What Drives the Cost of On-Site EL Inspection? A Breakdown of the Four Main Cost Components

ⓘ This article is currently published in Chinese. An English version is being prepared — read the Chinese original.

When a PV plant owner asks what an EL inspection campaign will cost, a single quoted number rarely helps — because the real cost is spread across four very different components: equipment access (owning, renting, or outsourcing), labor and field hours, generation loss from downtime, and image review plus reporting. This article breaks down each component, explains which variables move it up or down — night versus daytime operation, handheld versus drone-mounted imaging, whether the inspection can share an existing maintenance outage — and shows how the same campaign can differ severalfold in total cost depending on how these choices are combined. It also lists situations where spending on EL inspection is not justified at all, and closes with a practical FAQ on budgeting, cost sharing between owner and EPC, and how sampling ratios change the math.