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HJT capex cost curve: silver-to-copper transition closes the gap

Heterojunction (HJT) cell line capex has dropped from $130 million per GW in 2022 to $95 million per GW in early 2026, narrowing the gap with TOPCon ($85 million per GW). Silver-to-copper paste transition and indium-free TCO are the primary cost drivers. The cost crossover with TOPCon could arrive by 2027.

By Priya Sharma··2 min read

In 50 words: Heterojunction (HJT) cell line capex has dropped from $130 million per GW in 2022 to $95 million per GW in early 2026, narrowing the gap with TOPCon ($85 million per GW). Silver-to-copper paste transition and indium-free TCO are the primary cost drivers. The cost crossover with TOPCon could arrive by 2027.

The trajectory

HJT cell line capex per GW capacity:

  • 2022: $130 million
  • 2023: $118 million
  • 2024: $108 million
  • 2025: $100 million
  • Q1 2026: $95 million

TOPCon for comparison: $85 million per GW (relatively flat for 18 months).

The HJT premium over TOPCon has compressed from $45 million to $10 million per GW in three years.

What's driven the compression

Three factors:

  1. Silver paste reduction. HJT historically used 70%+ more silver per cell than TOPCon. Silver-to-copper plating transition has dropped silver usage 40–60%. This is the biggest single contributor.

  2. Indium-free TCO. Heterojunction historically required indium-rich transparent conductive oxide layers (ITO). Indium-free zinc-oxide-based TCO alternatives have reached commercial deployment, removing the indium supply risk premium.

  3. Equipment scale economies. As HJT line count globally has grown from <20 lines in 2022 to 80+ lines in 2026, equipment suppliers have achieved volume manufacturing economies of scale.

What's still expensive

Components keeping HJT capex above TOPCon:

  • More vacuum processing equipment
  • TCO sputter coating equipment
  • More complex passivation chemistry
  • Higher cleanroom requirements

When will crossover happen?

Industry consensus projections:

  • 2026 end: $90M (HJT) vs $84M (TOPCon) — gap $6M
  • 2027 end: $85M (HJT) vs $83M (TOPCon) — gap $2M
  • 2028: cost crossover likely, HJT slightly cheaper

What it means

If HJT achieves cost parity with TOPCon while maintaining its 0.2–0.4 percentage point efficiency advantage, the technology mix could shift meaningfully toward HJT.

Conservative forecast for 2028 cell shipment share:

  • TOPCon: 55–60% (down from 78% in 2026)
  • HJT: 25–30% (up from 11%)
  • Back-contact: 10–15%
  • Other: <5%

What developers should think about

For modules being procured for 2027+ commissioning:

  • HJT supply availability will improve
  • HJT premium over TOPCon will narrow further
  • Module-level cost comparison should be the procurement criterion, not cell technology

What to watch next

The 2026 silver paste consumption announcements from Tier 1 HJT producers — and the indium-free TCO commercial scaling — will determine whether the crossover happens in 2027 or slips to 2028.

Researched and drafted with AI assistance; reviewed and edited by the named editor within 24 hours of draft.

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