The inverter is the heart of a solar plant. It converts the panels' direct current into the alternating current your home runs on. The type of inverter decides whether you have power when the grid goes down.
Grid-tied inverter
Works only together with the grid: the panels power the house and the surplus goes to the grid. It is the cheapest option with the fastest payback.
The catch: when the grid switches off, a grid-tied inverter switches off too. This is a safety requirement so the plant does not feed voltage into a line where electricians may be working. During a blackout such a plant will not help, even in bright sunshine.
Off-grid inverter
Works with batteries and no grid connection. It suits cottages, remote sites and places with no grid at all. For a city house it is usually not the most convenient choice.
Hybrid inverter
Combines both worlds. It works with the grid, the panels and a battery at the same time. When the grid is on, the plant saves you money. When the grid drops, the inverter switches to the battery and panels in a fraction of a second, and the house keeps running.
What we recommend in Ukraine
For most private homes and small businesses we recommend a hybrid system. It costs more than a grid-tied one but solves two problems at once: lower bills and protection from outages. You can add a battery later if you install a hybrid inverter from the start.