25/02/2026
🔍 7 Major PVsyst Losses Every Solar Engineer Should Know ☀️⚡
When performing yield assessment in PVsyst, it’s not just about GHI, tilt, or module wattage.
Accuracy comes from how well you understand and model system losses.
Here are the 7 major PVsyst loss buckets that shape annual generation, PR, and bankability 👇
🔹 1️⃣ Thermal Loss
🔸 Module efficiency drops as cell temperature rises
🔸 Influenced by mounting structure, ventilation, wind speed, and ambient temperature
🔸 One of the largest losses in hot climates
🔹 2️⃣ Ohmic Loss (DC + AC)
🔸 DC cable losses due to conductor resistance
🔸 AC losses in cables, switchgear, and transformers
🔸 Transformer losses include iron (no-load) and copper (load) losses
🔸 Directly linked to cable sizing & layout design
🔹 3️⃣ Module Quality + LID + Mismatch
🔸 Manufacturing tolerance losses
🔸 Light Induced Degradation (LID)
🔸 Electrical mismatch between modules and strings
🔸 Strongly dependent on module selection & binning
🔹 4️⃣ Soiling Loss
🔸 Dust, pollution, bird droppings, and sand reduce irradiance
🔸 Highly site-specific and seasonal
🔸 Cleaning strategy has a direct PR impact
🔹 5️⃣ IAM Losses (Incidence Angle Modifier)
🔸 Reflection losses at low sun angles
🔸 Prominent during morning & evening hours
🔸 Influenced by glass type and anti-reflective coating
🔹 6️⃣ Auxiliaries Consumption
🔸 Energy consumed by SCADA systems
🔸 Inverter self-consumption
🔸 Trackers, cooling systems, control rooms, lighting
🔸 Often underestimated in early-stage simulations
🔹 7️⃣ Unavailability / Downtime
🔸 Grid outages
🔸 Inverter failures
🔸 Preventive & corrective maintenance shutdowns
🔸 Strongly tied to O&M strategy and grid reliability
🔧 Additional Important PVsyst Losses (Often Overlooked)
🔹 Near shading & far shading losses
🔹 Degradation losses over plant lifetime
🔹 Albedo uncertainty (especially for bifacial systems)
🔹 Grid curtailment & export limitation losses
📌Even 1–2% improvement across these losses can significantly enhance:
🔸 Annual Yield
🔸 Performance Ratio (PR)
🔸 Project feasibility & ROI
Currently exploring PVsyst in depth for yield assessment, feasibility studies, and performance optimization.
