4 ms·

Currently, it is cheaper though to "sell" the electricity in summer and "buy" it back in winter (even if it is at 10x the price I sold it for). Compared to priv

Currently, it is cheaper though to "sell" the electricity in summer and "buy" it back in winter (even if it is at 10x the price I sold it for). Compared to private long term storage solutions. Most long term electricity storage solutions will yield electricity at prices above 80c/kWh here (even lithium ion is currently around 50 to 70c, if you calculate 10,000 hrs average lifetime of house batteries). And you cannot use lithium ion for long term storage, you would need H2, or heat storage solutions.

choeger 4y ago
Sand is heat storage, not electricity storage. Storing heat can be much simpler and much more economical (considering that heat is the majority of your energy consumption).
guerby 4y ago
Current consumer friendly rack battery LFP prices are at around 400 EUR/kWh, here an example of a 5.12 kWh for 2100 EUR: https://www.europe.sokbattery.com/product-page/sok-battery-100ah-48v-server-rack-battery https://www.europe.sokbattery.com/product-page/sok-battery-1... These are rated for 6000 cycles to 80% degration, so if we take an average of 90% assuming linear degration we will be able to output 6000 by 0.9 so 5400 kWh for each kWh of battery capacity before the battery reaches 80% of its original capacity. 400 EUR divided by 5400 is 0.074 EUR per kWh out the the battery, an order of magnitude lower than the 0.80 EUR per kWh you quoted. These have low self discharge but capacity prices (price per kWh stored in the battery) are way too high to do seasonal storage. Note: if you DIY the battery it's half the price: 150-200 EUR/kWh at the cell level currently.
- Epa095 4y ago
  Your calculations are interesting for day to day peak shaving, but as you noted yourself, these batteries are way to expensive for seasonal storage. Depending on the insulation on your house, one of those would maybe contain enough power for 0.3-1 hour of power-use in the winter.

choeger 4y ago

Sand is heat storage, not electricity storage. Storing heat can be much simpler and much more economical (considering that heat is the majority of your energy consumption).

guerby 4y ago

Current consumer friendly rack battery LFP prices are at around 400 EUR/kWh, here an example of a 5.12 kWh for 2100 EUR: https://www.europe.sokbattery.com/product-page/sok-battery-100ah-48v-server-rack-battery https://www.europe.sokbattery.com/product-page/sok-battery-1... These are rated for 6000 cycles to 80% degration, so if we take an average of 90% assuming linear degration we will be able to output 6000 by 0.9 so 5400 kWh for each kWh of battery capacity before the battery reaches 80% of its original capacity. 400 EUR divided by 5400 is 0.074 EUR per kWh out the the battery, an order of magnitude lower than the 0.80 EUR per kWh you quoted. These have low self discharge but capacity prices (price per kWh stored in the battery) are way too high to do seasonal storage. Note: if you DIY the battery it's half the price: 150-200 EUR/kWh at the cell level currently.

Epa095 4y ago
Your calculations are interesting for day to day peak shaving, but as you noted yourself, these batteries are way to expensive for seasonal storage. Depending on the insulation on your house, one of those would maybe contain enough power for 0.3-1 hour of power-use in the winter.