Solar Tech Showdown: TOPCon vs HJT 

With 2026 coming into play the Indian solar industry is picking up pace, and domestic production is expected to cross 100GW via the PLI scheme, and the world will approach 500GW per year. Adani Solar and Waaree Energies are two Indian giants spearheading this shift with some of the most modern forms of the N-type technology: TOPCon (Tunnel Oxide Passivated Contact) modules made by Adani and HJT (Heterojunction Technology) panels made by Waaree.

They both have 23%+ efficiencies and low degradation rates together with robust climatic performance across deserts of Rajasthan to Kerala monsoons. Nevertheless, since the efficiencies of production can be only differentiated by 0.5-1, the actual choice of 2026 is reduced to a matter of cost efficiency, durability, temperature behaviour, and long-term output.

Topcon: the Scalable Powerhouse of Adani

The growing plant, 4GW now, 10GW by 2026-27, of Adani Solar at Mundra makes TOPCon one of the most economical replacements of PERC. With a thin coating of tunnel oxide and doped polysilicon deposited on the rear of the cell, TOPCon can be used to substantially reduce electron recombination, without any disruptive manufacturing overhaul.

The Shine and Elan Shine TOPCon modules produced by Adani have bifacial 144-cell versions with 550-575Wp, 21.4-22.4% module efficiency, and 80-85% bifaciality. G12R 210x182mm models are rated to 610Wp and 23 per cent efficiency.

The most important electrical parameters are:

Voc: 50.2–51.2V
Isc: Up to 14.17A
Temperature coefficient: -0.30 or -0.34 to -0.40%/o C (45oC = 7 to 8 percent loss)

Adani modules are LID-free and have an initial degradation of less than 2% in the first year and 0.55% thereafter with a resulting output of approximately 84.8 at 25 years. On reflective grounds, bifacial gains are up to 30, and thus they are appealing to utility parks.

Price 28-33/Wp, i.e. a 100kW system will cost 28-33 lakh, with 12-year product and 30-year performance warranty.

The vertically integrated supply chain provides stability to Adani due to the estimated 20 percent price changes on the raw materials in 2026. Field experiments, including in the textile business of Surat indicate an increase of textile output of about 15 percent over PERC in the presence of a lot of dust.
Limitations:
A little more heat sensitive than HJT and slightly lower damp-heat resistance, but new encapsulants minimize the difference.

Interpretation HJT: Premium Efficiency Bet of Waaree

Waaree Energies has 15.1GW of annual capacity and it is the pioneer of HJT as the next-generation high-performance technology. HJT involves stacking crystalline wafers with ultra-thin amorphous silicon layers facing each other to enhance passivation and energy capture in general.

The Waaree Plexus HJT series, dual-glass, bifacial modules, has to offer:

• 700–730Wp
• Efficiency of 23.5% (with lab results of 30.55)
• Bifaciality 85±10% beyond normal TOPCon levels.

Generational improvement was seen with a steady increase in efficiency of earlier generations (685715Wp) providing results of about 22.9% efficiency.

Some of the benefits of performance are:

• Temperature coefficient: -.25 percent/o C (5-6 percent loss at 45 o C)
• Degradation: 1 percent in the first year, and then 0.3 percent in each subsequent year 90 percent output in the 25 th year.
• Low-light advantage: approximately 5% improvement in the dawn/dusk.
• PID resistance: Ideal in coastal and damp climate.
• Price: 30 35/Wp, a 10-20 per cent. higher than TOPCon, with 30-year strong warrantees.

HJT manufacturing continues to rely on expensive components, like silver paste and CAPEX is approximately 50 percent higher than TOPCon. However, the low temperatures used in the manufacture process of HJT have future scaling potential.

Experimental results indicate that it is well thermally stable. Case An illustration of a 500kW pharma plant in Hyderabad with 20 lakh units/year production with lesser temperature-related downtime.

Limitations: Increased cost of production, slower scaling, and the remaining silver dependency are reasons why prices are still high.

Efficiency Face-Off: Meaningful Output, Marginal Gaps

Paperatically, HJT panels are predominant with 23.530 percent efficiency, as compared to the 21.423 percent efficiency in Adani TOPCon. But with mass implementation this is reduced to about 0.5-1%.

Key differentiators:

• BOS Savings: HJT will require fewer panels (7-8 vs 9-10) to be used to build 5kW array, which will save HJT 10-15 on racking/inverter costs.
• Bifaciality: HJT -85 -92% is better than TOPCon -80-90% producing 20-30% additional on reflective surfaces.
• Low-Light: HJT will improve by approximately 5 percent with clouds/monsoons; TOPCon is best with sunshine.
• Heat Tolerance: HJT drops 2 percent lower than TOPCon at 40 o C and above.
• Annual Yield: HJT yields more energy 5-10 per cent each year in mixed Indian climates as tested independently.

Value Advantage: Topcon Economics

The competitive advantage of TOPCon is that it is cost-effective. TOPCon conversion of PERC lines costs 30-40M/GW compared to substantially larger CAPEX of HJT. This results in:

TOPCon price: ₹28–33/Wp
HJT price: ₹30–35/Wp

TOPCon 100kW plant is saving 2-5 lakh of 100kW HJT

OPEX also prefers TOPCon where the production procedure is less complicated with only about 30 percent less maintenance expenses.But, HJT has a shorter payback period of 5-7 years compared with the 6-8 year payback period of TOPCon, due to slower degradation and higher productivity.

LCOE comparison:

• HJT: ₹2.5–3/kWh (best in hot climates)
• TOPCon: 2.8-3.2/kWh (utility scale and large industrial facilities are best)

TOPCon is more cost-effective in the larger EPC project and bulk procurement.

Degradation and Longevity: HJT Leads the Way

The performance difference between the long-term is evident:

• HJT, inherently resistant to LID/LeTID, is particularly applicable when the UV exposure is high in India, which adds a 5-10 percent lifetime yield benefit.
• TOPCon is very PID resistant with as much as 1-2% less performance in damp-heat tests, with 1-2% of the load in extreme humidity compared to HJT.

Also, dual-glass HJT modules minimize microcracks, which improve the durability in the long term.

Real World Performance: What Field Data Tells Us

• Adani TOPCon: A 1MW plant in the textile industry in Surat recorded 15% greater power, compared to PERC, recorded 1.5 crore units/year, even in the face of excessive dust levels.
• Waaree HJT: A 500kW pharma plant in Hyderabad had registered 20 lakh units per year and the temperature stability was better and less downtime.
• Industry exhibitions: TOPCon is at 24.5% and HJT at 25%+ with HJT achieving higher performance at low-irradiance.

HJT is the best performer in the monsoon/cloudy months and TOPCon in dry and high-irradiance seasons.

Which Wins in 2026? It All Depends on Your Usage

Utility scale, cost sensitive industrial plant (1MW and above):

Choose Adani TOPCon

• 15% cheaper
• Highly scalable
• High returns and dependability.
• Ideal in projects where the CAPEX efficiency is what counts.
• On high-quality commercial and residential fittings (50 -500kW):

Choose Waaree HJT

• Better heat performance
• Lower degradation
• Increased annual and lifelong energy production.
• Good in humid or hot or dark areas.

Market Outlook 2026: Though HJT is gaining momentum, TOPCon is still estimated to own close to 60 percent market share worldwide with the adoption of HJT growing as silver alternatives become commercially available.

Adani TOPCon and Waaree HJT are both Tier-1, ALMM-compliant modules that have been designed for the harsh climate of India. The deciding factor for you would be the temperature at the location, the area of the land, the amount of money you have, and what you value most between a long-term return of investment or something else. In India’s 2026 solar boom, you cannot simply pick one option that fits all cases. Rather, the correct choice is that which suits your particular ​project.