For many houses in Spain, yes. But “worth it” depends on your house, not on the country’s sunshine, and a general figure would not tell you much. This guide shows how the sum works, so you can check any estimate you are given, ours included.
The four numbers that decide it
1. Production: how many kWh the panels make in a year. As an estimate from EU PVGIS data for a roof near Alicante, a system produces roughly 1,550 kWh per kWp a year when it faces south at a good angle, and roughly 1,250 to 1,300 when it faces east or west. 2. Self-consumption: how much of that you use in the house as it is produced. This depends on when you use power. 3. What that power is worth: the price per kWh of the energy you no longer buy, from your own bill. 4. What exported power earns: the rest goes to the grid and is credited on your bill, at a lower value. See selling excess solar electricity in Spain.
The sum
Yearly value = (kWh used in the house × your energy price per kWh) + (kWh exported × the credit per kWh)
Simple payback in years = price of the system ÷ yearly value
Both prices come from your own bill and contract. The energy price is the part of the bill charged per kWh, not the total divided by the kWh; fixed charges do not go down with solar. Can solar panels eliminate your electricity bill explains which parts of the bill change.
A worked example in kWh
This example shows the sum in energy. It is not a figure for your house.
- A 4 kWp system on a south-west roof. At 1,500 kWh per kWp that is about 6,000 kWh a year.
- The household uses about 40 % of that as it is produced: 2,400 kWh.
- The other 3,600 kWh are exported.
- Yearly value = 2,400 × your energy price + 3,600 × your export credit.
Now change one thing. If the same household moves the pool pump and the washing to midday, self-consumption might rise to 55 %: 3,300 kWh used and 2,700 exported. Because used power is worth more than exported power, the yearly value goes up without adding a single panel. That is why self-consumption matters more than system size.
What moves the result
- More daytime use makes solar worth more: air conditioning, a pool pump, working from home, an electric car charged in the day.
- A larger system adds production, but mostly exports if your daytime use does not grow with it.
- The export credit depends on your contract and the market. It is usually lower than the price you pay.
- Energy prices change. If they rise, each kWh you produce and use is worth more; if they fall, less.
- A battery can raise self-consumption, but costs money itself; see do you need a solar battery.
- Upkeep: little on the panels, but an inverter may need replacing within the life of the panels. Allow for it.
What we put on paper
When we give you an estimate, it shows the production figure for your roof, the self-consumption share we assumed and why, the prices we used and where they came from, and the result as a range rather than one number. Estimates are estimates; your actual savings depend on your use and on prices we do not control.
When it is not worth it
Some houses are better off without panels, or with fewer than they think. When are solar panels not worth it covers those cases.
Next step
For what a system costs, read how much solar panels cost in Spain. For how we install across the region, see solar panels in Spain. If you want the sum done for your house, ask for a quote and send a year of bills.
