Grid-tied, no battery
The simplest and usually the quickest payback. Panels cover daytime use and the grid covers the night. It works best if you shift loads such as washing, dishwashers and water heating into the middle of the day.
Off-grid living, Iberia edition
Off-grid and low-energy living in sunny Europe, by the numbers
Sunward is about running a home on sunshine, rain and good design in Portugal and Spain. We start with measured figures, show our working, and say plainly where the sun stops being enough. No hype, no miracle kits, just the maths of energy independence.
1,592 kWh
Yearly output of 1 kWp of panels near Lisbon
~2,800 h
Sunshine hours a year in Lisbon; Faro tops 3,000
3x
December output in Lisbon compared with Berlin, per kWp
23%
VAT on solar in Portugal since the 6% rate ended in mid-2025
Output figures: European Commission PVGIS model, south-facing at optimal tilt, 14% system losses. Sunshine hours: long-term climate averages.
01
Solar hours in Iberia: what the sun actually gives you
Sunshine hours make good postcards, but the number that sizes a system is energy per installed kilowatt. Run the European Commission's PVGIS model for a south-facing array near Lisbon at its best tilt (about 33 degrees) and 1 kWp of panels produces about 1,592 kWh a year. Near Seville the same array makes about 1,657 kWh. In Berlin it is about 1,062 kWh.
The annual total hides the part that matters for independence. Near Lisbon, July delivers about 172 kWh per kWp and December about 92 kWh. Winter is a little over half of summer. That is a gift compared with northern Europe, where December can fall to a quarter of July or less, but it still means an array sized for summer will run short in winter.
Two practical rules follow. Size an off-grid array for December, not for the average month. And treat the summer surplus as a resource to plan for, whether that is running the pool pump at noon, heating water, or accepting that some sunshine goes unused.
02
Solar sizing estimator
Enter how much electricity you use in a day and pick a mode. The estimator uses the PVGIS figures above, so it assumes an unshaded, south-facing array at a good tilt. It is a rough starting point for a conversation with an installer, not a design.
03
Home solar and batteries without the sales pitch
Most people asking about off-grid living in Portugal really want one of three things: a smaller bill, resilience during outages, or no grid connection at all. They lead to very different systems, and the cheapest route to the first is rarely the right route to the third.
Grid-tied with a battery
A battery moves midday surplus into the evening. Because surplus sells for far less than grid power costs in Portugal, storing it can make sense. Check that the inverter can keep chosen circuits running in a power cut: many cannot without an extra switch.
Fully off-grid
Sized for the worst week of winter, with a bigger array, more storage and usually a backup source. Lithium iron phosphate (LFP) batteries are now the common choice for homes. Read warranty terms on both years and total energy throughput.
04
Self-consumption rules in Portugal, and how Spain differs
Portugal regulates home solar under its self-consumption regime, Decree-Law 15/2022, where a home installation is known as a UPAC. The paperwork depends mainly on installed power and on whether you export. An amendment that took effect on 28 August 2026 raised the smallest threshold, so older guides may quote 700 W.
| Installed power | What applies |
|---|---|
| up to 800 W | No prior control, provided nothing is exported to the grid. |
| 800 W to 30 kW | A prior communication to DGEG, the energy directorate, through its online portal. Most homes fall here. |
| above 30 kW | Prior registration and an operating certificate. |
| any exporting system | Needs a contract with a buyer for the surplus, and a smart meter. |
Portugal
No net metering
Surplus is sold, not banked. Buyers and aggregators usually pay a price linked to the Iberian wholesale market, minus a margin. It is always well below the price you pay per kWh, which is why consuming your own power is worth more than selling it.
Spain
Simplified compensation
Under Royal Decree 244/2019, installations up to 100 kW can have exported energy valued and discounted from the bill, capped at the cost of the energy consumed in that period. It is not full net metering either, but it is simpler for households.
tax
VAT is back at 23%
Portugal's reduced 6% VAT on supplying and installing panels covered work invoiced up to 30 June 2025. Parliament has since recommended restoring it, so check the rate on the day you sign.
05
Rainwater harvesting, greywater and composting toilets
Water is the half of off-grid living that solar blogs skip. The arithmetic is simple: 1 mm of rain on 1 m² of roof is 1 litre. Lisbon gets roughly 700 to 800 mm a year and the Algarve coast about 500 mm. A 100 m² roof catching 80% of 600 mm yields about 48,000 litres a year.
The catch is timing. Almost all of it falls between October and April, and the summer is long and dry. Rainwater harvesting in Portugal is therefore a storage problem more than a collection problem: tank size decides how far into summer you get.
rain
Collect, filter, store
Use a first-flush diverter, keep tanks dark and cool, and decide early whether the water is for garden and toilets only or treated for drinking. Drinking use needs proper filtration, disinfection and regular testing.
greywater
Reuse shower and sink water
Greywater can water trees and ornamental beds. Use plant-friendly soaps, send it to the soil quickly rather than storing it, and keep it away from vegetables you eat raw.
sanitation
Composting toilets
They save the most water of anything here and work well when managed properly. Acceptance by councils varies, so ask your câmara municipal what it will approve before you build, and get the answer in writing.
06
Wood stoves, heat pumps and staying warm on little energy
Sunny does not mean warm indoors. Many older Portuguese houses have thick stone walls, single glazing and no central heating, and they feel colder in January than a well-insulated house in Germany. The cheapest kilowatt-hour is the one you never need, so insulation, draught-proofing and good windows come first.
After that, a heat pump is usually the most efficient electric option: in a mild Iberian winter it typically delivers several units of heat for each unit of electricity. The problem for off-grid homes is timing. Heating demand peaks on the dullest days, exactly when solar output is lowest. That is why many off-grid households pair a modest heat pump with a wood stove, ideally one with a back boiler or a thermal mass that stores heat. Burn only well-seasoned wood: wet logs waste heat and soot the flue.
07
What off-grid really costs
Prices move quickly, so here is the shape of the bill rather than a figure that will soon be wrong. Get at least three itemised quotes and compare them line by line against this list.
upfront
The hardware
Panels, mounting, inverter or charger, battery bank, cabling, protection and installation. For off-grid homes the battery is usually the largest single item, and it grows fast with every extra day of autonomy.
backup
The last ten percent
Covering the final few winter days costs far more than the first ninety percent of the year. A small generator or a wood stove is often cheaper than doubling the battery.
over time
Replacement and upkeep
Panels last decades, but inverters and batteries have shorter lives. Budget for replacing them at least once over the life of the house, plus pumps, filters and tank maintenance.
hidden
Your time and habits
Off-grid homes run best when people watch the weather and shift loads. That is a real cost for some households and a pleasure for others. Be honest about which you are.
08
Frequently asked questions
How much electricity does a solar panel produce in Portugal?
The European Commission's PVGIS model puts a well-placed 1 kWp array near Lisbon at about 1,590 kWh a year, after typical system losses. That is roughly 5.5 kWh per day in July and about 3 kWh per day in December. Shading, orientation and tilt can cut this considerably.
Do I need permission to install solar panels on my house in Portugal?
Under the self-consumption regime, very small systems that do not export to the grid are exempt from prior control (the limit rose from 700 W to 800 W on 28 August 2026). Systems above that and up to 30 kW need a prior communication to the energy directorate, DGEG, and larger systems need registration. Planning rules, listed buildings and condominium rules can add further steps, so check with your installer and the local council.
Is there net metering in Portugal?
Not in the classic sense. Surplus solar energy can be sold to a buyer or aggregator under a contract, usually at a price linked to the Iberian wholesale market and well below what you pay per kWh. Spain works differently: installations up to 100 kW can use simplified compensation, where exported energy is discounted from the bill.
Can you live fully off-grid in Portugal or Spain?
Yes, and the sun makes it easier than in northern Europe, but winter is the design problem. December output near Lisbon is a little over half of July's, and cloudy spells of several days happen. Most off-grid homes combine a generously sized array, enough battery for a day or two, low-energy appliances, and a backup such as a generator or wood heating.
Are composting toilets legal in Portugal?
Rules on on-site sanitation are applied locally, and acceptance of composting toilets varies. Before you build, ask the municipal council (câmara municipal) what it will approve for your property, and get the answer in writing.
What VAT applies to solar panels in Portugal?
The reduced 6% VAT rate on supplying and installing solar panels applied to work invoiced up to 30 June 2025. After that the standard 23% rate applies. Consumer and environmental groups have asked for the reduced rate to return, so check the current position before you sign a quote.
About Sunward
[About the editors: to be written]
Rules and prices change. Everything here is general information, not legal, tax or engineering advice. Check current regulations with DGEG in Portugal or your regional authority in Spain, and have any installation designed and signed off by a qualified professional.