Three cell technologies dominate every module quote in 2026: PERC, the outgoing P-type workhorse; TOPCon, the new N-type mainstream; and HJT, the premium performer. The right choice depends on your climate, your mounting configuration and your electricity price — not on which datasheet has the biggest headline number. Here is the complete comparison, ending with a recommendation by project type.
The three technologies in brief
- PERC (Passivated Emitter and Rear Cell) — P-type silicon with a rear passivation layer. The dominant technology of 2017–2023, now being phased out of tier-1 production lines.
- TOPCon (Tunnel Oxide Passivated Contact) — N-type silicon with an ultra-thin oxide layer that dramatically reduces recombination losses. The 2026 volume mainstream.
- HJT (Heterojunction) — N-type crystalline wafer sandwiched between amorphous silicon layers. Highest efficiency and best temperature behaviour, produced in smaller volumes.
Head-to-head specification table
| Parameter | PERC | TOPCon | HJT |
|---|---|---|---|
| Module efficiency (2026 mainstream) | 20.5–21.5% | 22.0–23.0% | 22.5–23.5% |
| Temperature coefficient (Pmax) | −0.34%/°C | −0.29%/°C | −0.24%/°C |
| Bifaciality factor | ~70% | 80–85% | 90%+ |
| First-year degradation | ~2.0% | ~1.0% | ~1.0% |
| Linear annual degradation | ~0.45% | ~0.40% | ~0.25–0.30% |
| Performance warranty | 25 yr / 84.8% | 30 yr / 87.4% | 30 yr / 88%+ |
| Price position (2026) | Baseline | +$0.005–0.01/W | +$0.015–0.03/W |
Energy yield: where the differences bite
Efficiency headlines decide nothing on their own — what matters is delivered kWh per kWp installed. Three effects separate the technologies in the field:
- Heat. At 65°C cell temperature, PERC gives up ~13.6% of rated power, TOPCon ~11.6%, HJT ~9.6%. In hot climates this alone is worth 2–3% annual yield. See our temperature coefficient guide.
- Rear-side gain. On ground mounts over grass (albedo ~0.2), bifacial TOPCon adds roughly 7–9% rear-side energy versus ~6% for bifacial PERC; HJT adds slightly more again. Over sand or white membrane the gap widens.
- Degradation. After 25 years, the compounding difference between 0.45%/yr and 0.30%/yr is roughly 4% of plant output — pure revenue in the tail years of a PPA.
Recommendation by project type
| Project profile | Buy | Why |
|---|---|---|
| Utility ground-mount, moderate climate | TOPCon bifacial | Best $/kWh — near-PERC pricing, N-type yield |
| C&I rooftop, hot climate (MENA, SEA) | TOPCon or HJT | Temperature coefficient dominates; HJT if the roof is space-constrained |
| Space-constrained roof, high tariff | HJT | Highest kWh per m² justifies the premium |
| Cost-driven project, mild climate | TOPCon | PERC's discount no longer covers its yield gap |
| Tracker + high-albedo site | TOPCon/HJT bifacial | Bifaciality factor converts albedo into revenue |
Supply reality check
Tier-1 manufacturers — LONGi, Jinko, Trina, JA Solar — have shifted the bulk of capacity to TOPCon, and premium PERC production is winding down. If your pipeline still specifies PERC, expect narrowing availability and shrinking choice of wattage bins rather than deeper discounts. HJT supply is concentrated in fewer factories; secure allocation early for large orders.
Econo Solar stocks TOPCon and HJT modules from all four brands with FOB Shanghai pricing returned within 24 hours. Send your project spec for current bin pricing.