- Someone needs to watch the stacking process. If there is a single error the whole tower can collaps and do a lot of damage.
- You need a big (and expensive) foundation for a tower like this.
- Is the low-cost-concrete a strong enough building material?
- The generator needs cooling (in hydro pump it is cooled by the water flowing through)
Why do you say that? We have fully automated CNC machines and 3D printers that can make things to amazing tolerances without human intervention. Stacking blocks neatly isn't a hard AI problem like self-driving cars are.
> If there is a single error the whole tower can collaps and do a lot of damage.
My reading of it is that the whole thing is fenced off anyway, since it contains an autonomous crane. Just put it somewhere that land isn't too valuable. If it all does collapse, the worst that can happen is it damages itself. Most wind turbines are similarly situated in places where, if they fail, there's nothing else really there to damage anyway.
> Is the low-cost-concrete a strong enough building material?
Presumably so, or if it's not, then it won't be used. I'd leave that to the engineers.
> The generator needs cooling (in hydro pump it is cooled by the water flowing through)
Cooling is not a hard problem. There are much larger plants generating way more power that operate 24/7 that handle cooling just fine. This idea is only generating as much power as a tower crane typically uses anyway, so whatever a tower crane has for cooling its motors should be fine. Probably some kind of closed loop liquid cooling system going to a big radiator with fans, like for a typical automobile engine.
Those are very controlled environments. Outside where there is weather and wind, anything can happen. Also if there is a bug in the software or some hardware fails in a CNC machine then you loose some material, not a big of a deal. If the concrete tower collapses you loose a skyscraper volume full of concrete, also it takes days or weeks to clean the area up.
First, make them out of a shape that naturally fits together.
Then, build them with a vertical hole (shaft) through them. Put a reflector under the bottom one. Before the crane releases a block, it shines a light down the hole and checks if it is reflected back. Misalignment will block the light. (Or, you can do something similar with electricity, connected contacts on the top and bottom, and a check that current flows through the entire stack.)
In that case, something comes along and cleans it. Maybe a rod-shaped brush (like a vacuum beater) that spins. Or a water jet.
Also, you can have more than one hole for redundancy. If one of them is clear, that should be good enough.
Hmm, or rather than holes through the middle, make them notches or grooves on the side and shine a laser through them.
The beauty of this idea is that these tower cranes are standardised and ubiquitous. So it could be implemented immediately in almost any city in the world.
I think the problem with the one big weight is that it'd require an extra structure (a gantry) to hold it, whereas this is really simple logistically. Easy to transport and assemble.