Mechanical Energy Storage System

[Wayne Mack]

Here is an interesting alternative to batteries for large scale energy storage.

Gravity could solve renewable energy's biggest problem | CNN Business

Energy Vault's gravity-based technology can store wind and solar power longer than batteries.

www.cnn.com

 

[hitmouse]

This is essentially what happens at Dinorwig in North Wales. Pumped storage hydroelectricity uses water instead of concrete blocks on cranes.

 

[Christine Wheelwright]

Yeah, I'm just not feeling it! I mean its technically correct - power is consumed raising the load and generated during lowering. But there are a million mechanical energy storage schemes like this one being proposed. Some involving mine shafts, some involving old locomotives on inclines, some involving compressed air, some involving flywheels. These are potentially more efficient than the old favorite - pumped water energy storage (reservoirs on hills) - but nowhere near as scalable. Also, large lithium battery arrays have become price competitive against these mechanical solutions (which could be a bad thing - if lithium supply is indeed limited then we should reserve it for applications that demand its inherent features - like electric cars).

 

[CupofJoe]

If some people object to Wind turbines on aesthetic grounds, I can't see anyone being in favour of this.

 

[AllanR]

if lithium supply is indeed limited

it might not be as limited as it seems Scientists have cost-effectively harvested lithium from seawater

 

[Wayne Mack]

This is essentially what happens at Dinorwig in North Wales. Pumped storage hydroelectricity uses water instead of concrete blocks on cranes.

However, water is often a scarce resource. I am not sure that tying up quantities of water for any extended period of time would be practical in drier areas. Also by using a solid, containing walls do not need to be built, and, if the solid is higher density than water, then a smaller storage structure would be needed to retain the same amount of energy. This may be a simpler solution to the energy storage problem.

 

[Wayne Mack]

large lithium battery arrays have become price competitive against these mechanical solutions

I wonder if battery technology could suffice to handle the scale of the energy storage issue. I also question the longevity of batteries. Battery storage capacity decays over time and current predictions for battery life in electric cars puts the duration at 10-20 years. Physical structures would not have decrease in capacity over time, much of the structure could be extremely long lived, and the parts that do wear out (winches, cables, etc.) could be replaced incrementally (although, we haven't done a good job with this for other infrastructure such as roads and bridges). I am a big believer in simpler is better and this type of mechanical solution seems to fall in the simpler realm.

 

[Venusian Broon]

Look up Adam Something's 'The Energy Vault is a dumb idea' on YouTube for a pretty scathing response to this idea.

I tens to agree with him - it's not a particularly simple nor cost effective solution

 

[psikeyhackr]

How much energy is used up on advertising, neon signs and junk like that? How much energy would we save by just making that illegal?

 

[Robert Zwilling]

Lithium batteries use materials that are extremely chemically active which can lead to fires and explosions. Until a safe, high power battery is produced, current batteries are somewhat impractical from a safety point of view. Physically separated by their current use configurations the fires are somewhat manageable. Putting thousands of large configuration fully charged batteries together in close quarters probably isn't such a good idea. There is a thin film plastic based battery that works in the lab for 10 years now, but apparently no way to scale up the manufacturing process. There is also a perfectly safe saltwater battery that has been around for awhile, but its a low density power device which requires a lot of space.

 

[mosaix]

I’ve seen the suggestion of storing energy from wind farms in the form of compressed gas.

 

[hitmouse]

However, water is often a scarce resource. I am not sure that tying up quantities of water for any extended period of time would be practical in drier areas. Also by using a solid, containing walls do not need to be built, and, if the solid is higher density than water, then a smaller storage structure would be needed to retain the same amount of energy. This may be a simpler solution to the energy storage problem.

Water is certainly scarce in some parts of the world, but it is very plentiful in others. Accepted that solids may have much higher density than water, but I have trouble believing that any block and crane mechanism could retain more energy than a reasonably-sized reservoir with a decent drop.

 

[Christine Wheelwright]

I’ve seen the suggestion of storing energy from wind farms in the form of compressed gas.

Compressed gas storage is very inefficient. Meaning the energy out is very low compared to the energy in. The original poster's hoisted weights could be very efficient (maybe even 80% to 85%), but difficult to apply on a large scale. Lifting one metric tonne 100 meters straight up only represents 1 million joules. Enough to keep a 1kW electric space heater running for about 13 minutes. This doesn't cut it on the kind of scale the people who run the grid need to be thinking.

Pumped water for the win! You need a hill close to a body of water.

 

[Swank]

Pumped water for the win! You need a hill close to a body of water.

Or an enclosed bay filled by the tide, if you want to produce the energy for free.

But putting boiler systems in orbit requires no storage system because you just beam the power to where it is on peak.

 

[mosaix]

This is essentially what happens at Dinorwig in North Wales. Pumped storage hydroelectricity uses water instead of concrete blocks on cranes.

I went round the man made underground cavern containing the power station many years ago when they did tours (maybe they still do). It’s absolutely enormous.

The inlet valves from the upper storage pond are an engineering marvel. They’re circular with a swivel hinge across the centre. As the valve closes the water pressure on the top half, as it swivels down, is equal to the water pressure on the bottom half, as it swivels up. And vice versa as it opens. Simple really.

 

[.matthew.]

Look up Adam Something's 'The Energy Vault is a dumb idea' on YouTube for a pretty scathing response to this idea.

I tens to agree with him - it's not a particularly simple nor cost effective solution

That's literally the video I was thinking of when I saw this post. It sums up why the design is patently ridiculous.

The concept isn't bad though and if you were to use weights instead of water, that video had a few good fixes that'd make it work.

 

[Brian G Turner]

New Hollow Mountain renewable energy project planned

Drax is seeking permission for the scheme adjacent an existing underground power station in Argyll.

www.bbc.co.uk