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Latest insights from SolarPunkLab
The greywater ceiling: why rainwater self-sufficiency gets stuck at 26%
The simulated neighbourhood gets stuck around 24 to 26% water self-sufficiency, no matter how large the rain tank. The ceiling is not in storage but in the greywater split: only the toilet and washing machine may run on rainwater, together 36.8% of household demand. Using more rainwater requires different installations, not bigger tanks.
4 min
The commons leak: what a free rider costs your energy community
In the simulated energy community, a free rider under an open pool draws a net 363 kWh per year more from the shared battery than a regular participant. Pro-rata contribution rules halve that to 204 kWh; under pricing with graduated sanctions, free riders pay for it and adjust. Rules are not paperwork: a load-shifting agreement alone lifts self-consumption from 38.7 to 40.1%.
4 min
The winter wall: why 80% energy self-sufficiency is affordable and 90% is not
For an all-electric neighbourhood of eight households, 80% self-sufficiency costs about 6,100 euros per year, but 90% costs 117,000. That jump is the winter wall: solar output disappears exactly when the heat pumps demand the most, and daily batteries cannot bridge that gap.
4 min
Factor 9: how seasonal storage breaks the winter wall
With seasonal storage, 90% self-sufficiency for the simulated neighbourhood drops from 117,000 to 12,900 euros per year, a factor of 9. But the same installation reaches only 56% instead of 90% without smart control: buying seasonal storage without a control strategy leaves most of the value on the table.
4 min