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Geothermal may beat batteries for energy storage

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Re: Geothermal may beat batteries for energy storage

#111

Post by cinntaile »

teucris wrote: post #93
jonstewart wrote: post #91

Earlier quoted context omitted.

Selling PV electricity back to the grid is almost always many times worse, depending on state incentives, than consuming the electricity. For example, my utility sells electricity to me at 9 cents/KWh, but only buys from me at 2.5 cents, and charged me a fixed monthly fee for the meter to boot. If the commenter’s house doesn’t have gas, then it doesn’t seem to make sense to install it, and the price differential in t…

Huh. We have a 1:1 credit system here in Washington.

Considering solar owners are all pushing electricity onto the grid at the same time, when it is needed the least, such a system doesn't make sense. There are real costs associated with getting rid of all that unwanted energy.

Re: Geothermal may beat batteries for energy storage

#112

Post by psadri »

cookiengineer wrote: post #68
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 thro…

energy storage density of heating water >> lifting water.

1m^2 of water heated by 50C (20C → 70C) = 58KWh

lifting 1m^2 of water by 10 meters (~ 3 stories!) = 0.03Kwh :-(

Re: Geothermal may beat batteries for energy storage

#113

Post by cupofpython »

merely-unlikely wrote: post #90
cookiengineer wrote: post #68

Earlier quoted context omitted.

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 thro…

> I was always wondering why there are no systems converting the unused electricity in potential energy by moving water to a higher ground There are a bunch of pumped storage facilities around [1]. But they work best at massive scale, so suitable locations are somewhat limited. Plus they are expensive to build and often face environmental protests (similar to building dams). Still, it's a solution I'm a fan of. [1] h…

emphasis on massive scale.

Moving 500,000 kg (over 1 million pounds) 7.5 meters (~25 feet aka the height of a house) will give you about 10 kWh of energy. This is equivalent to running a 425W device all day, like a small air conditioner. The relationship is linear. Double the weight or the distance to double the energy. All of the metal at a scrap yard I know of amounts to less than half that weight, for reference.

I'm also a fan because pumped storage is a really interesting storage method, but it is beyond niche. It is very tough to move that kind of weight around efficiently for what you get back. Pumping water to great heights is not easy either. (see also: moving rail-carts up a mountain)

Re: Geothermal may beat batteries for energy storage

#114

Post by RosanaAnaDana »

dmurray wrote: post #81
ed312 wrote: post #64

Earlier quoted context omitted.

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?

250 litres x 7 metres is 1750 kilogram-force-metres. Wolfram Alpha [0] says this is about 5 Watt-hours, and gives some other handy comparisons: > ≈ 0.45 × metabolic energy of one gram of fat ( ≈ 38000 J ) > ≈ 0.63 × energy released by burning 1 gram of ethanol ( ≈ 27000 J ) > ≈ metabolic energy of one gram of sugar or protein ( ≈ 17000 J ) > ≈ (0.02 to 0.09) × typical kinetic energy of a car at highway speeds ( 20000…

Would you be able to help me figure out the gravitational potential energy of the red hill tanks?

https://www.epa.gov/red-hill/what-red-hill-bulk-fuel-storage...

They were recently decommissioned due to leaks, but I've often wondered if they could be repurposed as gravity battery storage.

edit: if you want to check my math. I calculated the tanks at ~567 million liters, and am saying there is 120 meters of vertical distance.

They would be equivalent to a 0.1856 GW h (gigawatt hours) battery if repurposed in this way. https://www.wolframalpha.com/input?i=567810000*120+kg+metres...

Re: Geothermal may beat batteries for energy storage

#116

Post by jammaloo »

cookiengineer wrote: post #68
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 thro…

There is a great youtube channel that tests out different energy storage and harvesting setups, a lot of them focused around water.

This is one where they use solar to pump water to the roof, and then use the potential energy overnight: https://www.youtube.com/watch?v=CMR9z9Xr8GM

Re: Geothermal may beat batteries for energy storage

#117

Post by bagels »

spywaregorilla wrote: post #115

It's interesting to wonder how profoundly different the world would be if everyone had access to geothermal energy at the scale of somewhere like Iceland.

I know they heat their homes with the geothermally warmed water, but their electricity rates don't seem to be significantly different than most places.

"Iceland, March 2022: The price of electricity is 0.139 U.S. Dollar per kWh for households."

Re: Geothermal may beat batteries for energy storage

#118

Post by cogman10 »

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…

My uncle had a home like this built in the 70s. His whole home was solar heated.

AFAIK, it worked pretty well year round.

Solar heating is one of the most efficient usage of solar energy. The reason we don't generally do it more is because it's expensive and can be a headache to maintain (what happens when you spring a leak or your PVC pipes become brittle from sun exposure? Or when your heatbox ends up fogged or dirty).

In that case, it can be a lot simpler to rely on heat pumps and geothermal energy storage.

Re: Geothermal may beat batteries for energy storage

#119

Post by cogman10 »

cookiengineer wrote: post #68
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 thro…

> Why there are no water storages on the roof.

Depends on the area, but sometimes collecting rain water is illegal.

The other issue is that when dealing with rainwater, you need to clean it. Untreated, rainwater will likely develop a bad case of algae.

Re: Geothermal may beat batteries for energy storage

#120

Post by drewbeck »

Someone wrote: post #102
drewbeck wrote: post #42

Earlier quoted context omitted.

Yeah that last line is key — they’re not creating heat with the excess energy, they’re pumping water. The article doesn’t have much specifics but the implication is they’re achieving much higher efficiency than if they were doing electricity → heat → electricity

It’s not clear from the article, but I think they’re aiming to do both: create new geothermal sources by drilling (running, I guess, some of the risks of fracking) _and_ storing excess energy as heat in those sources.

yeah they're creating geothermal reservoirs to pump with water to then extract steam. any excess energy generated from renewables gets used to pump additional water into the reservoir.
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