Solar & batteries · Buying guide
Balcony solar in Portugal: the 800 W rule, zero-export and which kits make sense
Plug-in “balcony” solar is hugely popular in Germany and the Netherlands. In Portugal it's attractive too — for apartments, rentals and small homes — but the rules are different. Here's how to do it legally and sensibly.
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Key takeaways
- Since 28 August 2026, kits up to 800 W are exempt from prior control only if they never inject into the grid.
- If a kit can export, it needs a prior communication (comunicação prévia) — even below 800 W.
- Zero-export means a controller or battery that matches output to what the home is using right now.
- Savings are modest but real when there's steady daytime base load (fridge, router, pool pump, home office).
The rule in plain English
Under Decree-Law 130/2026, in force since 28 August 2026, the threshold for self-consumption units exempt from any prior control rose from 700 W to 800 W. The catch: the exemption only applies when the installation does not inject surplus into the grid. If it does inject — even a few watts — you need a comunicação prévia. Our UPAC guide explains the wider regime.
How to achieve zero export
- Smart meter + controller: a meter at your main board (for example a Shelly Pro 3EM or a vendor's own meter) tells the micro-inverter or battery how much the house is drawing, and output is throttled to match.
- Balcony battery: systems such as Zendure's or EcoFlow's store midday surplus and release it at a set or measured rate in the evening.
- Undersize deliberately: if your daytime base load never drops below ~300 W, a small array rarely exports — but it isn't a guarantee, so the exemption argument is weaker.
What can you realistically save?
In Portugal an 800 W kit (around 800–1,000 Wp of panels) on a sunny, unshaded balcony or terrace can produce on the order of 1,000–1,300 kWh a year. With zero export you only benefit from what you actually use at the time, so a home with a steady base load captures most of it, while an empty holiday home captures little. At €0.17–0.24 per kWh avoided, a well-used kit saves roughly €150–300 a year.
| Situation | Fit for balcony solar? |
|---|---|
| Apartment, home office, fridge + router + pool/aquarium pump | Good — steady daytime base load |
| Full-time home that already has rooftop solar | Little benefit |
| Holiday home empty most weeks | Poor, unless paired with a battery and remote monitoring |
| Rental where you can't touch the roof | Good — portable, take it with you |
What to look for in a kit
- Inverter output capped at 800 W and EU-certified, with documentation you can show if asked.
- A zero-export / power-limiting mode that works with a meter at your main board — not only a fixed schedule.
- Local control (Home Assistant integration or local API), so it keeps working if the vendor cloud doesn't.
- Panel mounting rated for wind; coastal sites in Portugal get strong gusts.
- Warranty handled in Portugal or the EU, and spare parts availability.
Kits and batteries worth shortlisting
Zendure balcony storage systems
Best for: Zero-export with storage, app + local integrations
Zendure is one of the best-known European balcony-storage brands. Its systems sit between panels and the plug, storing midday surplus and feeding it back at a controlled rate.
- Designed for the plug-in market
- Battery smooths output into the evening
- Adds cost versus a bare kit
- Check the current model's zero-export options for Portugal
EcoFlow power stations and balcony solutions
Best for: Backup power plus balcony solar
EcoFlow's portable power stations double as backup during outages — useful in rural Portugal — and the brand sells balcony solar bundles.
- Portable backup for outages
- Large ecosystem
- Portable stations aren't a substitute for a fixed home battery
Shelly Pro 3EM energy meter
Best for: Measuring house load for zero-export control
A DIN-rail meter that measures what your home draws in real time — the signal many controllers and Home Assistant automations use to throttle a kit. Installation in the consumer unit is a job for an electrician.
- Works locally with Home Assistant
- Single or three-phase
- Must be fitted in the electrical board
Frequently asked questions
Is balcony solar legal in Portugal?
Yes. Up to 800 W it needs no prior control as long as it doesn't inject into the grid; if it can export, a prior communication is required.
Can I just plug it in and let it export?
Not without a prior communication — and you wouldn't be paid for the export without a sale contract anyway.
Will a balcony kit power my house during an outage?
Standard grid-tied micro-inverters switch off when the grid fails. Only systems with a battery and a dedicated backup output keep power available.
Sources
- Novo regime do autoconsumo de energia: o que muda — Doutor Finanças (accessed 29 October 2026)
- Posso vender o excedente dos painéis solares? — Doutor Finanças (accessed 29 October 2026)