The technology - polyZEBRA, German n-type back-contact cells
The planned Namibian plant is designed to manufacture polyZEBRA cells and modules, the n-type bifacial Interdigitated Back Contact (IBC) technology developed by ISC Konstanz in Germany. It is the newer generation of the ZEBRA platform, which has been in mass production under licence since 2020. The specifications below are the group’s module range, the same range across Insola projects.
Conversion efficiency above 25%
polyZEBRA is specified at a 25.5% cell design point. The preceding ZEBRA generation has been in commercial mass production since 2020, where average cell efficiency reached around 25% in 2024, with champion cells at 25.7%.
Bifacial gain
Every contact sits on the rear face, so there is no front-side shading and the rear face also generates. Under typical conditions the module yields 10% to 20% more than a monofacial one, and above 20% on high-albedo desert ground.
Temperature performance
The IBC architecture carries a temperature coefficient of about -0.29%/°C at cell level against roughly -0.37%/°C for standard PERC, so it holds power better in hot conditions. n-type silicon shows no detectable PID, LID or LeTID, and annual degradation runs at about 0.4%.
All-black module face
With no busbars on the front, the module has a uniform black front face. That suits facades and roofs where the panel is visible.
Technical overview
polyZEBRA cell architecture
An interdigitated back contact cell on mono-crystalline n-type silicon, specified at 25.5% cell efficiency on 182 mm wafers. The bifacial glass-glass laminate captures rear-side irradiance for additional yield. polyZEBRA combines mature process steps from TOPCon, ZEBRA and back-contact manufacturing, and runs on standard production equipment: tube diffusion furnaces and screen-printing metallisation.
- Cells processable on any wafer size from M6 to M12
- Sensor instrumentation and data analytics across the line
- Machine-learning quality control and predictive maintenance
Transferred into production twice
ISC Konstanz has transferred this technology into industrial production before: ZEBRA IBC to SPIC in China in 2020, the first mass production of IBC cells in the country, and to Valoe Cell in Lithuania in 2021. The 200 MW cell-and-module line at SPIC in Xining was ramped by a joint team of SPIC and ISC Konstanz process engineers and reached an average cell efficiency of around 24.2%.
Bifacial gain figures assume ground albedo above 25%, a module mounting height of 1.5 m, a ground cover ratio of no more than 40% and a mounting structure that leaves the module rear side clear. Specifications are indicative of the group range and subject to final product configuration.
Where the technology comes from - Origin and licence chain
ISC Konstanz developed the technology, EquuSol is the licensing party for the region, and a Namibian sub-licence would run from EquuSol with ISC Konstanz’s consent.
- ISC Konstanz. The International Solar Energy Research Center Konstanz, a German non-profit photovoltaics research institute founded in 2005 as a spin-off from the University of Konstanz, developed the ZEBRA and polyZEBRA back-contact cell technology and runs a formal technology-transfer programme alongside it.
- EquuSol Limited. EquuSol Limited, in Mauritius, is the group’s technology and intellectual property company and owns the Insola brand. The master licence for sub-Saharan Africa is in negotiation between ISC Konstanz and EquuSol.
- The Namibian sub-licence. The Namibian project company would hold a technology sub-licence from EquuSol. The grant of any such sub-licence remains subject to the prior written consent of ISC Konstanz and to separate sub-licence negotiations on terms acceptable to all parties.
- Technology transfer. The arrangement carries the process with it: training of engineers at ISC Konstanz, equipment specification and selection support, site acceptance testing, recipe implementation, commissioning and ramp-up to target performance.
Compliance & standards - Certification and testing
Modules are designed to meet the international photovoltaic standards for safety, performance and reliability. Modules built on this technology platform already hold IEC 61215, IEC 61730 and IEC 61701 certification in commercial production.
- Production standard. A 1 GW facility built around sensor instrumentation, data analytics and machine learning, for process optimisation, inline quality control and predictive maintenance.
- Degradation resistance. n-type silicon leaves the cells close to immune to light-induced and light-and-elevated-temperature-induced degradation, with no detectable evidence of PID, LID or LeTID. The warranted power schedule allows 1% in the first year and about 0.4% a year thereafter, ending at 87.4% in year 30.
- Design qualification. Module design qualification and safety testing to IEC 61215 and IEC 61730, with a static mechanical load rating of -2400 to +5400 Pa.
- Electrical safety. 1500 V DC maximum system voltage, a 30 A maximum series-fuse rating and IEC 61140 appliance class II.
A 1 GW plant for Namibia
See how the technology translates into a facility: scale, power, land and the engineering standard behind it.