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Or the lecture is that we should go harder on individuality. Ironically this same blog has a post titled "Review: Moixa Solar Battery". If you have a 100kWh bat

Or the lecture is that we should go harder on individuality. Ironically this same blog has a post titled "Review: Moixa Solar Battery". If you have a 100kWh battery at home to tide you over the 3 days it's cold (and electricity costs $9/kWh) but can otherwise directly access the wholesale pricing, what is not to like? I'm not sure if anyone has done the math on what kinda timescale you are looking at for return on investment with a 100kWh battery, but given that most electricity grids in the world have e.g. different day and night rates, there is an obviously untapped market for arbitrage.

gruez 6y ago
>there is an obviously untapped market for arbitrage. But if there was an arbitrage opportunity, wouldn't a company be already on top of it[1]? I'd imagine that a company would have greater economies of scale to operate such a system compared to a home user. My guess is that there aren't many people who have solar panels/wind mills, 100kWh batteries, and aren't connected to the grid, because it's much more cost-effective to use the grid as your battery (that is, sell into it when you're generating power, and buying from it when you're not). [1] insert joke about a pair of economists finding a $20 bill on the sidewalk
- shiftpgdn 6y ago
  My cousins husband works for a company in Texas that provides massive generators to commercial energy users at cost with the catch they're allowed to run the generators to feed the grid when the cost of energy is higher than the cost to run the generators.
jodrellblank 6y ago
A 100kWh battery would run a 1kW bar heater (and nothing else) for 4 days. That's probably enough to heat one room and keep you alive, but it won't be giving you the full electric shower, cooking food, warm house and pipes not freezing experience. Even moreso if you want to keep some reserves in case it needs to last more days. > "I'm not sure if anyone has done the math on what kinda timescale you are looking at for return on investment with a 100kWh battery" A long one. 100kWh will cost you maybe $70,000 (e.g. 10x of these https://www.amazon.com/48-VDC-Kwh-Battery-Pack/dp/B079348MM1 https://www.amazon.com/48-VDC-Kwh-Battery-Pack/dp/B079348MM1 ) (If it's not LiIon, but is lead-acid to be cheaper, you won't want to be using much more than 50% of it before it causes problems). At $1/kWh from the mains, about 8 years of mains electricity to buy it. At $0.25/kWh, 32 years.
- cozzyd 6y ago
  That has 2500 charge cycles too so...
  - jodrellblank 6y ago
    What do you mean? In this scenario of 4 days heating per charge that makes 10k days which is 27 years, and that seems a reasonable sort of lifetime for a product - probably beyond any warranty period it has.
    - cozzyd 6y ago
      Well it limits the time horizon over which it can possibly become cost effective (you have to save more than $28 / charge on average).
cool_dude85 6y ago
Using a big battery in this way under a time of use rate isn't arbitrage, its exactly what the utility company wants you to be doing. That's why they incentivize you to do it with a nice rate. If you spend 70k on a battery and then think you're getting one over on the power company by giving them 100 kWh of storage for the price of the cost difference on their daytime and nighttime rate, the power company is laughing all the way to the bank.
- deleted 6y ago
  [deleted]
- imtringued 6y ago
  Although I agree with you, you haven't really explained why it's not arbitrage. If you are not selling back to the grid all you are doing is load shifting. Arbitrage involves buying and selling to reduce spreads.

gruez 6y ago

>there is an obviously untapped market for arbitrage. But if there was an arbitrage opportunity, wouldn't a company be already on top of it[1]? I'd imagine that a company would have greater economies of scale to operate such a system compared to a home user. My guess is that there aren't many people who have solar panels/wind mills, 100kWh batteries, and aren't connected to the grid, because it's much more cost-effective to use the grid as your battery (that is, sell into it when you're generating power, and buying from it when you're not). [1] insert joke about a pair of economists finding a $20 bill on the sidewalk

shiftpgdn 6y ago
My cousins husband works for a company in Texas that provides massive generators to commercial energy users at cost with the catch they're allowed to run the generators to feed the grid when the cost of energy is higher than the cost to run the generators.

jodrellblank 6y ago

A 100kWh battery would run a 1kW bar heater (and nothing else) for 4 days. That's probably enough to heat one room and keep you alive, but it won't be giving you the full electric shower, cooking food, warm house and pipes not freezing experience. Even moreso if you want to keep some reserves in case it needs to last more days. > "I'm not sure if anyone has done the math on what kinda timescale you are looking at for return on investment with a 100kWh battery" A long one. 100kWh will cost you maybe $70,000 (e.g. 10x of these https://www.amazon.com/48-VDC-Kwh-Battery-Pack/dp/B079348MM1 https://www.amazon.com/48-VDC-Kwh-Battery-Pack/dp/B079348MM1 ) (If it's not LiIon, but is lead-acid to be cheaper, you won't want to be using much more than 50% of it before it causes problems). At $1/kWh from the mains, about 8 years of mains electricity to buy it. At $0.25/kWh, 32 years.

cozzyd 6y ago
That has 2500 charge cycles too so...
- jodrellblank 6y ago
  What do you mean? In this scenario of 4 days heating per charge that makes 10k days which is 27 years, and that seems a reasonable sort of lifetime for a product - probably beyond any warranty period it has.
  - cozzyd 6y ago
    Well it limits the time horizon over which it can possibly become cost effective (you have to save more than $28 / charge on average).

cool_dude85 6y ago

Using a big battery in this way under a time of use rate isn't arbitrage, its exactly what the utility company wants you to be doing. That's why they incentivize you to do it with a nice rate. If you spend 70k on a battery and then think you're getting one over on the power company by giving them 100 kWh of storage for the price of the cost difference on their daytime and nighttime rate, the power company is laughing all the way to the bank.

deleted 6y ago
[deleted]
imtringued 6y ago
Although I agree with you, you haven't really explained why it's not arbitrage. If you are not selling back to the grid all you are doing is load shifting. Arbitrage involves buying and selling to reduce spreads.