Off-grid solar for a rural home in Spain: how many panels, which battery, what it costs
A home off the grid lives on its worst month, not its average. In December panels give between a half and a third of what they give in July, and that is when the battery has to hold.
How it is sized
- Daily use: a careful home uses about 5 kWh a day; with a freezer and tools about 7; with pumping for a market garden about 10.
- Panels: daily use divided by what each kWp gives in the worst month, with a margin for inverter and battery losses.
- Battery: enough for 2 cloudy days, lithium, nearly all of it usable.
What it comes to, by climate
| Way of living (daily use) | Sunny south 3.5 kWh/kWp in December | Interior 2.6 kWh/kWp in December | Cloudy north 1.6 kWh/kWp in December |
|---|---|---|---|
| Home only (5 kWh) | 2 kWp · 12 kWh €7,000–11,500 | 2.5 kWp · 12 kWh €8,000–12,500 | 4 kWp · 12 kWh €9,500–15,000 |
| Self-sufficient (7 kWh) | 2.5 kWp · 16 kWh €9,500–15,000 | 3.5 kWp · 16 kWh €10,500–16,500 | 5.5 kWp · 16 kWh €13,000–20,500 |
| Market garden (10 kWh) | 3.5 kWp · 23 kWh €13,500–21,500 | 5 kWp · 23 kWh €15,000–24,000 | 7.5 kWp · 23 kWh €18,000–28,500 |
Installed prices published in Spain (October 2026): off-grid panels, inverter and fitting €1,200–1,800 per kWp; lithium batteries €400–650 per kWh. Ask for three quotes from your real use.
What changes from plot to plot
Winter sun depends on latitude and, a lot, on the hills: a north slope or a closed valley can take hours of December sun away. Each plot's report in the map gives what panels make month by month at that point (PVGIS), and how many hours of direct sun reach it on 21 December with its real horizon.
The paperwork
A licensed installer issues the electrical certificate and registers it with the region. Panels on the ground or on the roof usually need a licence or a notification to the town hall.
Estimates with the same sums as each plot's Dossier. Information, not a design: an installer sizes the system.