Does solar work during a power outage in Ukraine? On-grid, hybrid and off-grid systems explained

Short answer: a standard grid-tied solar system without a battery does not work during a power outage — its inverter switches off automatically, even in full sun. Only a hybrid system with a battery (or a fully off-grid one) keeps the lights on, and a generator or a portable power station can add to it or stand in for it. Below we explain why, and how to choose a setup for the outages you actually get. Facts checked as of October 2026.

Why does a grid-tied solar system shut down in a blackout?

A grid-tied (on-grid) inverter runs in step with the grid, matching its voltage and frequency. When the voltage disappears, the inverter has to disconnect quickly and stop pushing current out. This is called anti-islanding protection.

The reason is safety. If a solar system kept feeding a line that was switched off for repairs, the wires could carry voltage nobody expects. So:

• in Ukraine, clause 4.12.2 of the Distribution System Code requires technical means or inverter settings that automatically disconnect a generating unit from the grid "in case of a sudden loss of voltage" and make it impossible to energise a grid that has no voltage;
• for systems that are not allowed to export, the same clause requires devices that stop any power going into the grid (a smart meter, a generation limiter and the like);
• the international standard IEC 62116 describes how anti-islanding protection in grid-connected PV inverters is tested.

The upshot: panels on the roof do not give you power in an outage on their own. You need an inverter that can separate the house from the grid and run it from a battery or directly from the sun.

On-grid, hybrid or off-grid: what is the difference?

On-grid is the cheapest way to cut your bills, but it does nothing for outages.

Hybrid combines both. While the grid is up, it powers the house from the sun, charges the battery and draws the rest from the grid. When the grid goes down, the hybrid inverter disconnects from it (the same anti-islanding rule) and keeps feeding its backup output from the battery and the panels. The sun recharges the battery during the day, so on a sunny day an outage can pass almost unnoticed.

Off-grid is not connected to the grid at all. It makes sense for a country house or a building with no connection, but it needs a larger battery or a generator for cloudy days.

Some hybrid inverters can also run without a battery, powering appliances straight from the panels while the sun shines. Output then rises and falls with every cloud, so it is no substitute for a battery — check what your model can do in its datasheet.

What do you need to keep the lights on during outages?

1. A hybrid inverter big enough for everything that runs at the same time, and for the start-up surge of motors (fridge, pump).
2. A battery, usually lithium iron phosphate (LiFePO4). Its capacity in kWh decides how many hours the house lasts.
3. A backup output (EPS / backup / load) and a separate backup circuit in the consumer unit. It carries the essentials: fridge, boiler and circulation pump, router, lights, sockets for laptops. Water heaters, ovens and air conditioners usually stay on the grid circuit so they do not drain the battery in an hour.
4. Protection and switching: breakers, an RCD and, if needed, a bypass switch for servicing the inverter.
5. Notifying the grid operator. Ukraine's Distribution System Code provides for a written notice about installing a generating unit (clause 4.12.3, annex 11) and an energy storage unit (clause 4.13.3, annex 12). Check the exact procedure with your local operator.

Before buying, look at the switchover time the manufacturer states: it decides whether a desktop computer or a gas boiler "notices" the outage.

How long will a battery last? A worked example

Take a typical house and run it through SolarPlan's model (which allows for the part of the battery that is not used and for conversion losses).

What we want to keep running (typical values from SolarPlan's model):

A fridge does not run all the time, so the model puts the average load of "fridge + router + lights + laptop" at about 0.4 kW. Hours from a full battery, with no solar top-up:

So a 10 kWh battery carries the essentials through the night and into the next day, but with a 2 kW electric hob or heater it lasts only a few hours. Solar panels extend this during the day — noticeably less on grey winter days.

What it costs: in SolarPlan's price index, a 10 kW system with a 10 kWh battery comes to roughly UAH 344,100–449,700, and the same system without a battery to UAH 198,900–259,900 (SolarPlan model, October 2026; real quotes will differ). See the 10 kW hybrid system page and the solar price index.

How do you combine solar with a generator?

A generator complements a hybrid system when outages are long and sun is scarce. Two common setups:

• Generator into the inverter. Many hybrid inverters have a generator input (or accept one on the grid input): the inverter powers the house and charges the battery from the generator, which can then be switched off. The inverter's manual says whether there is such an input and how to set it up.
• Generator through a changeover switch or ATS feeding the backup circuit or the whole house.

What Ukraine's State Energy Supervision Inspectorate says:

• a generator may be connected to the house wiring only through a changeover switch or an automatic transfer switch (ATS) placed after the meter and the main breaker, so the generator cannot energise the public grid;
• do not plug into a socket a generator whose power far exceeds what the socket can carry — the inspectorate gives 10 A ≈ 2.2 kW or 15 A ≈ 3.5 kW for sockets;
• the generator stands outdoors, at least 6 m from windows, doors and garages, protected from rain; the connection should be made by a professional.

The Distribution System Code (clause 11.5.10) adds that the owner of a backup power source is responsible for its condition, and that damage from an unauthorised start of a backup source is paid for by its owner.

For comparison, using SolarPlan's assumptions: a 5.5 kW petrol generator at a light load burns about 0.8 litres an hour, so a 25-litre tank lasts about 31 hours — but every hour costs fuel and servicing. A battery is silent and needs no fuel, but holds a limited reserve. A five-year comparison is on the home backup power page.

What if you live in a flat?

A flat usually has no roof of its own, and generators are banned there (balconies included). That leaves three realistic options:

1. A portable power station (a battery with sockets). Nothing is installed: you charge it while the power is on and plug appliances straight in. In SolarPlan's model a 2 kWh station runs 0.4 kW for about 4 hours. Good for a router, lights, laptops and phones; for a fridge, check the station's peak power.
2. A battery with an inverter in the flat's panel. An electrician moves the essential sockets and lights to a backup circuit, and the inverter switches them to the battery automatically. It costs more, but there is no carrying appliances around or hunting for extension leads.
3. A shared system on the building's roof, through the owners' association (OSBB) — a separate project for the whole building.

If the power goes off on a rolling schedule (a few hours off, a few hours on), the battery must refill between outages. SolarPlan checks this in its apartment plan: choose your appliances and outage length on the plan page.

How can you finance a backup system?

Owners of private houses can use Ukraine's state energy loan: UAH 10,000 to 480,000, at 0% in the first year, 5% in the second and 7% in the third. Once the equipment is installed, the state repays 20–30% depending on the kit, with the largest share for solar plus a battery and a generator. We cover the kits and the EBRD-backed alternative in our article on the state energy loan for private houses and on the financing page. Terms change, so confirm them with the bank before you buy.

Choosing a setup for your outages

• Rare, short outages, the goal is lower bills: on-grid, with a battery later (check that the inverter supports it).
• Regular outages of up to 8–12 hours: hybrid with a 10–15 kWh battery and a backup circuit.
• Long winter outages: hybrid plus a generator through the inverter's input or an ATS.
• A flat: a portable power station or a battery with an inverter in the flat's panel.

Rather than guess, start a free plan: SolarPlan lays out panels on your roof in 2D and 3D, sizes a battery for your appliances and outage hours, shows the price and payback, and then lets you get offers from verified installers in one format. It costs you nothing. Technical rules change, so agree the final wiring with your installer and your local grid operator.