Off-grid is a technical question with a legal answer. The panels and the battery are the easy part; whether the authority will accept a house that is not connected to water and sewer is the part that decides the project.
Winter yield, not peak rating
A photovoltaic array is sized by the month it performs worst, not by its nameplate. In December, a roof in Denmark or northern Germany produces a small fraction of its July output, while heating demand is at its maximum. That inversion is the whole design problem. Sizing from an annual average produces a system that works beautifully from April to September and leaves you on a generator in January.
Battery storage buys hours, not seasons
Storage bridges a night and smooths a cloudy day. It does not bridge a northern European winter. A realistic off-grid design for year-round occupation in our destination markets combines a well-insulated envelope, a heat pump sized for the actual load, solar for the shoulder seasons, and a defined fallback — rather than an oversized array that still fails in the fourth week of December.
The legal side is usually the binding constraint
In Denmark, wastewater and drinking water are tightly regulated and off-sewer solutions require approval. In Switzerland inside the building zone, a connection is generally expected. In the Netherlands it depends on the function assigned in the omgevingsplan. In Germany many municipalities require a connection to water and sewer wherever residential use is approved. Solar and storage rarely replace servicing entirely; they reduce the running cost of a connected house.
Heating: match the system to the occupancy
A permanently occupied house and a holiday unit that sits on frost protection for five months want different systems. A heat pump is efficient when it runs steadily against a well-insulated envelope; it is a poor answer to a house that is cold and needs to be warm in two hours, six times a year. Underfloor heating levels temperature but responds slowly. Deciding this before production means the emitters, the controls and the insulation are one design instead of three compromises.