Insight 05 · Energy plants
A solar plant judged against itself.
Solar went from a rooftop curiosity to a tenth of the world’s electricity in twenty years. The plants got bigger, the margins got thinner, and the question moved from “is it producing” to “is it producing what it should, and if not, which string”. This page is about how plant monitoring grew with the industry, what is moving now, the market in a few figures, how a modern plant is run, and what that returns.
Every stage asked the plant a sharper question.
First whether it produced. Then which string was weak. Then how it did against the sun it actually got, and now against what the grid will take. The question each time was the same: is it making what it should, and if not, where?
Small plants; the inverter’s own display; a monthly reading.
Production was known after the fact, for the plant as a whole.
Data loggers and web portals; string-level current measurement; a common Modbus register map for inverters (the SunSpec alliance, from 2009).
Equipment from different makers read the same way; a bad string could be found.
Utility-scale plants; SCADA; performance ratio against measured irradiance; weather stations on site.
The plant judged against the sun it actually got, not the sun on the datasheet.
Drones and thermal cameras; fault detection in the production data; batteries beside the plant.
Faults found from the air and from the curve; the plant stored as well as produced.
Three terawatts installed; curtailment and negative prices; export limits at the grid connection; batteries beside the plant as standard.
What the grid will take is now a constraint; a plant is run against its limit and its own history.
Curtailment is the new loss.
With solar at a tenth of world electricity, grids in several markets refuse output at midday; the energy a plant could have made is now a figure to track.
IEA PVPS · Snapshot of Global PV Markets · May 2026The export limit.
A fixed cap at the point of connection means the plant is managed against it, hour by hour, with batteries taking the surplus.
Expected from history.
A plant’s own curve for this hour and this irradiance is a yardstick the owner can check, once it has enough days.
Strings and inputs watched.
One input below its siblings on the same inverter is a fault long before the monthly figure shows it.
Read, never written.
Owners are asking for monitoring that reads the inverters’ standard registers and writes nothing, so the plant’s control stays with its own controllers.
of solar PV installed worldwide in 2025.
IEA PVPS · Snapshot of Global PV Markets · May 2026of solar PV installed worldwide in all.
IEA PVPS · same reportof 2025’s additions were utility-scale plants.
IEA PVPS · same reportof 2025’s additions were distributed PV.
IEA PVPS · same reportof renewable capacity expected worldwide 2025–2030.
pv magazine · IEA Renewables 2025 · 7 Oct 2025of it solar.
pv magazine · same reportThe underperforming string found.
Against its siblings, the same day, instead of in the quarterly report.
Expected that means something.
The plant’s own curve exposes soiling, degradation and shading as a drift from itself.
Curtailment counted.
What the grid refused is a number, so the case for a battery or a larger connection rests on it.
Fewer site visits.
The finding names the inverter and the input; the crew goes once, with the right part.
Control left where it belongs.
Monitoring that reads and never writes can’t trip a plant.
Portfolio in one view.
Every plant by its band — within, below, above, learning — worst first.
These are the mechanisms; the size of each depends on the plant and its connection. We don’t publish savings figures.
- 01
What the inverters publish
Power, energy, events and each input over Modbus, and the meter at the point of connection. Nothing written.
- 02
The weather station
Which makes performance ratio honest.
- 03
Findings and work orders
Each with the inverter, the input and the reading.
- 04
The battery
Its readings join the same path when the battery does.
Which radio and which device, for each step: the decision table →
Where we come in
Forty minutes, free, about your plants.
You leave with the five questions answered for one site and our view, in writing, on whether an assessment is worth doing. If you ask, you see the platform running; if you don’t, you won’t. Chirp Technologies advises plant owners and operators on this — which registers an inverter exposes, how to read a plant without touching its control, how to judge it against itself — and built HOLOIN, which runs on your own servers, for owners who want every plant’s production, health and findings in one place.