Inverters, grid connection and plug-in solar
How Do Microinverters and String Inverters Differ, and Why Did Microinverters Lose Ground on Homes in 2025?
Summary
A string inverter converts the output of a whole row of panels in one box; microinverters sit on each panel and convert its output there. The string setup is cost-effective, but shade on one panel drags down the string, while a microinverter keeps one shaded or damaged panel from affecting the rest and can cost more. Berkeley Lab's 2026 data update found that the residential share of module-level power electronics fell sharply in 2025, tied to more homes adding batteries.
Side by side, in DOE's terms
| Item | String inverter | Microinverter |
|---|---|---|
| What it converts | A set of panels wired as one string | One panel |
| Shade or damage | A problem on one panel reduces production on the string | Shade or damage on one panel does not affect the power drawn from the others |
| Cost and service | Cost-effective; one unit is easier to cool and service | Can be more expensive |
Picture a 12-panel roof where three panels fall under a neighbor's tree every afternoon. On a single 12-panel string, those three pull down the whole string's output. With microinverters, the nine in the sun keep producing as usual.
What changed in 2025
Lawrence Berkeley National Laboratory's U.S. Distributed Solar and Storage 2026 Data Update (August 2026) groups microinverters and DC optimizers as module-level power electronics, or MLPE. Their share of the residential sample grew steadily until 2019 or 2020, when the market became saturated, and then dropped substantially in 2025.
The lab gives two reasons. Storage attachment on residential installs rose from 25% in 2024 to 37% in 2025, and more of those systems used the Tesla Powerwall 3, which has an integrated inverter and, in its typical DC-coupled setup, does not readily allow MLPE. DOE notes that solar can charge a battery directly over DC or after conversion to AC, and 2025 was the year the DC route spread.
Sources
- U.S. Department of Energy — Solar Integration: Inverters and Grid Services Basics
- U.S. Department of Energy — Solar Photovoltaic System Design Basics
- Lawrence Berkeley National Laboratory — U.S. Distributed Solar and Storage 2026 Data Update (August 2026)
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