My summertime excess power is in the range of 100 to 400 W, and my grid provider tariff does not reimburse. A dedicated storage battery solution is in my setting (700 W peak) economically not sound.
I measure my grid return power with 10 sec time resolution, with an accuracy of up to 1 W. Therefore, I was looking for simple solution involving heating and battery loading:
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Use dishwasher and washer preferably at peak excess periods. A wall mounted display in the kitchen allows an assesment:
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Install automated switches that turn on if excess thresholds are met:
• USB chargers for tablets and cell phone batteries
• Notebook chargers
• Electrical devices with a fitting power consumption, like Slow Cookers (100 or 200W), or Heating Blankets ( ca. 100W).
The slow cooker is used to prepare food or heat 1-3 l of household water and turned out to be very helpful. The following screenshot shows the slow cooker approach:
Battery loading can often be completed during excess times. In addition, the automations look for low battery levels to maintain an operational battery level.
Assessment: A week in July: Considering solar energy, backflow to the grid is 20%, while 80% is used locally.
Further candidates are freezers, which could be set to cool down below minimum temperature in advance (not implemented).
Fortunatly where I am we have 1:1 net metering so this is not a worry for me yet. Eventually when I have build up a bank of power (in form of credit on bill) I may look at doing something similar to use up the excess.
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