Definition
Module efficiency is the ratio of electrical power output to incident solar power per unit area, measured at STC. Modern crystalline silicon modules: 20–24%. Determines kW per area for given site.
Module Efficiency by Technology (2024)
| Technology | Typical Efficiency | Premium |
|---|---|---|
| PERC | 20–21% | 21.5% |
| TOPCon | 22–22.5% | 23% |
| HJT | 22.5–23.5% | 24% |
| IBC | 22–23% | 24% (Maxeon) |
| CdTe (First Solar) | 18–19% | 19.5% |
| Tandem perovskite (lab) | 25%+ | n/a yet |
Efficiency vs. Area
A 22% efficient module of 2.1 m² delivers 462 W. A 19% efficient module of same size delivers 399 W — 14% less power per square meter.
Key Takeaways
- Module efficiency = electrical output / incident solar input.
- Modern c-Si: 20–24%; TOPCon and HJT dominate premium tier.
- Higher efficiency reduces land per MW but raises cost per Wp.
- LCOE optimum balances efficiency vs. cost; mid-tier often wins.
- Compare efficiency at STC; field efficiency is 75–85% of STC.
Frequently Asked Questions
4 commonly searched questions about Module Efficiency.
What is module efficiency?
Electrical power output / incident solar power. At STC: Pmax / (1000 W/m² × module area). A 450 W module of 2 m² = 22.5% efficiency.
Typical efficiencies (2024)?
PERC: 20–21%. TOPCon: 22–23%. HJT: 22–24%. CdTe (First Solar): 18–19%. IBC (SunPower Maxeon): 22%. Tandem perovskite (lab): 25%+.
Does higher efficiency mean less land?
Yes. Higher efficiency = more kW per m² = less land per MW. Useful for space-constrained sites like rooftops, carports.
Is the highest-efficiency module always best?
Not necessarily. Cost per Wp may be higher; the LCOE optimum often favors mid-efficiency premium modules over highest-efficiency boutique modules.
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