Temperature Coefficient and Performance in High Temperatures

Context: During operation, PV modules are inevitably influenced by temperature, and the cell structure directly determines performance under heat.

Technological differences: The temperature coefficient of PERC is typically around -0.34 %/°C, TOPCon at -0.32 %/°C, equivalent to a power loss of about 0.3 % per additional degree. IBC modules with back-contact reach about -0.29 %/°C, while HJT with heterojunction technology achieves even lower values around -0.243 %/°C.

Real impact: In Europe, summer air temperatures often rise to 28–32 °C, while the module surface can reach 60–65 °C under sunlight. Compared with STC (25 °C), an increase of 35–40 °C means:

• PERC modules lose approx. 11.9–13.6 % power;
• TOPCon approx. 11.2–12.8 %;
• IBC approx. 10.2–11.6 %;
• HJT only 8.5–9.7 %.

This difference adds up to several thousand kWh per year and directly affects long-term revenues.

Further comparison: At surface temperatures above 45 °C, losses are: PERC 15.3 %; TOPCon 14.4 %; IBC 13.1 %; HJT 10.9 %. This shows: Under extreme heat, HJT is clearly advantageous, IBC remains stable, and both ensure higher production continuity than PERC and TOPCon.

Investment relevance: Across Europe, on dark industrial rooftops or during summer electricity price peaks, a lower temperature coefficient significantly improves cash flow stability. In other words: the temperature coefficient is not a minor detail, but a decisive factor for real returns.

Applicability of Glass-Foil and Glass-Glass Modules

Context: The choice between glass-foil and glass-glass is not a simple matter of pros and cons but depends on cell technology and application scenario.

Market experience with glass-foil: PERC modules in glass-foil design were installed more than ten years ago and continue to operate stably in many places with 85–90 % of their initial output. For roofs with low load capacity or restricted installation conditions, glass-foil remains a valid option – lightweight, easy to install, and reliable when correctly certified.

Structural advantages of glass-glass: Double glass layers provide tighter encapsulation, higher resistance to moisture and heat, lower PID risk, and slower power degradation. The annual degradation factor is about 0.1–0.2 % lower than glass-foil, which means 3–5 % higher yield over 25–30 years. Thus, glass-glass is especially useful for industrial halls or agri-PV with long lifespans – despite higher weight and more difficult handling.

Why IBC glass-foil is “the optimal choice among glass-foil”:

Structural compatibility: IBC shifts anode and cathode to the back side, with fewer soldering points and lower failure risks. This makes the technology particularly suitable for glass-foil – reliable and lightweight.

Performance under heat: At approx. -0.29 %/°C, an IBC glass-foil module loses only 10.2–11.6 % at +35–40 °C. In comparison: PERC (-0.34 %/°C) loses 11.9–13.6 %, TOPCon (-0.32 %/°C) 11.2–12.8 %. IBC therefore ensures more stable summer yields.

Costs: Lower weight makes transport, installation, and permitting easier – ideal for old or weak roofs. This increases installation speed and reduces costs, often resulting in a more favorable ROI.

When to prefer glass-glass: In conditions with high humidity, salt or ammonia exposure, heavy snow load, or a 30-year operating horizon, glass-glass is the safer choice. HJT and TOPCon are mostly used in glass-glass configurations here.

Investment judgment: Glass-foil vs. glass-glass is a question of “technology × application”:
• Limited load capacity, tight conditions, hot summers, fast ROI → glass-foil, especially IBC glass-foil.
• Harsh environments, very long lifespans, degradation sensitivity → glass-glass.

Certifications and Warranties

Context: For rooftop and industrial projects, certifications and warranties form the basis for safety, environmental compliance, and long-term stability.

Sustainability and safety standards: Our modules comply with European RoHS directives, reduce the use of hazardous substances, and increase the environmental friendliness of photovoltaic systems.

International certifications: With tests such as TÜV and CE, our products are tested for humidity/temperature cycles, mechanical loads, and PID effects. These standards reflect material and process quality and guarantee reliability in the European market.

Long-term investment security: We offer a 25-year linear performance warranty as well as a product warranty. This supports investors with stable returns and minimized risks over the entire project lifespan.