build stuff, cranes are complex. And if anything, out of the list of "desirable" jobs you mentioned at least two (police officers and lawyers) are the result of "bugs" in our societal system, they aren't productive.
Nothing is wrong with being a crane maintenance worker, and there is nothing wrong with being an accountant. But if a fifth of the workforce was accountants I would enter a panic.
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.
Gov't (fed, state, muni) employ about 23 million workers. Total workforce is about 130 million. So gov't work is roughly 1/5 of the workforce... hehehe.
Better than 10% of the US being truck drivers. Maintenance on heavy equipment like that can be remarkably complex, and the necessary skills are transferable to all sorts of industrial and fabrication jobs - not too hard to switch from fixing the hydraulics and armatures on a tower crane to fixing the same on any other sort of crane, vehicle, or chunk of factory equipment.
If all they did was make a battery, that's messed up. That many people? That's so much less useful to society than teachers, food service workers, doctors, lawyers and etc. combined. The insult to those people would be to have them spend their lives doing something so meaningless. Operating a crane in a construction crew has maybe a thousand times more dignity because they are making something people want. I have truck driver friends and that job isn't the best but they're doing something people want, they don't get out of bed unless something is out of place in the world, and they fix it.
> The insult to those people would be to have them spend their lives doing something so meaningless
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?
The system described in the article is mainly automated. They probably wouldn't need a large team to manage the system or it would be completely unfeasible. Certainly no worse than a giant battery center used to store electricity.
Reservoirs are restricted in where they can be built, because water. And that real estate is in high demand for many other uses. I think it's a safe assumption that, in general, coastal properties (including those on lakes and rivers) are more than twice as valuable as inland property on average.
Reservoirs could probably be built underground. I could also see one of these block stackers existing in the sublevels of a big skyscraper. Cost and and difficulty of access for maintenance might make either thing impractical, though.
they could make steel cages, fill them with crushed and vibrated limestone (or another aggregate). Good steel for the cage would last a lifetime but not sure if it's cheaper in $$ or CO2 emissions. Basically they need to lift /drop a heavy thing that last generations and stacks well.
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.
Probably you could throw in a small amount of nanocellulose and it could improve the strength a lot. Especially tensile strength, which is not good for concrete.
Not a true expert on the topic but from my reading it sounds like land is generally a carbon sink and water produces carbon so when you turn land into water, the net effect is additional carbon. Estimates have man-made reservoirs accounting for 0.5% of the total anthropogenic carbon emissions worldwide; fairly significant when we're considering the scale needed for energy storage with wind (blows 35% of the time, US avg.) and solar (shines 25% of the time, US avg.).
It's carbon neutral when plants decay to carbon dioxide. But they need oxygen for this to happen - and when they don't (like when they're underwater), they decay to methane.
And methane is a greenhouse gas 20-80x more potent than carbon dioxide.
< The selling point of this is low relatively low capital cost and well tested technology.
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.
I've recently started working with wave and tidal energy projects.
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.
The use of space to store energy is maybe double of what typical damn reservoir uses to store the same amount of energy.