Specific Yield

Quick Facts

Specific Yield Benchmarks (P50, Year 1)

Tracker vs. Fixed

Trackers raise specific yield by keeping modules closer to normal-incidence through the day, but the real-world gain depends heavily on how much backtracking the controller uses to avoid inter-row shading near sunrise and sunset — see our breakdown of the backtracking algorithm for solar trackers for how that trade-off is modeled.

Worked Example

100 MW plant in Bengaluru:

• Annual GHI: 1,920 kWh/m²/yr.
• POA irradiance after tilt (15°): 1,990 kWh/m²/yr.
• Performance ratio: 0.81.

Specific Yield = POA × PR
              = 1,990 × 0.81
              = 1,612 kWh/kWp/yr

Annual energy = 100,000 × 1,612 = 161 GWh/yr.

Year-by-Year Specific Yield (with degradation)

For a 0.5%/yr degradation rate:

• Year 1: 1,612 kWh/kWp.
• Year 5: 1,580.
• Year 10: 1,544.
• Year 25: 1,420.
• 25-year average: 1,510 kWh/kWp.

Common Mistakes

1. Comparing specific yield without normalizing to PR or POA.
2. Using year-1 number for 25-year revenue projections.
3. Confusing DC specific yield (rare) vs. AC specific yield (standard).
4. Ignoring availability/curtailment in real-world numbers.

Best Practices

• Report year-1, year-25, and 25-year average specific yield.
• Include statistical bands (P50, P90).
• Cite weather data source and EYA methodology.
• Compare to regional benchmarks for plausibility check.

Key Takeaways

• Specific yield = annual AC energy / DC nameplate, in kWh/kWp/year.
• Strong function of site irradiance, system efficiency (PR), and mounting (tracker vs. fixed).
• Benchmarks: 1,200–2,400 kWh/kWp globally; ~1,500–1,800 typical for utility-scale India and US sunbelt.
• Report year-1 and 25-year-average values for transparent investor communication.
• Specific yield × DC nameplate = annual revenue × tariff = headline project economics.

Related Reading

Specific yield only becomes a bankable number once it is backed by rigorous energy modeling. For how lenders and developers frame year-1 output against statistical bands, see P50, P90, and P99 in solar yield reports; the simulation tool used to generate that number matters too, which our comparison of PV yield simulation software and the step-by-step PVsyst tracker yield study methodology both cover in detail. Because trackers can lift specific yield by 15-25% over fixed tilt, engineers weighing that trade-off may also find our explainer on auto solar tracking systems useful. Once specific yield is modeled with confidence, the next step for most developers is translating it into project cash flows — a task covered by SurgePV’s solar generation financial modeling tool and QuickEstimate’s guide to solar financial modeling software.