Accounting for the battery wear and efficiency
The Sofar EMS's control algorithm, when set to cost optimization, takes into account battery efficiency, as well as a minimum price difference (between less expensive and more expensive moments) that must be present before the Sofar EMS will use the battery. You can use that minimum price difference to factor in battery wear.
You can set the efficiency under the "Devices"→"Change settings" tab under the corresponding battery→"Roundtrip efficiency (%)."
The minimum price difference for using the battery can be set under the "Settings"→"Minimum price difference between peak and off-peak for use of storage (EUR/kWh)". This option is visible if cost optimization is active for storage.
Note
Please note: The control algorithm will only utilize the battery when controlling for cost optimization if the price of the energy with which it is charged is sufficiently lower than the price of the energy at the scheduled time of discharge.
This takes both into account the stated minimum price difference and the efficiency of the battery. After all, the losses when charging/discharging the battery also have a cost.
The price of the charged energy depends on:
- Whether the charged energy comes from its own production (then the selling price of the energy to the grid is used)
- Whether the charged energy comes from the grid (then the purchase price of energy from the grid is used)
- Battery wear cost
- Battery efficiency
Example:
If the purchase price of energy from the grid is 0.20 EUR/kWh at time B, and the battery has an efficiency of 80%, and a minimum price differential of 0.04 EUR/kWh is set, then the battery will only charge at an earlier time A to cover the consumption at that purchase price at time B as soon as the purchase price at the time A of charging is lower than:
0.20 EUR/kWh - 0.20 EUR/kWh*(1-0.80) - 0.04 EUR/kWh = 0.11 EUR/kWh.
Consequences:
This may mean that during periods of long-term stable prices, the battery is hardly ever used. After all, the difference between the minimum and maximum energy price is then potentially rarely greater than the utility cost of the battery.