Off-Grid Solar Systems on Mallorca: Planning a System with Battery Storage
Sandor Farkas
Mallorca expert and author
Anyone who buys a finca without an existing electricity connection - or builds in a remote location - quickly faces a choice: apply for a grid connection or go off-grid with solar? On Mallorca a new grid connection can take years and cost tens of thousands of euros if the cables are not already there. An off-grid solar system with battery storage is in many cases not only the faster option but also the more affordable one.
At a glance
An off-grid solar system runs entirely without a grid connection. You need PV panels, an MPPT charge controller, a battery bank, and an inverter. Sizing depends on your daily consumption and the weakest month for sunlight. Costs for a practical system in 2026 range from EUR 10,000 to EUR 25,000. Public grants generally do not apply to off-grid systems.
Off-Grid or Grid-Tied - What Is the Difference?
A grid-tied photovoltaic system is connected to the electricity network. Surplus power flows into the grid; when you need more than you produce, you draw from the grid. This requires an existing household connection.
An off-grid system (Spanish: sistema aislado de la red) is completely self-sufficient. No grid connection, no feed-in, no standing charge. Everything you use has to be produced and stored by the system itself. That means more work at the planning stage - but genuine independence.
There are also hybrid systems, which combine a grid connection with battery storage so you can draw from the battery during outages or when tariffs are high. That is interesting for fincas with an existing connection, but it is not what this article is about.
The Four Core Components of an Off-Grid System
Every working off-grid installation consists of the same building blocks:
- PV panels: The panels generate direct current from sunlight. For a household, 4 to 12 kWp is typically enough depending on consumption.
- MPPT charge controller: This manages the charging process between panels and batteries and protects the battery bank from overcharging. MPPT controllers (Maximum Power Point Tracking) are significantly more efficient than older PWM types.
- Battery bank: The battery bridges nights and cloudy days. Lithium iron phosphate batteries (LiFePO4) are the first choice: long-lasting (over 3,000 cycles), maintenance-free, and relatively light. AGM lead-gel batteries are cheaper to buy but wear out much sooner.
- Inverter: The inverter converts the DC power from the batteries into standard household AC power (230 V, 50 Hz). Off-grid installations use pure sine wave inverters with a built-in charger function (so-called inverter-chargers), which can also connect an optional backup generator.
Tip: Plan for a Generator Backup
Even a well-sized off-grid system can struggle in winter. Build in a generator inlet from the start. Newer inverter-chargers from Victron or SMA support automatic generator switching.
How to Size the System Correctly
The most common mistake with off-grid systems is getting the sizing wrong. Too small and the system runs short in winter. Too large and you overspend on components.
Sizing follows a simple process:
Calculate your daily consumption
List all appliances with their wattage and daily hours of use. Fridge (80 W, 24 h), lighting (50 W, 6 h), water pump (750 W, 1 h), and so on. Add everything up to a daily kWh figure. A typical four-person household uses 5 to 10 kWh per day.
Identify your worst month
On Mallorca, global solar irradiance drops to roughly 2.5 to 3 peak sun hours per day in December and January. Size the system for this figure, not the annual average of around 5 hours.
Calculate PV capacity
Formula: (daily consumption in kWh / peak sun hours) x 1.3 loss factor = required kWp. At 8 kWh consumption and 2.5 peak sun hours, that is roughly 4.2 kWp, rounded up to 5 kWp.
Determine battery capacity
Plan for 2 to 3 days of autonomy. At 8 kWh daily consumption and 2 days, you need 16 kWh of usable capacity. With LiFePO4 batteries you can use 80 percent of nominal capacity, so around 20 kWh installed.
What an Off-Grid System Costs on Mallorca in 2026
Prices for off-grid systems have come down in recent years, but remain higher on the Balearic Islands than on the Spanish mainland because of installation and logistics costs.
| Posten | Kosten | Dauer |
|---|---|---|
| Small system (3 kWp, 10 kWh LiFePO4) | EUR 9,000 - 13,000 | one-off |
| Medium system (5-6 kWp, 15-20 kWh LiFePO4) | EUR 15,000 - 22,000 | one-off |
| Large system (8-12 kWp, 25-40 kWh LiFePO4) | EUR 25,000 - 40,000 | one-off |
| Optional backup generator (5-8 kVA) | EUR 1,500 - 3,500 | one-off |
| Maintenance and monitoring (annual) | EUR 300 - 800 | per year |
Prices include installation, cabling, switchgear, and commissioning. Materials alone account for roughly 60 to 65 percent of the total. Get at least three quotes from local installers. Good starting points are our service provider directory and the annual Genera trade fair in Madrid.
Warning: Avoid Cheap Batteries
The battery bank makes up 40 to 50 percent of system costs. This is not the place to cut corners. Cheap lithium batteries without proper certification (UL, CE, IEC 62619) are a fire risk. Stick to established manufacturers such as Pylontech, BYD, CATL, or Victron.
Grants for Off-Grid Systems - What Actually Applies
There is a common misconception here: Spanish and Balearic grant programmes for photovoltaics are almost exclusively aimed at grid-tied self-consumption (autoconsumo) installations. These include programmes from IDAE, the GOIB (Govern de les Illes Balears), and municipal grants under the Next Generation EU framework.
For pure off-grid systems without a grid connection, these grants generally do not apply. There are two exceptions worth checking:
- Some municipalities on Mallorca explicitly support self-sufficient energy supply in remote locations, sometimes through rural infrastructure funding.
- The Balearic tax authority (ATIB) allows a tax reduction on the regional income tax (IRPF tramo autonomico) for investments in renewable energy. This does apply to off-grid systems.
Get advice from a local tax advisor before writing off the investment. Rules change every year. More on the tax situation on Mallorca is in the guide to running costs on Mallorca.
What to Clarify Before Installation
Before signing a contract, go through these points with your installer:
- Does a planning permission or installer notification need to be submitted to the local council? For off-grid systems on private land, rules vary by municipality.
- What are the warranty terms for batteries and inverter? Lithium batteries typically carry a 10-year manufacturer warranty; inverters usually 5 years.
- Will a monitoring system be installed so you can check the system remotely? Victron VRM and SMA Sunny Portal are both widely used and free.
- Is the system designed for future expansion? An inverter with insufficient input capacity is hard to upgrade later.
If you are renting the finca before buying, check in the rental contract who owns any installed system. More on finca rentals is in the guide to long-term finca rental on Mallorca.
Conclusion
An off-grid solar system on Mallorca is the most practical solution for fincas without a grid connection. The key is careful sizing: know your daily consumption, design for the winter months, and you will be fine year-round. Public grants are limited, but the investment pays off in the long run through avoided grid connection costs and permanently low running costs. Get at least three local quotes, compare component manufacturers carefully, and build in a backup generator from the start.