How does solar self-consumption work?

Beginner-friendly guide. Indicative figures based on PVGIS Málaga and RD 244/2019. Translation may need a fact-check pass.

Solar panels convert sunlight into electricity you can use directly at home. It’s simpler than it seems — and understanding it helps you make better decisions about your installation. Here’s the complete explanation, with real Málaga data and without unnecessary technical terms.

Step-by-step process

1. Panels generate DC electricity

Photovoltaic solar panels contain silicon cells that generate direct current (DC) when receiving sunlight. In Málaga, with 2,128 kWh/m²/year solar irradiation PVGIS 5.2 · 2026-04-08 (data from PVGIS, European Commission), each kWp installed produces 1,656 kWh/year.

Production per kWp in Málaga

1,656 kWh/kWp/year

Fuente: PVGIS 5.2 · optimal angle 34° · azimuth 2° south

2. Inverter transforms DC to AC

The inverter is the “brain” of the installation. It converts direct current (DC) from panels to alternating current (AC), which is what your appliances and the grid use. Without inverter, panels would be useless for a home.

3. You consume what you produce — in real time

Your home first consumes generated solar electricity. Fridge, washing machine, AC, computers — all run on your own energy while there’s enough sun. If you produce more than you consume, the surplus goes to the next step.

4. Surplus is exported to grid

When you produce more than you consume (typically at noon), surplus electricity is automatically injected to grid through the bidirectional meter. Your retailer compensates you for that surplus by discounting it from your bill.

What is self-consumption ratio?

The self-consumption ratio is the percentage of your solar production you consume directly, without going through grid. It’s the most important indicator to understand how much your installation really saves you.

Configuration	Self-consumption	Explanation
No battery	30-40%	You consume only when producing (sun hours)
With 5 kWh battery	~60%	Store daytime production for evening-night
With 10 kWh battery	~75%	Cover almost the whole night
With 15+ kWh battery	~85%	Maximum independence (marginal performance)

The 30-40% without battery can be improved with smart appliances (wash/dry/charge electric car during sun hours) up to ~50% without adding battery.

How does surplus compensation work?

The Royal Decree 244/2019 regulates the simplified compensation system, applied to virtually all residential installations under 100 kW:

To dive into the different modalities and which to choose, read our self-consumption vs grid feed analysis.

Do I need a battery?

It’s not mandatory. An installation without battery works perfectly and is profitable. The battery improves self-consumption and energy independence, but has significant cost that doesn’t always compensate.

Configuration	Investment 5 kWp	Savings/year	Payback
No battery	€6,000 – €7,500	~€779	~8 years
With 10 kWh battery	€11,000 – €13,000	~€1,100	~11 years

Battery adds ~€320/year savings but costs ~€5,000 more. Battery-only payback: 15 years. We analyze the topic in detail in our battery price guide.

See full detail in our battery price guide.

How many panels do I need based on my bill?

Quick reference based on your current monthly bill amount:

Monthly bill	Recommended system	500W panels	Annual production
€50-80	3 kWp	6 panels	~4,968 kWh
€80-150	5 kWp	10 panels	~8,280 kWh
€150-250	7-8 kWp	14-16 panels	~11,592-13,248 kWh
€250+	10 kWp	20 panels	~16,560 kWh

Maximum 10 kWp for residential self-consumption installations (above changes paperwork). For precise calculation use our calculator with data from your exact municipality.

For an exact calculation with real data from your municipality (not all have the same radiation), check our how many panels guide.

Calculate your specific case

Every home is different. Our solar calculator uses real PVGIS data for your exact municipality (Marbella, Nerja, Torrox, etc., each with slightly different production) and gives you a personalized estimate with scenarios with and without battery, with and without subsidies.

Preguntas frecuentes

Do solar panels work with rain or cloudy weather?

Yes, but with lower performance. On cloudy days they produce approximately 10-25% of a sunny day. Solar production is measured by total annual radiation (in Málaga: 2,128 kWh/m²/year), not by individual sunny days.

What if there's a grid blackout?

By law, standard installations must disconnect automatically when grid drops (to protect operators). To keep electricity during a blackout, you need an inverter with UPS function (backup) and a battery. Not all inverters support it — verify before buying.

How much maintenance does a solar installation need?

Very little. Annual panel cleaning (dust, pollen), visual inspection of wiring and connections every 2-3 years, and inverter replacement at 10-15 years. No moving parts or mechanical wear.

Can I install solar panels if I live in an apartment?

Only if the building adopts collective self-consumption (RD 244/2019) — installation goes on community rooftop and production is shared between neighbors. Requires owners' community agreement. If you live on ground floor with own patio, you can install on your private part.

What happens with the installation when I sell the house?

Installation stays with the property and increases sale value. Studies show 3-8% increase in sale price. Panel warranty (25 years) transfers to new owner.