Mines into gravity batteries

[odysseus2000]

Interesting short video of idea, by a uk firm, to use existing mines to make gravity batteries:

https://youtu.be/SS14QBMcMIo?si=m3E4qf9h4o0JXfK0

The idea of using gravity as a battery is an old one with many ancient clocks powered by lifting up weights, but if one has a free hole & modern materials it looks an interesting idea. Given that the metallurgy needed to make chains, gears, pulleys etc is well developed & presumably the lifter/generator can be at the surface for easy maintenance it looks interesting.

Renewables have come so far so quickly. We now know how to generate more power than we can use & the ability to store that power is rapidly evolving. For anyone who has experienced power cuts, rationing, high costs & all the other issues of fossil or nuclear this is all extraordinary useful & beautiful.

Regards,

[tjh290633]

I suspect that the capacity is very limited. The depth of most mine shafts is relatively low, perhaps 3km on average, and the size of the weight is limited by shaft diameter, plus the length. Compared with pumped storage like Dinorwic the capacity must be miniscule.

There may be applications which suits it, like covering short periods of power loss, but the majority problems are when the wind doesn't blow, or night time. That's when you need your gas turbines.

TJH

[Urbandreamer]

I suspect that the capacity is very limited. The depth of most mine shafts is relatively low, perhaps 3km on average, and the size of the weight is limited by shaft diameter, plus the length. Compared with pumped storage like Dinorwic the capacity must be miniscule.

There may be applications which suits it, like covering short periods of power loss, but the majority problems are when the wind doesn't blow, or night time. That's when you need your gas turbines.

TJH

Actually the VAST majority of need is "covering short periods of power loss". Or more correctly short periods of increased demand. Like when everyone was watching Eastenders and put the kettle on at the end.
https://en.wikipedia.org/wiki/TV_pickup

Electricity networks devote considerable resources to predicting and providing supply for these events, which typically impose an extra demand of around 200–400 megawatts (MW) on the British National Grid. Short-term supply is often obtained from pumped storage reservoirs, which can be quickly brought online, and are backed up by the slower fossil fuel and nuclear power stations.

Batteries, pumped storage etc are the ideal solution, but another alternative is "demand side response". I.E turning other stuff off.

Most imagine that there are no good examples of this, but with far greater communication, charging of electric busses or cars could be paused. Alternatively there are large scale users of electricity that are happy to release contracted power to the grid at short notice, provided that they either are recompensed or pay low prices at other times.
In Texas last year the electricity grid gave Riot a $31.7 million credit to turn off demand that it had contracted for.
This is somewhat contentious, as there are people who feel that such companies should not be allowed to buy electricity in the first place, let alone benefit by allowing others to use the electricity that they have contracted for.
Here is an advert from E.on trying to encourage UK businesses to become involve.
https://www.youtube.com/watch?v=MUzFd4uwvAY

[odysseus2000]

I suspect that the capacity is very limited. The depth of most mine shafts is relatively low, perhaps 3km on average, and the size of the weight is limited by shaft diameter, plus the length. Compared with pumped storage like Dinorwic the capacity must be miniscule.

There may be applications which suits it, like covering short periods of power loss, but the majority problems are when the wind doesn't blow, or night time. That's when you need your gas turbines.

TJH

If one has a mine shaft then the cost of a gravity battery is low & it does not require all the costs of building a dam & the maintenance of the water turbines & the environmental impact nor is there a need to have mountains nearby, nor is one dependent upon a volatile commodity such as gas to operate it.

If one digs a mine shaft for specific gravity batteries there is the cost & disruption of the build, but after that there is just a building on the surface, the whole working system is out of sight & has a life expectancy of forever given how there are several gravity clocks still working after centuries of use & regular maintenance.

Regards,

[Mike4]

There was a programme on R4 a year or two ago delving into this idea of weights hung in mineshafts in some detail IIRC, but I doubt I'd find it now.

They also discussed an even better idea for mines. Some are deep enough for us to fill them with water and use as thermal stores. The rock they are in will constantly re-heat the water. Use conventional heat pump technology to extract the energy as heat to the surface.

[odysseus2000]

There was a programme on R4 a year or two ago delving into this idea of weights hung in mineshafts in some detail IIRC, but I doubt I'd find it now.

They also discussed an even better idea for mines. Some are deep enough for us to fill them with water and use as thermal stores. The rock they are in will constantly re-heat the water. Use conventional heat pump technology to extract the energy as heat to the surface.

The problem with heat is that it is mot easily moved or used for anything other than heating, whereas electricity can be moved all over the place & can do many jobs including heating.

Regards,