I need to get my head around a thing and how to do this with NR:
- let's assume I have a fuel-tank / a battery that is able to store/provide a certain amount of energy (kWh) between full (100%) and empty (10%) of its total capacity.
- before I start to draw power from that tank/battery, I want to know the value/cost for each kWh currently stored/ that will be consumed (if I choose to start drawing from that tank/battery at this time)
- the tank/battery however is filled at different times with different amounts of energy, which also has a different price-tag/cost associated with it. Hence the combined/total value of all the Energy chunks of the mixture inside that tank/battery is not constant.
In addition, this is what I know of the parameters:
- net/usable capacity in kWh of the tank/battery between 10% and 100% -> 30kWh
- when charging, I know the Power (W) that is charged, at any given time (actually I am storing these values in an influxDB, too)
- when charging, I know the cost per kWh at a certain time for each source of energy going into the tank/battery
- in my installation I am able to distinguish between loads of different types (heatpumps, EVs, Home, tank/Battery) at any given time.
At home, I have quite a large solar array, a home battery, and 2 heatpumps, as well as 2 electric vehicles.
I do have separate tariffs for my home and the heatpumps/EVs, where the latter tariff is a fixed price and the tariff for home is a dynamic price (tibber) with different hourly rates across the day.
For energy from my solar array, when fed into the grid, I also get a fixed price per kWh, hence when feeding solar energy into the battery, I lose that money (but still saving money overall as the external tariffs will always be more expensive than the money earned from feed-in, even if inefficiency of the energy conversion via the battery is considered).
In general, the tariff for heatpumps/EVs is substantially lower than the tariff for my home.
Because of the nature of the physical installation
- available solar energy will be directly consumed by active loads at that time
- any excess solar energy will be stored in the battery until a target SoC is reached
- any excess solar energy after that will be fed-in to the grid
- when the battery gets charged from the grid, the tariff for home-use (tibber dynamic prices) will be applied.
Because of the price differences in my tariffs I want to decide when it is commercially more feasible to exempt certain loads from being fed by energy from the tank/battery.
Hence I need to have the price-tag of energy stored in my tank/battery at any given time in order to make that decision.
A decision based on SoC and (dynamic) price for charging, which some other people use, is only good for the decision when to charge the tank/battery (lowest price strategy, even with or w/o energy forecasting) and I am planning to combine the two strategies.