Mejor Tarifa Eléctrica tras Instalar Placas Solares en España

Respuesta Rápida

How to analyze and compare electricity contracts after installing solar panels. La configuración óptima depende de su consumo real, la orientación del tejado, las necesidades de batería y la elección de la tarifa de exportación adecuada.

There is no single best tariff

The Spanish electricity market features hundreds of commercial suppliers (comercializadoras), each offering distinct tariffs for solar customers. The optimal tariff for your property depends entirely on your consumption profile.

For instance, a home with a large physical battery that imports almost zero energy will prioritize low standing power charges (potencia) and a virtual battery with no monthly maintenance fees. Conversely, a high-consumption villa without a battery will prioritize the lowest possible night-time import rate (price/kWh).

Comparison diagram showing the difference between a physical solar battery and a virtual battery tariff

What to compare in post-solar tariffs

When evaluating solar energy contracts, you must analyze the complete pricing structure:

Import Price (P1, P2, P3): The price you pay for energy drawn from the grid. Time-of-use tariffs have different rates for peak (punta), flat (llano), and off-peak (valle) hours.
Export Compensation Rate: The rate paid for surplus solar energy fed back into the grid.
Virtual Battery Option: Whether the supplier allows surplus credits to accumulate to offset fixed charges or apply to a second property.
Fixed Daily Power Fee (Potencia): The cost per kW of contracted power capacity. This represents a significant portion of Spanish electricity bills.

Anonymised Spanish electricity bill mockup showing solar export compensation and tariff charges

Why import prices still matter after installing solar

Unless your property is completely off-grid with massive battery storage, you will continue to import electricity. Most residential solar production occurs between 10:00 and 16:00, whereas peak household usage often occurs in the evenings (lighting, cooking, entertainment) and overnight (air conditioning, heating, pool filtration).

Choosing a tariff with a slightly higher export rate but a penalizing import rate is a common mistake. A low import rate is critical for keeping bills low during the winter and cloudy periods.

Reviewing your contracted power (potencia contratada)

Contracted power represents the maximum electrical capacity your home can draw from the grid simultaneously before the main breaker trips. In Spain, you are billed a fixed daily rate per kW of contracted capacity.

Installing solar panels does not automatically mean you can reduce your contracted power, because you still need full capacity at night. However, if your solar system includes peak-shaving capabilities (where the battery feeds power to meet household spikes), you may be able to safely reduce your contracted power by 1 to 2 kW, saving up to €100 per year in fixed charges.

Want a full tariff comparison?

If you already have solar installed, the best tariff depends on your import prices, export compensation, battery setup, virtual battery terms and actual usage pattern. Costa Solar Guide can explain what to look for, while weSwitchSpain can help with a full bill review and supplier comparison.

Costa Solar Guide and weSwitchSpain are separate services focused on related parts of the solar and electricity decision.

Preguntas Frecuentes

Why can the wrong electricity tariff reduce my solar savings?

The wrong tariff can cancel out your solar savings if it charges high import rates during the evening when your panels are not producing. Many solar owners focus only on getting a high export rate (e.g. €0.10/kWh) and ignore the fact that the supplier charges €0.28/kWh for grid imports at night. Balancing import prices, export compensation, and standing charges is critical for minimizing your total bill. We recommend reviewing your hourly import patterns to ensure your tariff aligns with your real usage.

Should I choose a low import price or a high export price?

You should prioritize a low import price unless your system is heavily oversized and generates massive daytime surpluses. Most homes still import a significant portion of their electricity during the evening and night for lighting, cooling, or pool filtration. A tariff with a slightly lower export rate but a much cheaper import rate will usually save more money overall. A practical next step is calculating your self-consumption ratio to see how much energy you import.

Do I need a special solar tariff?

Yes, you must switch to a tariff that supports export compensation (compensación de excedentes) to receive credits for the energy you feed back into the grid. Standard tariffs do not offer any credit for surplus generation. However, you do not need to stay with your installer's recommended supplier; you can choose any commercial supplier that offers competitive solar terms. We recommend performing a tariff comparison once your system's CIE registration is complete.

Is a virtual battery always better?

A virtual battery tariff is not always better, as some plans charge monthly management fees or impose higher import rates that negate the benefits of the cloud storage. Virtual batteries are highly beneficial if you have a large system that generates significant surpluses, or if you own a holiday home. If your system is small and you consume most of your solar energy directly, a standard export tariff may be cheaper. We recommend calculating your expected monthly export volume first.

How does a physical battery change tariff choice?

A physical battery allows you to choose a tariff with higher daytime import rates but very low fixed charges (potencia), because your battery will cover your household demand during peak hours. You can also target tariffs that offer extremely cheap night-time import rates to charge the battery from the grid during winter. Without a battery, you must prioritize low daytime and evening import rates. A practical next step is checking whether your inverter supports grid charging configuration.

Should I reduce contracted power after solar?

You should only reduce your contracted power if you are confident that your peak night-time demand will not exceed the lower limit, as solar panels do not assist with power demands after sunset. However, if your system includes a physical battery with peak-shaving capabilities, you can safely lower your contracted capacity by 1 to 2 kW, saving up to €100 annually in standing charges. We recommend monitoring your maximum power demand (maxímetro) via your distributor's portal before requesting a change.

How often should I review my tariff after solar?

You should review your electricity tariff at least once a year, as energy suppliers in Spain frequently adjust their rates, export terms, and virtual battery fees. A tariff that was highly competitive last summer may now be significantly more expensive. Doing a regular bill check ensures you are always on the optimal plan. A sensible next step is to upload a recent summer and winter bill for a free tariff comparison.

Should I choose a fixed or indexed solar export tariff?

If you have a high export volume during the day (e.g. no battery and empty house), a fixed export rate is usually safer. Indexed export rates can fall close to zero during sunny afternoon hours when solar production across Spain peaks.

Can virtual battery credits be used to pay fixed charges?

Yes, many modern virtual battery plans (such as those from Octopus or Helios) allow excess credits to reduce the entire bill—including standing charges, taxes, and meter rents—to €0.

How do I switch suppliers after installing solar in Spain?

Switching suppliers is straightforward. You only need a recent electricity bill containing your CUPS number and your bank details. The new supplier will request the switch directly from the distributor; there is no interruption to your power supply.

Best Electricity Tariffs After Solar