4 ms·

If the $ per Wh cost from PV is extremely low it's also possible to use electrical heating elements to store heat in tanks of something that melts and stays hot

If the $ per Wh cost from PV is extremely low it's also possible to use electrical heating elements to store heat in tanks of something that melts and stays hot for long periods of time (for building heating purposes). Or to use cheap mid day electric power when the sun is up to generate gigantic blocks of ice that can then be used with cooling loops to air condition buildings.

toomuchtodo 4y ago
Absolutely. California alone is curtailing enormous amounts of renewables, hundreds of thousands of MWh/month (depending on the season). That is literally clean energy being thrown away (which, depending on system design, is variably tolerable; you're balancing cost, transmission congestion, and renewables offsetting fossil combustion). More transmission, more batteries, more storage, more load shifting (both temporal and geographic)? All of the above. https://www.caiso.com/informed/Pages/ManagingOversupply.aspx https://www.caiso.com/informed/Pages/ManagingOversupply.aspx
- WalterBright 4y ago
  California's oversupply problem is caused by, allow me to guess, fixed 24/7 electricity rates. These fixed rates remove all incentive for load shifting. Make electricity cheap when the sun shines, and expensive at night, and the market will shift demand. There are lots of cheap and easy ways to shift demand, I've outlined several on HN.
  - zbrozek 4y ago
    In most of California (served by PG&E) it's really expensive during the day, blisteringly expensive in the evening, and really expensive at night.
    - WalterBright 4y ago
      > really expensive during the day Doesn't really seem to fit with having surplus power.
      - sdenton4 4y ago
        PG&E also has to pay for occasionally burning half the state.
      - zbrozek 4y ago
        I blame the CPUC for basically everything regarding the crappiness of being a grid customer in California. PG&E is exactly the result you'd expect to get in our regulatory environment. Our regulators rubber stamp every tariff plan the company puts forth, and lets them get a larger profit margin on capex vs opex. So of course the optimal strategy is to run all equipment to failure and replace it with maximally expensive everything as frequently as possible. Torching the state is the business plan.
    - NavinF 4y ago
      Can confirm. Rates are 64% higher than the US average and 100% higher than a lot of states. I wonder what they do with all this money.
      - zbrozek 4y ago
        US average kWh is 14.77 cents while PG&E TOU-C starts at 37.460 and goes up to 48.902. So it's worse than you list. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_E-TOU-C.pdf https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHED...
        NavinF 4y ago
        Oh wow. Of course I can’t login to PG&E and confirm that because “Your Account is currently unavailable due to planned maintenance”. Bunch of thieves. Edit: $385.06/1033kW = $0.37/kWh A couple of servers really screws over the electric bill.
        walrus01 4y ago
        At that price of 37.4 cente per kWh and up I'm quite serious when I say that if I suddenly found myself owning a California house, I'd buy enough solar to meet my load needs, install a shitload of telecom grade 4000 cycle rated lifepo4 batteries (4.9kWh is about $1700 per module), charging setup, inverters etc and go off grid. Maybe keep the grid link attached to a meter and 100A panel hooked up to nothing if needed for municipal compliance reasons.
        zbrozek 4y ago
        That's pretty much what I'm doing, and for that reason. I don't have a great explanation for why it isn't happening faster, but I predict a substantial exodus from the California grid. Especially so in places with gas bans or among folks who electrify of their own accord.
  - Gibbon1 4y ago
    I'm more likely to be dubious about the free markets supposedly unique ability to solve problems than not. But buying electricity at $50/mwhr at noon and reselling it at $200 mwh six hours later.
    - WalterBright 4y ago
      Solar power gets expensive at night.
      - deleted 4y ago
        [deleted]
      - Gibbon1 4y ago
        Yeah that's the source of the arbitrage.
thatcherc 4y ago
One of my favorite high(ish)-concept energy storage proposals takes the "store heat in tanks of something that melts and stays hot for long periods of time" is the "sun in a box"[0] idea: use excess electricity to heat silicon up to an incandescent 4500 deg F. Later, when you want to extract the store energy, just shine some of that incandescent light into some super efficient multi-junction solar panels! Sounds pretty wild but apparently scales up very well thanks the to square cube law. [0] - https://news.mit.edu/2018/liquid-silicon-store-renewable-energy-1206 https://news.mit.edu/2018/liquid-silicon-store-renewable-ene...
- zizee 4y ago
  Cool concept! Any efficiency numbers available? I couldn't see any in the linked press release.
- bitbang 4y ago
  Isn't this just a variant of what is already being done with molten salt solar towers?
  - labawi 4y ago
    I think those don't actually have any PV in them. I.e. concentrated solar to thermal then turbines for electricity.
- ncmncm 4y ago
  You would better pump in heat, and sell the cold.
NavinF 4y ago
> electrical heating elements Very inefficient compared to heat pumps or even peltiers for that matter. > store heat in tanks Oh I already do something similar at home for sub-ambient cooling but I wouldn’t call it cheap. > If the $ per Wh cost from PV is extremely low IMO this is roughly equivalent to saying “assume that you could clone dinosaurs, and that you could fill a park with these dinosaurs, and that you could get a ticket to this ‘Jurassic Park,’ and that you could stroll throughout this park without getting eaten, clawed, or otherwise quantum entangled with a macroscopic dinosaur particle”: https://scholar.harvard.edu/files/mickens/files/thisworldofours.pdf https://scholar.harvard.edu/files/mickens/files/thisworldofo...
- alvah 4y ago
  >> If the $ per Wh cost from PV is extremely low > IMO this is roughly equivalent to saying “assume that you could clone dinosaurs, and that you could fill a park with these dinosaurs, and that you could get a ticket to this ‘Jurassic Park,’ and that you could stroll throughout this park without getting eaten, clawed, or otherwise quantum entangled with a macroscopic dinosaur particle” The premise of the article is that the $/Wh cost from PV will become extremely low, faster than most people think. Do you have a reason to believe this is inaccurate?
billiam 4y ago
A sand battery prototype in Finland is recently in the news. Has a lot of appealing features for local energy systems. https://interestingengineering.com/worlds-first-sand-battery https://interestingengineering.com/worlds-first-sand-battery

toomuchtodo 4y ago

Absolutely. California alone is curtailing enormous amounts of renewables, hundreds of thousands of MWh/month (depending on the season). That is literally clean energy being thrown away (which, depending on system design, is variably tolerable; you're balancing cost, transmission congestion, and renewables offsetting fossil combustion). More transmission, more batteries, more storage, more load shifting (both temporal and geographic)? All of the above. https://www.caiso.com/informed/Pages/ManagingOversupply.aspx https://www.caiso.com/informed/Pages/ManagingOversupply.aspx

WalterBright 4y ago
California's oversupply problem is caused by, allow me to guess, fixed 24/7 electricity rates. These fixed rates remove all incentive for load shifting. Make electricity cheap when the sun shines, and expensive at night, and the market will shift demand. There are lots of cheap and easy ways to shift demand, I've outlined several on HN.
- zbrozek 4y ago
  In most of California (served by PG&E) it's really expensive during the day, blisteringly expensive in the evening, and really expensive at night.
  - WalterBright 4y ago
    > really expensive during the day Doesn't really seem to fit with having surplus power.
    - sdenton4 4y ago
      PG&E also has to pay for occasionally burning half the state.
    - zbrozek 4y ago
      I blame the CPUC for basically everything regarding the crappiness of being a grid customer in California. PG&E is exactly the result you'd expect to get in our regulatory environment. Our regulators rubber stamp every tariff plan the company puts forth, and lets them get a larger profit margin on capex vs opex. So of course the optimal strategy is to run all equipment to failure and replace it with maximally expensive everything as frequently as possible. Torching the state is the business plan.
  - NavinF 4y ago
    Can confirm. Rates are 64% higher than the US average and 100% higher than a lot of states. I wonder what they do with all this money.
    - zbrozek 4y ago
      US average kWh is 14.77 cents while PG&E TOU-C starts at 37.460 and goes up to 48.902. So it's worse than you list. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_E-TOU-C.pdf https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHED...
      - NavinF 4y ago
        Oh wow. Of course I can’t login to PG&E and confirm that because “Your Account is currently unavailable due to planned maintenance”. Bunch of thieves. Edit: $385.06/1033kW = $0.37/kWh A couple of servers really screws over the electric bill.
      - walrus01 4y ago
        At that price of 37.4 cente per kWh and up I'm quite serious when I say that if I suddenly found myself owning a California house, I'd buy enough solar to meet my load needs, install a shitload of telecom grade 4000 cycle rated lifepo4 batteries (4.9kWh is about $1700 per module), charging setup, inverters etc and go off grid. Maybe keep the grid link attached to a meter and 100A panel hooked up to nothing if needed for municipal compliance reasons.
        zbrozek 4y ago
        That's pretty much what I'm doing, and for that reason. I don't have a great explanation for why it isn't happening faster, but I predict a substantial exodus from the California grid. Especially so in places with gas bans or among folks who electrify of their own accord.
- Gibbon1 4y ago
  I'm more likely to be dubious about the free markets supposedly unique ability to solve problems than not. But buying electricity at $50/mwhr at noon and reselling it at $200 mwh six hours later.
  - WalterBright 4y ago
    Solar power gets expensive at night.
    - deleted 4y ago
      [deleted]
    - Gibbon1 4y ago
      Yeah that's the source of the arbitrage.

thatcherc 4y ago

One of my favorite high(ish)-concept energy storage proposals takes the "store heat in tanks of something that melts and stays hot for long periods of time" is the "sun in a box"[0] idea: use excess electricity to heat silicon up to an incandescent 4500 deg F. Later, when you want to extract the store energy, just shine some of that incandescent light into some super efficient multi-junction solar panels! Sounds pretty wild but apparently scales up very well thanks the to square cube law. [0] - https://news.mit.edu/2018/liquid-silicon-store-renewable-energy-1206 https://news.mit.edu/2018/liquid-silicon-store-renewable-ene...

zizee 4y ago
Cool concept! Any efficiency numbers available? I couldn't see any in the linked press release.
bitbang 4y ago
Isn't this just a variant of what is already being done with molten salt solar towers?
- labawi 4y ago
  I think those don't actually have any PV in them. I.e. concentrated solar to thermal then turbines for electricity.
ncmncm 4y ago
You would better pump in heat, and sell the cold.

NavinF 4y ago

> electrical heating elements Very inefficient compared to heat pumps or even peltiers for that matter. > store heat in tanks Oh I already do something similar at home for sub-ambient cooling but I wouldn’t call it cheap. > If the $ per Wh cost from PV is extremely low IMO this is roughly equivalent to saying “assume that you could clone dinosaurs, and that you could fill a park with these dinosaurs, and that you could get a ticket to this ‘Jurassic Park,’ and that you could stroll throughout this park without getting eaten, clawed, or otherwise quantum entangled with a macroscopic dinosaur particle”: https://scholar.harvard.edu/files/mickens/files/thisworldofours.pdf https://scholar.harvard.edu/files/mickens/files/thisworldofo...

alvah 4y ago
>> If the $ per Wh cost from PV is extremely low > IMO this is roughly equivalent to saying “assume that you could clone dinosaurs, and that you could fill a park with these dinosaurs, and that you could get a ticket to this ‘Jurassic Park,’ and that you could stroll throughout this park without getting eaten, clawed, or otherwise quantum entangled with a macroscopic dinosaur particle” The premise of the article is that the $/Wh cost from PV will become extremely low, faster than most people think. Do you have a reason to believe this is inaccurate?

billiam 4y ago

A sand battery prototype in Finland is recently in the news. Has a lot of appealing features for local energy systems. https://interestingengineering.com/worlds-first-sand-battery https://interestingengineering.com/worlds-first-sand-battery