3 ms·

If you have free energy the obvious thing to use it for is carbon capture.

bee_rider 1y ago
I wonder if desalination would be another good use. But, yeah, it is probably just a matter of how fast the processes can absorb extra power.
- cogman10 1y ago
  District heating and cooling would be an excellent sink for the power. Water needs a lot of energy to cool or heat, concentrated at a district, you could easily absorb a lot of energy at negative prices.
  - XorNot 1y ago
    Electric heating elements aren't free nor infinite in capacity. You'd pay a lot of money for a rarely used asset that has to be replaced by something else most of the time because people want their heating to be reliable.
    - nasmorn 1y ago
      But it is not horrible. A lot of people have resistive water heating for their solar setup because grid sell prices are super low and a 2kw water heater cost basically nothing.
      - XorNot 1y ago
        Which they use all the time. If you did this at a district heating level, you'd just be running an electric district heating system, resistively, which you run all the time - it wouldn't be a dump load, it would just be the load and a very inefficient one at that (compared to a heat pump). The point is all this stuff costs money to build, money to maintain, so if you don't use it most of the time the time you do needs to be incredibly valuable.
        nasmorn 1y ago
        A 10kw heating element costs 250 euros, lets double that to make it able to switch off by the smart meter. Now if you used it 1% of the year and saved 5ct per kWh you would gain 43 eur a year. Not a super convincing ROI but compared to your 10kw peak solar array a very small investment. If you used it just 2% of the year it would already be pretty good and the switch might become very cheap in the future if most houses use load steering for all kinds of things
    - cogman10 1y ago
      > Electric heating elements aren't free nor infinite in capacity. They are about as close to an ideal load as one could imagine. And capacity is easily expanded with a water tower. You can scale the total thermal energy stored and the efficiency of that storage by simply building a very large water tower. You don't even need special insulation because the water insulates itself. > You'd pay a lot of money for a rarely used asset Assuming you've converted over to district heating and cooling, it'd be frequently used as climate control for surrounding buildings. > that has to be replaced by something else most of the time What? No. District heating is the most efficient way to provide climate control, bar none. The only thing that needs to happen is setting minimum and maximum temps. Maintain the minimum temp and when negative power price events hit heat to the maximum or cool to the minimum. And if you want to get super clever, part of your storage can be sand which can store huge amounts of energy. > because people want their heating to be reliable. District heating/cooling is as reliable as plumbing. That's because that's effectively all that it is. It's super reliable. If the incoming water is 60C or 90C, it doesn't make too much of a difference in terms of heating a home. It's a proven tech. Many universities use it because it significantly reduces the heating and cooling cost for their buildings. My own city uses district heating in the downtown to great effect.
- positr0n 1y ago
  The problem is desalination plants cost billions. You're not going to make money building one then running it the 1% of the time the price of electricity is negative.
rtkwe 1y ago
The big problem there is you have these intensely capital expensive capture plants sitting idle around 75% of the time. Also the processes may not gracefully start and stop though maybe you could smooth that out by building a huge battery bank along with the CC plant to effectively run a full duty cycle with 'free' energy. That bumps the capital costs up again though so the economics get tricky.
- rcxdude 1y ago
  Yeah. Anything that's designed to use nearly-free or negative-priced energy from the grid needs to be cheap to build and easy to start and stop (The former being one of the main issues with the 'bitcoin mining as grid management' idea).
  - rtkwe 1y ago
    In theory if you run it using negative priced energy you could maybe run with older less efficient hardware that's not viable for current mining that would be much cheaper, if you can source it. I'm thinking older ASICs for BTC for example where the best in class kHash/W has moved on and the price doesn't support running the older devices but the negative price would offset that by giving a reliable return on time to offset the extra energy burned. It'd take a far amount of math to figure out if that tips it over though I don't feel like tackling haha.
ZeroGravitas 1y ago
The real low hanging fruit is energy use you were going to do earlier/later anyway but where timing isn't important. Heating water, cooling water, pumping water, charging batteries, running power hungry machines. It's half century old tech and usually the only thing missing is a financial incentive to do so.

I wonder if desalination would be another good use. But, yeah, it is probably just a matter of how fast the processes can absorb extra power.

cogman10 1y ago
District heating and cooling would be an excellent sink for the power. Water needs a lot of energy to cool or heat, concentrated at a district, you could easily absorb a lot of energy at negative prices.
- XorNot 1y ago
  Electric heating elements aren't free nor infinite in capacity. You'd pay a lot of money for a rarely used asset that has to be replaced by something else most of the time because people want their heating to be reliable.
  - nasmorn 1y ago
    But it is not horrible. A lot of people have resistive water heating for their solar setup because grid sell prices are super low and a 2kw water heater cost basically nothing.
    - XorNot 1y ago
      Which they use all the time. If you did this at a district heating level, you'd just be running an electric district heating system, resistively, which you run all the time - it wouldn't be a dump load, it would just be the load and a very inefficient one at that (compared to a heat pump). The point is all this stuff costs money to build, money to maintain, so if you don't use it most of the time the time you do needs to be incredibly valuable.
      - nasmorn 1y ago
        A 10kw heating element costs 250 euros, lets double that to make it able to switch off by the smart meter. Now if you used it 1% of the year and saved 5ct per kWh you would gain 43 eur a year. Not a super convincing ROI but compared to your 10kw peak solar array a very small investment. If you used it just 2% of the year it would already be pretty good and the switch might become very cheap in the future if most houses use load steering for all kinds of things
  - cogman10 1y ago
    > Electric heating elements aren't free nor infinite in capacity. They are about as close to an ideal load as one could imagine. And capacity is easily expanded with a water tower. You can scale the total thermal energy stored and the efficiency of that storage by simply building a very large water tower. You don't even need special insulation because the water insulates itself. > You'd pay a lot of money for a rarely used asset Assuming you've converted over to district heating and cooling, it'd be frequently used as climate control for surrounding buildings. > that has to be replaced by something else most of the time What? No. District heating is the most efficient way to provide climate control, bar none. The only thing that needs to happen is setting minimum and maximum temps. Maintain the minimum temp and when negative power price events hit heat to the maximum or cool to the minimum. And if you want to get super clever, part of your storage can be sand which can store huge amounts of energy. > because people want their heating to be reliable. District heating/cooling is as reliable as plumbing. That's because that's effectively all that it is. It's super reliable. If the incoming water is 60C or 90C, it doesn't make too much of a difference in terms of heating a home. It's a proven tech. Many universities use it because it significantly reduces the heating and cooling cost for their buildings. My own city uses district heating in the downtown to great effect.
positr0n 1y ago
The problem is desalination plants cost billions. You're not going to make money building one then running it the 1% of the time the price of electricity is negative.

rtkwe 1y ago

The big problem there is you have these intensely capital expensive capture plants sitting idle around 75% of the time. Also the processes may not gracefully start and stop though maybe you could smooth that out by building a huge battery bank along with the CC plant to effectively run a full duty cycle with 'free' energy. That bumps the capital costs up again though so the economics get tricky.

rcxdude 1y ago
Yeah. Anything that's designed to use nearly-free or negative-priced energy from the grid needs to be cheap to build and easy to start and stop (The former being one of the main issues with the 'bitcoin mining as grid management' idea).
- rtkwe 1y ago
  In theory if you run it using negative priced energy you could maybe run with older less efficient hardware that's not viable for current mining that would be much cheaper, if you can source it. I'm thinking older ASICs for BTC for example where the best in class kHash/W has moved on and the price doesn't support running the older devices but the negative price would offset that by giving a reliable return on time to offset the extra energy burned. It'd take a far amount of math to figure out if that tips it over though I don't feel like tackling haha.

ZeroGravitas 1y ago

The real low hanging fruit is energy use you were going to do earlier/later anyway but where timing isn't important. Heating water, cooling water, pumping water, charging batteries, running power hungry machines. It's half century old tech and usually the only thing missing is a financial incentive to do so.