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Geothermal may beat batteries for energy storage

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Re: Geothermal may beat batteries for energy storage

#31

Post by killjoywashere »

jillesvangurp wrote: post #24
moffkalast wrote: post #8

Earlier quoted context omitted.

I wonder if it would be possible to scale down pumped hydro to something the size of a tall water tower. Probably not worth it due to the small height difference and volume, and you'd also lose efficiency due to the smaller turbine, but I still do wonder what the actual figures are like for something like that. Especially in cost per kWh stored compared to lithium.

It can work, it's just a cost equation. You need a large amount of mass to get meaningful amounts of energy stored. So pumped hydro is nice because you are basically using natural reservoirs and some cheap pumps and pipes. A water tower needs to be built first and only stores a limited amount of potential energy. The problem is not the efficiencies but the cost of building a big enough tower. A tower with the same ca…

Why would you need a water tower? If you're in flat geography at sea level, you could probably access tidal energy to drive generators. If you're flat and far from water, couldn't you dig a shallow hole and a deeper hole, and put the generator and pumps in between? I mean, even in Kansas it's not that hard to find an elevation difference of 50 feet.

Re: Geothermal may beat batteries for energy storage

#32

Post by chriswarbo »

Retric wrote: post #16
jillesvangurp wrote: post #7

Interesting option. It's all about the cost and efficiencies in the end. Converting electricity into heat and then back into electricity is a lossy process that is constrained by the second law of thermodynamics. Basically generating heat is easy and efficient. But converting it back to electricity is typically less than 50% efficient. Basically, it's several energy conversions in one process: you use electricity to…

Using batteries for the grid requires roughly the same amount of batteries as EV’s do. A 100kWh battery pack for a car * 1,000 charge cycles / 25 years = 4,000 kWh of battery per year * ~290 million cars. That’s enough to store almost 1/3 of all current electricity used in the US while ignoring busses and farm equipment etc. Of course actual cost depends on how much storage we need and future battery prices but addin…

> Using batteries for the grid requires roughly the same amount of batteries as EV’s do

EVs have much harder constraints. The most obvious is that they need to move around (requiring high energy density, for both mass and volume); they also need to cope with sporadic charging times, and be reasonably fast to charge. It's very hard to compete with the leading Lithium-ion batteries in this space.

Grid storage isn't as constrained. Larger, heavier batteries are fine since they're just going to sit in one place. It's also easier to accomodate awkward/slow charging requirements, since they're always plugged in to the grid, and can be coordinated with other electricity sources/sinks if needed.

This allows different chemistries to compete, based on e.g. price, longevity, safety, etc.

Re: Geothermal may beat batteries for energy storage

#33

Post by rglullis »

swayvil wrote: post #30
nicoburns wrote: post #28

Earlier quoted context omitted.

I'm not convinced competition is a euphemism for fighting. Competition can be friendly.

You got any examples of "friendly, nonfighting type competition" in the business world?

All of the oligopolies? Do you really believe that, e.g, tech companies are "fighting" each other? What about Big Pharma? The Food industry?

In any case, you are arguing semantics. Competition can be friendly.

Re: Geothermal may beat batteries for energy storage

#34

Post by tyfon »

There is a school close to where I live that does something like this.

During the summer they heat the bedrock using solar panels (thermal and electric via a heapump) to heat the bedrock far down using water pipes. In winter they extract this energy for heating, electricity and hot water making the school self sufficient for energy.

Here is a write-up from the municipality about it, but it's in Norwegian

https://www.drammen.kommune.no/om-kommunen/aktuelt/unikt-pro...

Edit: translated version

https://www-drammen-kommune-no.translate.goog/om-kommunen/ak...

Re: Geothermal may beat batteries for energy storage

#35

Post by moffkalast »

empyrrhicist wrote: post #22
moffkalast wrote: post #8

Earlier quoted context omitted.

I wonder if it would be possible to scale down pumped hydro to something the size of a tall water tower. Probably not worth it due to the small height difference and volume, and you'd also lose efficiency due to the smaller turbine, but I still do wonder what the actual figures are like for something like that. Especially in cost per kWh stored compared to lithium.

Water is just too heavy. Pressurized air would be easier.

I think there's a start-up in Italy working on pressurized CO2 which apparently has some major benefits over using air.

Re: Geothermal may beat batteries for energy storage

#36

Post by majou »

tyfon wrote: post #34

There is a school close to where I live that does something like this. During the summer they heat the bedrock using solar panels (thermal and electric via a heapump) to heat the bedrock far down using water pipes. In winter they extract this energy for heating, electricity and hot water making the school self sufficient for energy. Here is a write-up from the municipality about it, but it's in Norwegian https://www.…

Same idea in Alberta: http://dlsc.ca/borehole.htm

Re: Geothermal may beat batteries for energy storage

#37

Post by ksidudwbw »

jillesvangurp wrote: post #7

Interesting option. It's all about the cost and efficiencies in the end. Converting electricity into heat and then back into electricity is a lossy process that is constrained by the second law of thermodynamics. Basically generating heat is easy and efficient. But converting it back to electricity is typically less than 50% efficient. Basically, it's several energy conversions in one process: you use electricity to…

Not used for electricity just cooling and heating with heat pumps

Re: Geothermal may beat batteries for energy storage

#38

Post by adev_ »

tyfon wrote: post #34

There is a school close to where I live that does something like this. During the summer they heat the bedrock using solar panels (thermal and electric via a heapump) to heat the bedrock far down using water pipes. In winter they extract this energy for heating, electricity and hot water making the school self sufficient for energy. Here is a write-up from the municipality about it, but it's in Norwegian https://www.…

In a smaller scale, this is also what the French solar panel manufacturer Dual Sun [^1] sell with their geothermal+hybrid panels solution for individual houses.

- In winter, heat is generated with a geothermal heat pump and an horizontal underground network of pipe.

- In summer, the thermal solar excess energy is used to warm up the soil that has been cool down during winter and also to avoid permafrost.

[1]: https://dualsun.com/applications/pompe-a-chaleur-solaire/

Re: Geothermal may beat batteries for energy storage

#39

Post by VaxWithSex »

moffkalast wrote: post #35
empyrrhicist wrote: post #22

Earlier quoted context omitted.

Water is just too heavy. Pressurized air would be easier.

I think there's a start-up in Italy working on pressurized CO2 which apparently has some major benefits over using air.

Yes, higher liquifying point.

Re: Geothermal may beat batteries for energy storage

#40

Post by Someone »

jillesvangurp wrote: post #19
Someone wrote: post #12

Earlier quoted context omitted.

If you then use the lithium ion to produce heat, things start looking less favorable for it. Also, I think the “geothermal” part of this means your ‘battery’ gets partly charged for free.

This article is about storing energy generated using renewables in reservoirs; not about tapping into geothermal energy. The issue with geothermal is not that the energy isn't there but that getting to it involves a lot of expensive infrastructure. It's cost effective in some parts of the world and not really cost effective (relative to cheaper solutions) in other parts of the world. Using this instead would mean hav…

> This article is about storing energy generated using renewables in reservoirs; not about tapping into geothermal energy.

I think it’s about both. They plan to create reservoirs that heat water _and_ use them to store warm water. Also for the latter the outside heat source will provide energy.

FTA: Enhanced geothermal systems (EGS) get around this geographical limitation by creating artificial reservoirs. Developers create fractures in hot, dry rock formations by drilling into or melting the rock, and then injecting water into the fissures. Production wells bring the heated water up for producing electricity. “For scales necessary to contribute to national or global electricity decarbonization, we need to be able to extract geothermal heat outside of conventional formations,” Ricks says.

[…]

Once these EGS systems are in place, they would be ideal for storing energy as well as producing electricity. Excess wind or solar energy could be used to inject water into the artificial reservoirs

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