I love Gravitricity. I'm the founder of a similar startup called Terrament. We are also building gravity storage underground, but our patents are extending this idea to use autonomous, modular weights. This enables us to maximize both height and weight, which is the simple recipe for cheap gravitational energy storage.
We are also working on a seed-round of investment. It's an exciting field with plenty of room for competition. And it's so important for fighting climate change! We need to build this asap.
https://www.terramenthq.com/
How do you and Gravitricity deal with ground water? Wouldn't you require constant pumping to keep water out, using additional energy? Or can they be sealed that well to work for decades without maintenance?
But we're talking about energy storage close to consumers, not in remote locations I thought? For deployment in Europe, I don't think it'd be possible to find areas where ground water is that deep (luckily).
And pumped storage still doesn't work as you'd need surface area for new lakes. Also, not sure if you'd want to pump out huge amounts of ground water for pumped storage, lowering the water table for everyone.
My civil engineer partner could speak to this in more detail, but it's a well-understood solvable problem. You seal the shaft wall as you dig past the water table. And some small amount of pumping is used as needed.
1. So the units are actually modular, i.e., not connected. Aha. If a unit jams, it's annoying but not fatal, as all the units above it continue to be usable.
2. Since the weight units are separate, then the force on the gearing (both wall and unit) is constant and thus the wear and tear is manageable.
3. The max energy stored is when all the weights are horizontal, of course. So there needs to be a transmission line built into the shaft, along with a motor/generator per weight unit. Some cleverness needed so the transmitted power is passed to (and received from) the correct units. The sliding contact where power is transmitted would also be a major possible point of failure.
4. Yeah, that's the downside of separate modular units. Each unit now needs to transmit/receive power.
5. It would seem prudent to build two or more shafts adjacent to each other. So if there is a problem in one shaft, you can go down the other and fix it. Increases reliability significantly.
6. If the units and power transmission are waterproof, water in the shaft isn't too much of an issue. You might lose ~20% of energy storage due to the buoyancy of the water, but that's it. Might save energy not having to constantly pump out the shaft.
7. Right. Definitely need a failsafe mechanism so a unit doesn't plunge down (say, when the motor/generator clutch fails) and take out the units at the bottom.
- Regarding jams, failures, etc. These should be extremely rare, but in the event, each unit is designed to "disengage" if needed so it's just dumb weight, and modules adjacent to it will be designed to lift it. Then when the train is above ground, the unit can be swapped out for another one and repaired while the system keeps operating.
- Yup failsafe mechanisms will be built in as well.
- Yeah each unit has its own motor/generator. A power line will enter through the module's axle.
Terrament is patenting a number of different designs which enable us to maximize both height and weight to nearly 100% of a mine shaft. When you think about the physics of suspending thousands of tons inside a mile deep hole, the devil is in the details. To paraphrase Boromir, One does not simply hang a mile of concrete and steel from a cable ;) There are already some videos on the website that give away some details. We're waiting to secure funding before sharing the rest.
edit: oh sorry, I think you meant gravitricity sorry. I'm not sure what they're patenting. Also I don't think their patents are in the US.
Both solutions present heavy machinery, presumably aimed at big industrial installations.
How about home use? Could it be used small-scale, e.g. as an alternative to Tesla's PowerPack? I've long been curious about distributed energy solutions, from heating (e.g. cogeneration / CHP, heat pumps, geothermal energy, solar+battery for off-grid energy), could this be a low-cost, low-tech, low-maintenance, low-risk alternative to batteries?
At small scales, the setup costs world dwarf those of lithium by an order of magnitude. You can have a powerwall shipped to you and a local electrician install it. This, you’d have to have an engineering crew dig a shaft, unless of course you happen to own an old mine.
A basic thing to understand about electricity storage is that there are very different needs for different kinds of storage.
Flywheels from what I understand are for very shortterm storage needs, i.e. balancing out shortterm fluctuations in electricity use vs. generation. But they're unsuitable for any kind of longterm storage, because they loose power over time.
In the long run with a high-solar-high-wind-scenario we'll need some seasonal storage to get us over a couple of weeks in some circumstances. This will need some storage that doesn't loose power over time.
(FWIW I have no idea if these gravitational storage techs will play any role in that, and one can be doubtful about it.)
Apparently not that easily or the half-life would be longer than two hours... You want to try if storing energy in a flywheel while using a lot of energy for the magnetic field can outperform gravity storage?
You would need to supply a lot of power just to maintain a vacuum and levitating your flywheel. Not sure this solution would be very effective. Maybe with superconductors, but then cooling is your problem instead.
We are also working on a seed-round of investment. It's an exciting field with plenty of room for competition. And it's so important for fighting climate change! We need to build this asap. https://www.terramenthq.com/