Why 2030 needs a scenario, not a forecast
A capital allocator planning a 2028 procurement contract, a 2030 site-design assumption, or a multi-year hedging position against module ASP does not need one confident number. They need to know the range the credible sources actually span, and why. Four organisations publish the roadmap data this model draws on, ITRPV (VDMA's International Technology Roadmap for Photovoltaics), CPIA (China's national industry association), Exawatt and NREL, and on the metrics that matter most for planning, they disagree by wide margins. On back-contact cell share by 2030 alone, published estimates range from 15% to 35%: more than double, from source to source, on the same calendar year.
That range is not noise to be averaged away. It reflects genuinely different read on the same transition: shipment-data trackers, capacity-announcement trackers and lab-record trackers are each watching a different leading indicator, and each is right about what it measures. This report keeps the disagreement explicit, as three named scenarios, and gives a planning read for each one rather than collapsing it into a single defensible-sounding midpoint.
The three-scenario framework for 2030
Seven metrics carry the planning weight. Each scenario endpoint below is sourced to a specific roadmap position, not derived by splitting a difference.
| Metric | 2025 | 2030 low | 2030 base | 2030 high |
|---|---|---|---|---|
| TOPCon shipment share | 65% | 50% | 60% | 70% |
| Back-contact (BC / XBC) shipment share | 7% | 15% | 23% | 35% |
| HJT / SHJ shipment share | 4.5% | 3% | 8% | 15% |
| Perovskite-silicon tandem shipment share | 0.3% | 0.5% | 2% | 5% |
| Commercial module efficiency, weighted average | 23.5% | 24.0% | 25.0% | 26.0% |
| Utility flagship module power | 770 Wp | 750 Wp | 800 Wp | 900 Wp |
| Global module ASP, ex-tariff | US$0.09/Wp | US$0.06/Wp | US$0.08/Wp | US$0.10/Wp |
Full eleven-metric table, including n-type wafer share and wafer-thickness endpoints, and the complete anchor-by-anchor sourcing: review.solar/roadmap.
Near-term procurement, 2026-2027
For contracts and specifications locking in within the next two years, TOPCon is the market consensus, not a forward-looking bet: it already holds roughly two-thirds of shipments and every scenario, including the low case, keeps it above 50% through the rest of the decade. Specifying TOPCon as the sourcing default carries the least supply and pricing risk of any architecture choice available today.
Back-contact is the architecture worth active qualification now rather than later. Committed and built back-contact capacity from LONGi and Aiko Solar alone already exceeds 100 GW, running ahead of the more conservative roadmap trajectories, which is why this model's base case (23%) sits at the upper end of what a cautious planner might have assumed even twelve months ago. A procurement team that waits for back-contact to become the obvious choice will be qualifying suppliers after the pricing advantage of early volume has already gone to competitors who moved first.
HJT is the architecture to plan against with the most caution, not because the technology is weak, but because its own roadmap has proven unstable: CPIA's China roadmap cut its 2030 HJT forecast from 20% to 7.5% within about a year, tracking real financial distress at Meyer Burger and a continued shift of investment toward back-contact and tandem at several major cell makers. A specification or supply agreement built on an assumption of rapid HJT scale-up should be revisited against the latest roadmap vintage before it is finalised, not the vintage that was current when planning began.
Mid-decade capacity and budget planning, 2028-2030
For site-design and land-yield assumptions running to 2030, the efficiency band (24.0-26.0% weighted average) and utility flagship power band (750-900 Wp) bracket the reasonable range for capacity-per-hectare modelling; using the high end of either band as a base-case planning assumption understates land or roof-area requirements if the base case, not the high case, is what actually ships. For budget and hedging models against module ASP, the US$0.06-0.10/Wp ex-tariff band should be read alongside, not instead of, the specific tariff regime a given jurisdiction applies: US landed prices in 2025-2026 ran materially above this global ex-tariff band because of AD/CVD duties, and any procurement model that ignores jurisdiction-specific trade policy will misprice the delivered cost regardless of which global scenario proves correct.
Tandem is the technology to track, not to plan around, for anything closing before 2028. Every scenario, including the high case, keeps commercial tandem share under 5% through 2030, even though lab efficiency records (above 34% by 2026) are running well ahead of most roadmaps' expectations for the early 2030s. A capital plan that assumes near-term tandem availability at scale is planning against the lab record, not the factory schedule; the two are running on genuinely different clocks in this specific technology.
The roadmap-volatility risk itself
The single most useful planning fact in this dataset is not any individual scenario endpoint. It is that the roadmaps themselves keep moving. N-type mono-Si wafer share was reported at 70% for 2024; by mid-2026, the newest industry roadmap put the 2025 figure at approximately 82%, a twelve-point jump inside twelve months, already ahead of most 2024-vintage roadmaps' full multi-year path to that level. CPIA revised its own HJT forecast down by more than half in about a year. ITRPV revised its own back-contact long-run share upward in its most recent edition. None of these are forecasting failures in the ordinary sense; they are evidence that an industry mid-transition moves faster than annual roadmap-publication cycles can fully capture.
The planning implication is structural, not a caveat to footnote. Any procurement contract, capital commitment or specification built on a single-point 2030 assumption should be revisited against the current roadmap vintage on at least an annual cycle, and the further out the commitment horizon, the wider the band that should inform contingency planning, not the narrower one. A base case is a planning anchor. It is not a number to build a fixed multi-year agreement around without a revisit clause.
What this model does not cover
Three scope limits matter for anyone applying these numbers directly. First, the ASP band is a global ex-tariff figure: it excludes region-specific trade-barrier premiums, which in 2025-2026 nearly tripled effective landed cost in some jurisdictions relative to the ex-China baseline. Second, the tandem scenario band is a bound on commercial shipment share, not a technology forecast: it says nothing about when, or whether, a specific supplier's tandem product will be bankable at the volume a given project needs. Third, this model tracks published third-party roadmaps (ITRPV, CPIA, Exawatt, NREL) rather than generating an independent proprietary forecast: every number here traces to a named source, and where sources disagree, that disagreement is preserved as the scenario spread rather than resolved by assumption.