Fracsun alternative: sensorless soiling monitoring from inverter data
Fracsun’s station is the reference-cell benchmark for measured soiling. The alternative is not a different sensor, it is estimating soiling per inverter from data your plant already produces.
Fracsun (acquired by Nextpower in November 2025, station now sold as NX Clario) measures soiling precisely at one point per station, with hardware, water, and maintenance per unit. NuraVolt estimates soiling per inverter from production data with no hardware at all. Fleets choose software for spatial coverage and retrofit speed, stations for instrument-grade ground truth, and large plants increasingly combine both.
What Fracsun is, factually
Fracsun’s station compares two identical reference cells, one washed automatically each day and one left to soil, and reports the difference as measured soiling loss. It installs in under an hour, runs self-powered with cellular backhaul, and its published maintenance cadence includes annual water refills, a pump replacement around year five, and annual calibration. As of mid 2024 the network spanned 27 countries and over 12 GW of monitored capacity, and its CLEO model adds AI soiling simulation from weather and particulate data. In November 2025 Nextpower, the tracker manufacturer formerly known as Nextracker, acquired Fracsun outright, and the station is now marketed as NX Clario. Pricing is quote-only; no list price is public.
Where Fracsun wins
- Measured, not modeled: a washed-versus-soiled cell pair is physical ground truth, which independent engineers and lenders accept for bankability and resource assessment.
- Automated washing removes the manual-cleaning labor that made older soiling stations unpopular.
- Backing of the largest tracker OEM, with integration ambitions toward robotic cleaning.
- A published, credible maintenance and calibration regime rather than a black box.
Where the sensorless approach wins
| Dimension | Fracsun / NX Clario station | NuraVolt sensorless estimation |
|---|---|---|
| Coverage | One measured point per station | Every inverter in the fleet |
| Hardware | Station, mounting, comms, water per unit | None |
| Deployment | Procurement and installation per site | Days, from existing inverter or SCADA data |
| Maintenance | Water, pump, battery, annual calibration | None on site |
| Distributed C&I portfolios | Rarely economic per rooftop | Same pipeline as a single big plant |
| Bankability record | Established instrument standard | Emerging; calibrates against stations where present |
The structural argument comes from the industry’s own reference reports: IEA-PVPS documents that soiling is heterogeneous across a plant, that single-point measurements can misstate the real power impact, and that proper coverage needs a network of monitors whose cost is routinely underestimated. Per-inverter estimation is the only approach whose resolution matches that documented variability, and it reaches sites, like a 40-roof C&I portfolio, where nobody will ever install and water a station per roof.
The honest decision rule
If a lender or independent engineer requires an instrument record, or you are doing pre-construction resource assessment, buy the station; that is what it is for. If the job is operational, deciding which blocks or sites to clean this week and quantifying what soiling costs the portfolio, sensorless per-inverter estimation covers the whole fleet for less than the maintenance line of a station network. On large desert plants the strongest setup is both: NuraVolt calibrated against one or two stations, software providing the block-level ranking between station readings.
Frequently asked questions
See also
The full category comparison with IEA-PVPS evidence.
How soiling is detected from operational data.
Turning measurement into a cleaning decision.
Our published model accuracy on public data.
See this on your own plants
NuraVolt turns your SCADA and BMS data into early fault detection, degradation-aware BESS analytics, and audit-ready reporting. A fixed-scope audit shows you what we’d find on your portfolio.