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Geothermal may beat batteries for energy storage

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Re: Geothermal may beat batteries for energy storage

#61

Post by Retric »

elif wrote: post #44
Retric wrote: post #16

Earlier quoted context omitted.

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…

As someone that charges lithium batteries for both cars as well as for my house, I can promise you there is 0% of me that wants to cycle my vehicle battery from 100 to 0 every day to arbitrage $1.80 of electricity.

I am suggesting we build ~twice as many batteries as EV’s alone would need. With half being used for the grid not to directly use EV’s for grid storage.

Presumably if it gets anywhere close to similar scale grid batteries would end up with dramatically different form factors and chemistry as they don’t need to worry about collisions, charging time, etc.

Re: Geothermal may beat batteries for energy storage

#62

Post by boxed »

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.…

That's just a ground heat pump no? I have the same on my house. It's pretty great. I get cooling in summer and heat in the winter.

Re: Geothermal may beat batteries for energy storage

#63

Post by Retric »

manholio wrote: post #56
Retric wrote: post #16

Earlier quoted context omitted.

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…

This is never going to happen. As a car owner, you are in a market competing with large providers of grid scale storage, that have large purchasing power, control over the battery chemistry and finer specifications of their hardware which is made to order for their needs etc. Meanwhile, you have a mobility-optimized low weight battery that has a single, monopoly supplier that will very likely treat the spare parts ma…

I am not suggesting we use EV batteries for grid storage, just ~double the number of batteries created with half going to EV’s and half going to the grid.

Of course different constraints means different chemistry and form factors etc, but that’s only going to make grid batteries cheaper.

Re: Geothermal may beat batteries for energy storage

#64

Post by ed312 »

martin_a wrote: post #11
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.

I saw a video like a month ago on YouTube where somebody pumped something like 250 liters of water on his roof (7 meters elevation, if I remember correctly) and let it run through a homebuild generator. The power capacity of that setup was like that of an AA battery, if I remember correctly. You need huge amounts of water and lots of height difference.

Based on some extremely back of napkin math (e.g. doing one of those activities where you cycle to power a light bulb) that seems pretty far off. Was the flow rate extremely low? Have a link?

Re: Geothermal may beat batteries for energy storage

#66

Post by Retric »

chriswarbo wrote: post #32
Retric wrote: post #16

Earlier quoted context omitted.

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…

Yep, it’s very possible that wildly different chemistry or even some other method wins. However, using the same battery chemistry in a cheaper form factor is the worst case. Aka if 2.3 Trillion on EV batteries works then the winner must cost less than 2.3 trillion.

Re: Geothermal may beat batteries for energy storage

#67

Post by LinuxBender »

Many of the greenhouse Youtube channels I watch do a smaller DIY version of this. They have either dark barrels of water in the greenhouse with the windows facing south to the sun, or a thin metal wall filled with clay and pipes acting as a sun-heat-battery. They pump the water through the barrels or clay battery into pipes that are under ground to store the heat. In winter time they extract the heat from the ground keeping the greenhouse warm using a combination of solar and commercial power for the pumps. Heat is also extracted from compost bins at each end of the greenhouse. This works well in extremely cold climates in Canada and Alaska. A few of these folks do all of this without using any electricity at all and somehow manage to get water moving through the pipes using heat convection alone.

I've been thinking about doing something like this but connecting it to pipes under the foundation of my home so I can get rid of the wallboard heaters or just leave them off. Electricity is the only commercial utility near me.

Re: Geothermal may beat batteries for energy storage

#68

Post by cookiengineer »

LinuxBender wrote: post #67

Many of the greenhouse Youtube channels I watch do a smaller DIY version of this. They have either dark barrels of water in the greenhouse with the windows facing south to the sun, or a thin metal wall filled with clay and pipes acting as a sun-heat-battery. They pump the water through the barrels or clay battery into pipes that are under ground to store the heat. In winter time they extract the heat from the ground…

This reminds me a lot of the Earthship community in the middle of the desert, which always focusses on smart ways of reusing water for different purposes, and by not wasting water as much as possible. The houses usually have a clean/grey/blackwater + a rainwormbox system to process fecals and reuse it for growing plants. Their air conditioning system is basically just a pipe in the ground where the hot air flows through, cools down, and automatically gets pushed through the house when they open the windows on the roof.

I was always wondering why there are no systems converting the unused electricity in potential energy by moving water to a higher ground. And more importantly: Why there are no water storages on the roof.

[1] https://www.youtube.com/watch?v=wVp5koAOu9M

Re: Geothermal may beat batteries for energy storage

#69

Post by socialdemocrat »

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…

They claim 90% efficiency, so I doubt you can compare this to heating a container and them driving a stream engine afterwards.

I suspect they are here also utilizing geothermal heat and heatpumps which allows you to increase efficiency. If you heat water that is already quite hot, then you can get more energy back than you put in. Higher temperature differentials give better efficiency.

Re: Geothermal may beat batteries for energy storage

#70

Post by ParksNet »

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.…

How effectively does the ground maintain this heat, and how much of it dissipates up and out?

As a side effect: using a heat pump to heat the ground during summer also cools the building on top! (When its at the other side of the heat pump loop)

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