If you have solar panels on your villa, spend the winter months here and still wince at the December electricity bill, this is for you. Your panels have not stopped working. In winter, the sun and your consumption simply happen at different times of day, and the Spanish tariff makes that mismatch expensive. A solar battery is designed to close that gap. Below we explain how, who it really helps, and what you should not expect from it.
1.Why your bill goes up in winter, even with solar panels
Since the clocks went back at the end of October, it is dark before six in the evening on the coast of Murcia and the southern Costa Blanca. For a solar system, that changes three things:
- Lower production. Shorter days and a lower sun mean your panels generate noticeably less than in June or July. How much less depends on your roof’s orientation, tilt and shading.
- Higher evening use. Lights go on earlier, cooking, TV, the water heater, and in many villas the heat pump (air-conditioning units on heating mode, or an air-source heating system) running from early evening until bedtime. Spanish villas are built for summer, and many feel cold on winter nights.
- Those are the expensive hours. Almost every Spanish home is on the regulated 2.0TD access tariff. On weekdays, peak periods run from 10:00 to 14:00 and from 18:00 to 22:00, as set out in CNMC Circular 3/2020. Weekends and national holidays are entirely off-peak.
So at midday your panels produce more than the empty house uses and the surplus goes to the grid. At seven in the evening you are buying electricity at peak rates. That is the winter mismatch.
2.Your summer surplus does not pay January’s bill
Many owners from the UK, Belgium or France assume that what they export in summer builds up credit for the winter. Under Spain’s simplified surplus compensation, regulated by Royal Decree 244/2019, it does not work that way. Exported energy is offset on the same bill, and the offset cannot exceed the value of the energy you bought from the grid in that billing period, which is one month at most. Whatever is left over is generally lost. Some suppliers offer their own virtual battery
schemes, each with its own conditions, so read the small print carefully.
On top of that, exported energy is usually valued well below the price you pay to buy it. In winter, every kWh you use yourself is worth more than one you export at midday.
3.How a solar battery helps in winter
The principle is simple. The surplus your panels produce around midday is stored in the battery instead of going to the grid for very little. From 18:00, when the sun has gone and peak hours begin, the house draws on the battery first and only then on the grid.
In practice, that gives you three benefits:
- You make the most of every kWh you produce. Winter production is lower, so losing part of it to the grid hurts more.
- You buy less at peak times. The battery covers part of your evening consumption, which is exactly the expensive slot.
- Backup during power cuts. With a hybrid inverter set up for backup, essential circuits can keep running during a grid outage. In winter, with long dark evenings, many owners value this as much as the savings. Spain’s nationwide blackout in April 2025 made it a very common question.
Depending on your consumption, your system and your tariff, a battery can noticeably reduce what you buy from the grid at peak times. We will not quote a fixed figure, because there isn’t one: it depends on your winter production, your evening use and the battery’s capacity.
4.Who benefits most, and who less
A battery tends to make most sense if:
check You live at the villa all year, or spend the winter here, and your heaviest use is in the evening. check You heat the house with a heat pump and run it after sunset. check Even in winter your panels export at midday because the house is empty while you are out. check You have, or plan to buy, an electric car that you charge in the evening.
It makes less sense if:
close Your system is small and in winter you already use almost everything it produces at midday. There is no surplus to store, so adding panels usually comes first. close The villa is closed all winter. Consumption is minimal and the battery would do little in those months.
If you only spend part of the year here, our guide to solar for holiday homes in Spain covers your situation. For the general, all-year view, see is a solar battery worth it if you already have panels?
5.A typical case in our area
Picture a villa in Pinar de Campoverde or at La Torre Golf whose owners used to come mainly in summer and now spend the winter here. The panels were sized with July in mind. At midday in December there is still some surplus, because nobody is home. But at seven in the evening the heat pump, the oven and the TV all come on, and all of that is bought from the grid at peak rates.
With a battery, the midday surplus stays in the house and covers part of the evening. That is what we did in the battery upgrade in Pinar de Campoverde we described earlier: no need to start again, just build on the existing system.
6.Monitoring from home when you go back
Most battery systems come with an app that shows production, consumption, battery level and grid use in real time. If you spend part of the winter back in the UK or elsewhere, you can still check how the villa is doing, spot an unusual consumption pattern, or confirm that backup is working after a storm. We set it up on your phone at handover and explain it in English.
7.What to check before adding a battery
A battery should not be chosen from a catalogue. A licensed installer should go through these points with you:
- Your real hourly consumption. Your distribution company’s consumption data shows how much of your use falls in the evening and how much surplus you have at midday, including in winter. We can request and read it for you.
- Your current inverter. If it is not a hybrid model, a battery may need an extra unit or a new inverter. We confirm this at the survey.
- The right capacity. Bigger is not always better: a battery that never fills up in winter is oversized for you.
- Where it goes. Garage, plant room or a wall out of direct sun, with ventilation and the right protection devices.
- Your tariff. Some inverters can charge the battery from the grid during off-peak hours. Whether that pays off depends on your tariff and on how your system is registered, so we assess it case by case.
Anything involving the consumer unit, connections or inverter settings is a job for a professional: it means high-voltage direct current and your main electrical panel.
8.Frequently asked questions
8.1.Do solar panels produce anything in winter in Murcia and the Costa Blanca?
Yes. There is plenty of winter sunshine in the Region of Murcia and the Vega Baja, but fewer hours and a lower sun, so production is clearly lower than in summer. That is why getting the most out of every kWh matters so much in winter.
8.2.Will a battery bring my winter bill to zero?
No. It reduces what you buy from the grid, especially at peak times, but you will still have a bill: the fixed power charge and part of your consumption, particularly on cloudy days or when production is not enough to fill the battery.
8.3.Can I add a battery as a non-resident?
Yes. Residency is not a requirement to install or legalise a battery on your self-consumption system. We handle the technical side and the paperwork; you approve the project and sign the authorisations.
8.4.Can I install a battery now, in the middle of winter?
Yes, it can be installed at any time of year. We just need to check first that your inverter is compatible or can be adapted.
8.5.Are there grants for batteries at the moment?
Calls for grants open and close frequently, so do not count on one until it is confirmed. At present, the most common benefits are tax deductions and local tax discounts, which depend on your tax situation and municipality. Our guide to solar grants and deductions in Spain covers the details; always check the official source and, for tax matters, your adviser.
Tariff and regulatory information was checked against official sources at the time of publication. Rules and tariffs change: always check your specific case.
9.Find out if a battery pays off for your villa this winter
The reliable way to know is to look at your real consumption, hour by hour, and see how much could move from peak hours to your own battery. We do it free and with no obligation, in English, and if a battery does not make sense for you, we will tell you. If you do not have panels yet, start with our solar panel installers page.