Alicante gets roughly 3,000 hours of sun a year, and a well-oriented kilowatt of panels produces somewhere around 1,500 to 1,700 kWh annually. Those are genuinely good numbers and they are why solar works here.
They are also not the number that determines your return.
Why generation is the wrong number to focus on
Because the electricity you generate is worth two very different amounts depending on what happens to it.
Electricity you use as you generate it saves you the full price you would otherwise have paid to import it. Electricity you export is compensated at a substantially lower rate. That gap is the single most important figure in any solar calculation, and it means the same array can have very different returns in two houses that generate identically.
The technical term is self-consumption: the proportion of what you generate that you use yourself. A house with high self-consumption does well. A house that exports most of its generation does considerably worse, no matter how much sun the panels see.
What determines self-consumption?
When you use electricity, not how much.
A household that is out all day and does its washing, cooking and television in the evening will export most of what it generates. A household that runs a pool pump, a dishwasher, air conditioning and a car charger between eleven and five will use most of it. Same panels, same roof, same sun, materially different outcome.
This is why we ask for hourly consumption data before sizing anything. Your distributor holds it, you are entitled to it, and it turns the whole conversation from an estimate into a calculation. Anyone quoting a system size and a payback period without having looked at it is guessing, and the guess is usually optimistic.
Why a smaller array is often the better investment
Because of what the extra panels are worth.
Once your array covers what you can absorb during the day, every additional panel produces electricity you cannot use, which means it produces exported surplus. Exported surplus earns the lower rate. So the marginal panel earns considerably less than the first panel did, and the payback period on the system as a whole gets longer as you add capacity beyond your consumption.
There is a further constraint people are often not told about: the compensation mechanism offsets your energy charges rather than paying you. In practice this means exporting far more than you import does not turn into income. Sizing an array to “sell electricity” misunderstands how the arrangement works in Spain.
The practical conclusion is uncomfortable for anyone selling by the panel: for many households the right array is smaller than the one they are being quoted.
The cheapest way to improve your return
Move your consumption into daylight. It costs nothing.
Running the washing machine, the dishwasher, the pool filtration and any car charging in the middle of the day converts exported surplus into self-consumption, and that conversion is worth the full difference between the import price and the compensation rate. On most installations this is a larger improvement than adding panels would be, and it requires changing a timer rather than spending anything.
Does orientation ruin it?
Less than people fear. South produces the most over a year, but east and west arrays lose relatively little annually and can match consumption better.
A west-facing array produces into the late afternoon, which on this coast is exactly when air conditioning demand peaks. In self-consumption terms that timing can be worth more than the extra annual kilowatt-hours a south-facing array would have generated.
What genuinely hurts is shading. Partial shade on one panel affects more of the array than most people expect, and a chimney, an aerial or a taller building nearby matters far more than a few degrees of orientation.
What about batteries?
A battery competes against the compensation rate, not against your full import price, for the portion it stores. That makes the case weaker than it first appears, and it is why we usually suggest installing the array first, living with it for a season, and looking at your actual surplus profile before adding storage.
The exception is where the value is not purely financial: an unreliable supply, or wanting light and a fridge through a cut. Worth knowing there, though, that a standard grid-tied system does not keep working in a power cut on its own — that needs a hybrid inverter and a designated backup circuit, specified deliberately.
The short version
Good sun is not the differentiator here; everyone on this coast has it. What separates a good investment from a mediocre one is how much of your generation you use yourself, and that is a question about your daily routine rather than your roof.
