Energy Vault

[RubberToe]

My favorite block stacking company is in the news today with a $100,000,000 Series B investment:

Gravity over lithium-ion: SoftBank invests $110 million in Swiss storage company Energy Vault

And a video of the system in operation:

The thing that is interesting is that the storage capacity (20MWh) as listed would only power 2,000 homes for a single day.

Stacking concrete blocks is a surprisingly efficient way to store energy

RT

 

[mblakele]

Stacking concrete blocks is a surprisingly efficient way to store energy

The round-trip efficiency of the system, which is the amount of energy recovered for every unit of energy used to lift the blocks, is about 85%—comparable to lithium-ion batteries which offer up to 90%.

[...]

Mumbai hits peak consumption in the summer when air conditioners are on full blast, whereas London peaks in winters because of household heating. Ideally, energy captured in one season could be stored for months during low-use seasons, and then deployed later in the high-use seasons.

[...]

Piconi estimates that by the time Energy Vault builds its 10th or so 35-MWh plant, it can bring costs down to about $150 per kWh. That means it can’t fill the needs of the third category of energy-storage use; to do that, costs would have to be closer to $10 per kWh.​

Sounds promising if they can cut costs.

It seems like the output energy might be choppy? Would it make sense to build a small battery buffer into the system? Maybe they already do that.

Can they use blocks from the Boring Company?

 

[RubberToe]

Can they use blocks from the Boring Company?

One of the articles I read said that they used some locally sourced material to include in the concrete blocks to reduce the block cost to 1/6 of what it would be if they used pure concrete.

RT

 

[RDoc]

ARES uses weights on train cars going up and down hill with regenerative braking for storage. They claim they can do a 2-3 GW output with 16-24 GWh at over 80% efficiency.

 

[RubberToe]

ARES uses weights on train cars going up and down hill with regenerative braking for storage. They claim they can do a 2-3 GW output with 16-24 GWh at over 80% efficiency.

That Nevada site has been in the planning stages for years. The Website says Fall 2018 construction start.

RT

 

[RDoc]

Any of these systems, or really anything else, attempting to be built in the US face years, sometimes over a decade of approvals.

Too bad the atmosphere doesn't have to go through government approvals to heat up.

 

[nwdiver]

Seems like a good way to use the 400,000 tons Uranium tailings we have. It's SUPER-Dense. Each cylinder weighs >30,000lbs.

.... We finally found a way to make 'nuclear' power affordable!

 

[SageBrush]

All these ideas that use gravity to store energy are pretty awesome. I hope the structural engineering progresses to the point of making them practical. For now, it seems like natural geography is needed to make them cost competitive.

 

[adiggs]

All these ideas that use gravity to store energy are pretty awesome. I hope the structural engineering progresses to the point of making them practical. For now, it seems like natural geography is needed to make them cost competitive.

I'd pay an entry fee to look out over a valley filled with trains going up, and trainings coming back down depending on whether it was charging or discharging. The choreography would be magnificent!

 

[RubberToe]

Another player in the gravity storage game is deploying a test system:

'Half the price of Li-ion': new gravity-based energy storage concept heads for trials | Recharge

 

[SageBrush]

Another player in the gravity storage game is deploying a test system:
'Half the price of Li-ion': new gravity-based energy storage concept heads for trials | Recharge

Seems like a good use for an abandoned mine shaft, although darned if know how they are going to maintain and fix it.

 

[RubberToe]

Seems like a good use for an abandoned mine shaft, although darned if know how they are going to maintain and fix it.

Seems just like the Energy Vault, except underground. But there are a lot more places to build up than down. Maybe the draw to using a mine is that it goes much deeper than you could stack concrete blocks? But the concrete block scheme has a larger surface area versus a mine shaft, so certainly more overall weight as a function of height (e.g. 300 blocks stacked up at 300 feet hold more energy than a single block sitting at the top of a mile deep mine shaft).

RT

 

[themountinman]

Hmm... I wonder if they make you pay for the roughly 2800 35 ton blocks you'll never use, since once the height of the outside rings reaches the height of the supply ring (around 14 layers), there's very little potential energy left to capture.

Of course, at that point, the battery is nearly exhausted and would need to start 'recharging'. But the greatest potential energy is achieved by restoring the blocks to the maximum height. So, it appears the best choice would be to rebuild the supply ring. So, about a third of the blocks aren't ever needed.

Also, every trip of the block from max potential to min potential requires TWO crane movements; one out of every two crane movements is an empty. That doesn't seem so efficient.

There about 8000 blocks in the tower as depicted. It's seems likely that over the possible hundreds of thousands of trips per month, eventually one of those blocks or a crane will fail, and send 35 tons descending down on the pile. At the very least, a failure will prevent the affected landing area from being used, as any debris will disrupt the precision placement of incoming blocks. This could drop the power output significantly, and repair would likely be pretty expensive (in lost time alone). And better hope no one's around when a failure happens.

This is an idea (reality) that looks kinda neat on paper, but doesn't really seem very practical. It's like a mammoth, vertical, bowling alley with 8000 pins. What could go wrong?

 

[RubberToe]

New article out today and also discusses Gravitricity:

Gravity Could Solve Clean Energy’s One Major Drawback

Finding green energy when the winds are calm and the skies are cloudy has been a challenge. Storing it in giant concrete blocks could be the answer.

www.wired.com

 

[iPlug]

Energy Vault - Enabling a Renewable World™