Engineering360: "Massive, Gravity-Based Battery Towers Could Solve Renewable Energy’s Storage Problem"

Cynical as I am, I think that's a great concept!

These could be located almost anywhere and be effective.

Certainly thinking outside the box . . .

Lots of moving parts. Violates the KISS principle.

Looks expensive too. How much greenhouse gases are emitted when they make all that concrete?

Looks great to me. I was daydreaming about a system in which a single massive chunk of rock was carved out and raised and lowered in place to store energy, but this system solves a lot of problems.This seems to be incredibly scalable. You add capacity by making the tower taller, and/or by adding cranes and blocks, and/or maybe just swapping out for heavier blocks.

It doesn't have to be out on open land. I think you could place it inside an open pit mine. I know an enormous calcite mine in New Jersey that produces concrete, and the area is solid calcite. You could just saw more blocks from the pit whenever you need more capacity and don't bother with making them from concrete.

It would be interesting to make the blocks different colors too, and have algorithms that created different patterns or pictures in the tower every day as it was built.

i wonder if Musk could make bigger Boring bricks?

I believe my idea would be much better at having a constant source of energy. The idea is to have a world wide grid of solar panels. As Jimmy Buffet would say, it's sunshine somewhere.

Curse you Papa, How dare you think globally. Where is your selfishness?

This looks expensive and problematic...and adds substantially to the cost of already expensive "Renewable energy" and adds to the growing, already huge, footprint...How long before those bricks start disappearing, what about maintenance costs, for a large structure very little actual capacity...

Anything using gravity as energy storage will have to be massive...

From 2013...

Such is the problem with letting small minded humans make these really big decisions.

The same mindset that said you can't land a rocket on a barge in the middle of an ocean.

The problem isn't so much whether a concept is technically feasible or not, it is whether or not it is economically feasible. How much are 'we' willing to pay?

However, there are people out there who seem to think if you spend enough money on something, you can violate the laws of physics as we currently know them.

If you spend enough money you seem to be able to violate every other law, why not physics?

People do not want to fully cost out what their fossil fuel addiction costs.

Because it is much harder to corrupt physics than it is to corrupt people.

Costs of this 'addiction' are highly dependent on who you ask. Lots of salt is required on ALL sides.

Interesting post. It make me think of comparing the train system with the tower system. I know you only brought it up to point out the system has to be massive, but I started thinking about the relative advantages.

I don't think the tower system is as expensive and problematic as you say. And any kind of energy storage will add to the cost of renewable power, but if it makes it feasible then the cost can be worth it. Like adding brakes to a car makes it more expensive and doesn't make it go any faster, but you usually want to pay for them anyway.

The tower is cheap to install. Build the tower and install the generators, then bring in as many blocks as you need and the cranes just start working. You could even use some of the blocks to anchor the tower. No railroad tracks, no bridges over creeks or gulches or roads, no fire roads or hiking trails or horse trails to cross, no need to buy or lease miles of connected land, no grazing rights or access problems, no need to look out for livestock or wildlife or hikers up in the mountains. And if you remove the blocks and towers, the land is just as good as before.

The tower system doesn't need a mountain, especially a mountain that is close to the grid. You could put it inside a city if you wanted to, hidden inside a tall building. You could even put it underground if you wanted to. You could put them out on the prairies and plains where there is a vast amount of wind but no mountains.

The tower system needs far less land than the train. The train system needs a pretty massive train yard at the top and bottom of the tracks, several sets of tracks and an access road. You'd probably need a right of way over 100 yards wide for its whole length. For a reasonable railroad grade, you'd need a considerable distance. If a tower were 100 yards wide, on the land needed for a mile of railroad you could install 170 towers, and that doesn't include the rail yards at top and bottom.

Also, it seems to me that there would be far less friction in the cables than in the train cars on the rails, but that is only an impression.

Also, the solid blocks in the tower system are far simpler than the train cars and far easier to remove from the system. In the train scenario, if you had a malfunctioning or derailed car, you would have to halt the operation on that track long enough to bring in another car or a locomotive to haul it out. In the tower system you already have a perfectly good crane right overhead. Three of them, in fact, in the video.

I think the electrical connections are simpler in the tower system. You just need one connection to each generator, and the generators are stationary. In the train system you have to get the energy from the train car that may be a mile away. Either you have electrical connections that parallel each set of train tracks and the cars each have their own generator, or the train has mechanical cables that stretch the entire mile between the car to spin the generator, and to pull the train car up.

I'm also thinking about runaway trains. Probably more dangerous and destructive than a dropped block of concrete.

I'm not sure what you mean by a block disappearing. In any case, it would be far easier to replace a block of concrete than a train car. (I have a vision of block thieves breaking in and prying a 35 metric ton concrete block from the top of the outer ring, dropping it onto their getaway flatbed trailer, and trying to drag the trailer out of the brand new hole it would be a part of. Probably not what you had in mind. )

Anyway, thanks for posting that link about the trains. Very interesting.

I'm confused. If the system is in use, those bird nests would be flattened by a stack of 35 metric ton blocks every day.

When you say they would last for a few hours, what are you referring to? As I understand them they would be stacked up every day and unstacked every night.

What size block and how far would it need to fall to generate enough power for my house? I use about 1800 kwh per month in the summer. The block and rigging could be enclosed in a structure with appropriate safeguards. How much solar power would I need? How much square footage would be required for the solar panels?

It's evident that I'm proposing a stand alone system. I can't do the math because I get messed up in the units conversions especially when it comes power conversions.

I'm sure someone out there can do the math for me.

Have some fun today,

PAPADOC

Some of the numbers they supply can give a basic idea of sizes. At 35 metric tonnes/block that works out to 77,000 lbs. Tower cranes for building construction are 200-250 ft high so a single block lowered to the ground from that height would generate 7.25 kWhr. (77,000 lbs * 250 ft / 2,655,000 ft*lbs/kWhr) Your house would require about 250 blocks to keep it going all month or about one block every3 hrs continuously, with it as your only energy source. As far as solar panels are concerned, commercial panels typically have an output of 15-20 W/sq.ft and solar installations are rated as having an output of 100-125 Whr/sq ft/day so your house would need 500-600 sq ft of solar panels to power it, maybe half of your total roof area. (Note your power consumption is about twice the national average of 800-1000 kWhr/month, I am assuming a large HVAC load :). A realistic commercial system would be sized a little differently since you are consuming a portion of power/energy during the day while the sun is shining so you would only need to store a fraction of your energy needs from the day to the night. In your case you would need to lower 6 blocks every evening/night and restack them every day to keep your household humming along. Multiply by the number of homes a single tower needs to serve and you can figure out how many blocks need to be moved to keep the neighborhood powered up.

Yeah, I totally agree. These people are nuts! Tidal lift would be far more efficient.

Tidal lift is comparable but the size of installation can be daunting. Because the lift height is limited (most coastal areas are 3-6 ft) you need to build a float that displaces 3.85 million lbs of water moving 5 ft to equal the energy storage of a 77,000 lb block moving 250 ft. Now the ocean is big but a boat hull of ~2000 tons displacement is not free either. You are limited to near shore areas, undersea power cables (a serious engineering issue for marine wind turbines), etc so you have to carefully examine the entire system cost. Also this is an apples and oranges comparison. The tidal lift I described is a energy generation system not a storage. For a true tidal "energy storage" system, the hull/float would have to be locked down at low tide, the tide would have to come in and your release the float. You extract energy from the float bobbing back to the surface. But this is not true independent storage because if you don't use that power at high tide, the tide will go back out and you get nothing for that cycle.

Actually there is no reason it could not be a constant process. True that the shore area would be an issue however with an enormous surplus of uninhibited islands this could be rectified. Transportation of energy is always an issue.

Interesting, but I wonder about the efficiency of the system. You have some losses in the motor, which could also be the generator. Losses due to bending to of the cable both at the motor/generator drum and at the sheaves on the blocks. Then there are inertial losses as the crane trolleys and concrete blocks are moved in and out.

I also wonder about the security of the attachment to the concrete blocks. Are the "legs" stiff enough to keep them from flying out and dropping the blocks?

What keeps a stack of blocks from tipping over? Are there interlocking ridges on the blocks?

This arrangement isn't exactly beautiful, so I imagine that NIMBY will be a factor.

At first glance this system may be usable. However, viewing a animated example is no proof of concept. Also, no mention is made of cost per kilowatt. I have no problem with the development of such systems, but just like solar panel and wind turbine farms, I don't believe that these types of projects should be subsidized by taxpayer money. It was mentioned that these energy storage facilities would have a manageable footprint. The need for sprawling wind turbine or solar panel farms will still be necessary.

Are there any working examples (not small scale models) that could be observed?