The Rise of High-Efficiency Modules is Reshaping Solar Economics

PERC technology defined India's first serious manufacturing phase. It was accessible, well-understood, and the manufacturing ecosystem around it was mature.

July 10, 2026. By News Bureau

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For the better part of a decade, the solar industry in India ran on one logic: make it cheaper. And by that measure, it worked extraordinarily well. Module prices fell 82 percent to 85 percent over fifteen years. Tariffs went from INR 17 per unit to under INR 2.7 in utility auctions. Solar became the cheapest source of new electricity generation in the country. That story is largely told.

But the industry is now at a point where driving module prices down further does not, by itself, make a project better. What makes a project better is how much energy it delivers over 25 years, how much land it needs, and how it holds up under Indian summer temperatures. That calculation is changing.

The PERC Era is Closing

PERC technology defined India's first serious manufacturing phase. It was accessible, well-understood, and the manufacturing ecosystem around it was mature. As recently as 2021, PERC held over 87 percent of the global market share. By 2025, that position had been taken by TOPCon, which now commands 87.6 percent of global new capacity additions, while PERC has fallen to just 3 percent. That is not a gradual shift. That is a technology generation changing over.

The reason it happened so fast is not that PERC became bad. It is that the gap in real-world performance between PERC and N-type technologies like TOPCon and HJT became too large to ignore once projects started running long enough to show it. Commercial PERC modules degrade at around 0.45 to 0.5 percent per year. TOPCon degrades at 0.35 to 0.4 percent. HJT drops further still, to 0.25 to 0.3 percent. Run those numbers forward over 25 years, and the gap in total energy delivered from the same installed capacity becomes significant enough that any developer who has modelled it stops treating it as a rounding error.

Why India’s Climate Makes this More Important, Not Less

There is one dimension of this conversation that is specifically Indian. All solar panels lose output as they heat up. PERC loses about 0.35 percent of its rated output for every degree above 25 degrees Celsius. TOPCon cuts that to 0.28 percent. HJT to 0.25 percent. Those numbers look small. They are not, once you factor in where our solar actually sits.

In April 2026, India hit a peak demand record of 256 GW in the middle of an early, intense heatwave. Rajasthan, where much of our utility-scale solar is installed, regularly crosses 45 degrees ambient in summer. A panel sitting in that environment and generating is running at 60 to 70 degrees Celsius. At that operating temperature, the difference between PERC and TOPCon or HJT in output per hour is not marginal. It is the kind of number that shows up clearly when you pull the actual generation data from a plant that has been running through Indian summers for a few years. That is not a small rounding error in the energy yield model. It is a material difference in what the project actually delivers versus what was promised when the PPA was signed.

The Balance-of-System Argument Nobody Talks About Enough

The efficiency conversation usually stays at the module level. It should not. When a module produces more watts per square metre, you need fewer modules, fewer mounting structures, less land, fewer installation days and less maintenance. These costs do not show up in a module price comparison, but they absolutely show up in the project IRR.

High-efficiency modules command a price premium. TOPCon sits 5 to 15 percent above PERC. HJT carries a 25 to 40 percent premium. On a per-watt basis, you look at that and think it is expensive. On a per-project-lifetime-unit-of-energy basis, the calculation often reverses. The real question for a developer is not what the module costs on day one. It is what the levelised cost of energy looks like in year 10 and year 20. That is where efficiency, temperature performance, and degradation rate all feed into the answer.

What this Means for Indian Manufacturing

For Indian manufacturers, this technology shift is both an opportunity and a real challenge. Building PERC was something India had learned to do well. Building TOPCon at scale requires different process parameters, different equipment, and a manufacturing discipline that takes time to develop properly. HJT requires even more. The capital cost of setting up a TOPCon line is around 30 percent higher than PERC. HJT is higher still.

Manufacturers investing in this now, commissioning N-type lines and building the process knowledge to run them consistently, are building a capability that will define the next decade of Indian solar manufacturing. It is not enough to produce high-efficiency modules on paper. They have to hold their rating in the field, year after year, under Indian conditions.

India’s ALMM framework is gradually reflecting this. TOPCon listings are growing. The policy direction is clear: the domestic market is being shaped to reward manufacturers who build quality into the process, not just capacity into the facility.

India has 283 GW of non-fossil capacity today and a 500 GW target by 2030. The pressure to build fast and build cheaply is not going away, and it should not. But a project commissioned in 2026 is going to run in 2045. The module chosen in the tender process this year determines what that project actually produces in 2038 and 2045, not just at commissioning.

The industry’s first phase was about proving solar could compete on price. That proof has been delivered. The next phase is about proving it can deliver on performance, reliably, in a country with extreme climate conditions, at the scale the target demands. High-efficiency modules are not a premium option in that context. They are the practical choice.

- Mayank Garg, CEO, Aroma Solar