Novel “battery” energy storage

[GrahamPlatt]

Well, CO2 is a gas... so this seemed like the right board.

https://www.rechargenews.com/energy-tra ... -1-1044755

https://renewablesnow.com/news/energy-d ... ts-763414/

https://www.powermag.com/press-releases ... 2-battery/

[88V8]

This constant pressure lark... wasn't that how the old iron gas holders worked....

There is such a plethora of competing storage/battery options now, most of them yet to scale or even emerge from the lab, as that of course needs someone to decide that this rather than that technology is the one to go for.

All very good in the long term, and necessary for the grid, but I would not like to be the one having to choose which horse(s) to back.

V8

[Mike4]

This constant pressure lark... wasn't that how the old iron gas holders worked....

Yes but this isn't how the "CO2 Battery" works.

After a fair bit of reading and skimming through waffle, I think I discovered it relies on phase-changing of CO2 from gas to liquid and back again, to store the energy as latent heat of condensation/evaporation.

[XFool]

This constant pressure lark... wasn't that how the old iron gas holders worked....

Yes but this isn't how the "CO2 Battery" works.

But perhaps on a large scale, it could be a solution? In the article he is presumably rejecting ordinary fixed size steel vessels.

After a fair bit of reading and skimming through waffle, I think I discovered it relies on phase-changing of CO2 from gas to liquid and back again, to store the energy as latent heat of condensation/evaporation.

Waffle, yes! I hate it when people say they can "Store electricity as heat" or "Store heat as electricity" etc. You can't. You can store electricity as electricity (in a capacitor?) or heat as heat you can't "store electricity as heat" or anything else, or vice versa.

[TUK020]

All very good in the long term, and necessary for the grid, but I would not like to be the one having to choose which horse(s) to back.

V8

Round trip efficiency is one of the key metrics to keep an eye on

[88V8]

This constant pressure lark... wasn't that how the old iron gas holders worked....

Yes but this isn't how the "CO2 Battery" works.
After a fair bit of reading and skimming through waffle, I think I discovered it relies on phase-changing of CO2 from gas to liquid and back again, to store the energy as latent heat of condensation/evaporation.

True, but the woffle** also says...
It does mean that rather than using the surrounding air, a large inflatable gas holder — ie, the dome — is needed to store the CO2 in a closed system. But this is a low-cost component, requiring little more than a strong but flexible PVC-coated textile, which is already manufactured for use in biogas plants.
He explains that an inflatable dome is required, rather than a solid steel tank, because the CO2 has to be at a constant pressure.
“If you have a sealed tank and you take gas out of that, you reduce the pressure. In the dome, the geometry adapts to the amount of gas we have inside and the pressure remains constant. This is a key feature of the system.”

All very good in the long term, and necessary for the grid, but I would not like to be the one having to choose which horse(s) to back.

Round trip efficiency is one of the key metrics to keep an eye on

75-80%, they say. Which is pretty good. If they can get the cost down, as they predict.
I wonder what happens to the bag when the wind blows.

V8
** I think your version is edible.

[88V8]

And just six months on, they actually have a 4MWh pilot plant running in Sardinia.
Weirdly, I can't see anything on Energy Dome's own site, but ....https://newatlas.com/energy/energy-dome-co2-sardinia/ ... the pilot plant. The company announced last year, after forming as recently as February 2020, that it would build its first plant in Sardinia and have it running by 2022. And it has, with remarkable speed. The Sardinia plant is reasonably small, storing just 4 MWh of energy and offering a maximum output of 2.5 MWe, but the company says it proves the concept works, and that it was built using off-the-shelf equipment available anywhere in the world, demonstrating that there's really no impediments to large-scale global rollout.

Unfortunately, there's no direct way for us minnows to get involved Next up: a full-scale plant storing 200 MWh of energy and delivering up to 20 MWe when needed. Energy Dome says its first full-size plant is expected to be up and running before the end of 2023, that it's already sold plants in Italy, Germany, Africa and the Middle East, and that it's moving to Series B fundraising to help it scale up as the operation goes commercial.

Anyway, good that it's happening. We need storage to make sense of our shambolic renewables.

V8

[BullDog]

And just six months on, they actually have a 4MWh pilot plant running in Sardinia.
Weirdly, I can't see anything on Energy Dome's own site, but ....https://newatlas.com/energy/energy-dome-co2-sardinia/ ... the pilot plant. The company announced last year, after forming as recently as February 2020, that it would build its first plant in Sardinia and have it running by 2022. And it has, with remarkable speed. The Sardinia plant is reasonably small, storing just 4 MWh of energy and offering a maximum output of 2.5 MWe, but the company says it proves the concept works, and that it was built using off-the-shelf equipment available anywhere in the world, demonstrating that there's really no impediments to large-scale global rollout.

Unfortunately, there's no direct way for us minnows to get involved Next up: a full-scale plant storing 200 MWh of energy and delivering up to 20 MWe when needed. Energy Dome says its first full-size plant is expected to be up and running before the end of 2023, that it's already sold plants in Italy, Germany, Africa and the Middle East, and that it's moving to Series B fundraising to help it scale up as the operation goes commercial.

Anyway, good that it's happening. We need storage to make sense of our shambolic renewables.

V8

In a not too dissimilar vein -

https://www.storelectric.com/

These folks are, or at least were, crowd funding the business, open to small investors.

[Midsmartin]

How much storage would we need? UK demand is 25GW on average, says a quick google.
Lets' handwave and say we want to be on all renewables of various sorts
We need to allow for several near windless days. There could easily be a multi-GW shortfall, unless there's lots of excess solar/nuclear, emergency gas to make up the difference. So we'd want tens to low hundreds of GWh of power stored somewhere. That'll be a huge job, however we do it, I think.

[Hallucigenia]

How much storage would we need? UK demand is 25GW on average, says a quick google.
Lets' handwave and say we want to be on all renewables of various sorts
We need to allow for several near windless days. There could easily be a multi-GW shortfall, unless there's lots of excess solar/nuclear, emergency gas to make up the difference. So we'd want tens to low hundreds of GWh of power stored somewhere. That'll be a huge job, however we do it, I think.

We talked about this recently in another thread - Ruhnau & Qvist looked in detail at 35 years of German weather records etc for what intermittency would actually look like in a 100% renewable system and their conclusion was that the potential outages are rather longer than some in the industry would admit, their worst case was a 27 TWh deficit (18 days of average load, in a country rather bigger than the UK) accumulated over a period of nearly 9 weeks around Christmas 1996. They quoted an earlier, less rigorous study which found that the worst case for the UK was needing to cover just under 7 days.

But they reckon it's doable, quoting earlier studies of storage getting down to around €30/MWh within 25-odd years, they envisage :
The storage energy capacity, which is the focus of the present paper, is 56 TWh (figure 1(b)). Most of this is hydrogen storage (54.8 TWh), while existing pumped hydro storage contributes 1.3 TWh and batteries just 59 GWh (0.059 TWh). Accounting for discharging efficiency, the storage volume translates into a maximum supply of 36 TWh electricity4. This is about 7% of the annual load or 24 d of average load—much longer than what previous time series analyses find based on their definition of a Dunkelflaute. The storage duration is 23 d for hydrogen, 6 d for pumped hydro, and 6 h for batteries

[TUK020]

Dunkelflaute

Had to google translate that one. It is not a fart where one accidentally messes oneself.