RoMoT – Robust Module Technology for High Solar Irradiance

The desert climate of the MENA region (Middle East and North Africa) presents major challenges for photovoltaic systems. Global radiation is around 1.5–2.5 times higher there than in more temperate climate zones and modules are subject to heavy soiling from aerosols, sand and dust. In addition, substantial variations in temperature as well as wear and tear due to frequent cleaning reduce both the yields and service life of the modules.

The RoMoT project focuses on developing reliable and high-yield PV modules for the MENA region. The aim is to improve module service life under the extreme local conditions and minimize typical losses in yield, thereby reducing electricity generation costs and improving investment security for stakeholders such as the KfW development bank or the German Investment and Development Corporation.

Measuring climatic conditions and developing test sequences

Meteorological data derived from satellite data delivers information on the site-specific ambient conditions for the PV modules. This makes it possible to systematically record the material-specific operating parameters for the modules and create simulation models for temperature, UV exposure, soiling and corrosion based on load spectra.

As the project proceeds, it will draw on empirical values regarding aging mechanisms in order to develop and define test sequences for evaluating module reliability in the respective climate zones and revealing specific weak points. Models will then be used to simulate micro-climatic stresses (UV exposure, temperature, humidity, etc.).

Developing and testing the glass coating and backsheet

The first step involves developing a durable anti-reflective or combination anti-reflective/anti-soiling coating and producing glass samples. The optimized formulations will then be transferred to a semi-automatic coating machine for small-scale samples and horizontal coating. The samples will be studied to assess the effects of layer structure, function and stability. Once the formulations have been validated, they can be tested in a large-scale production plant under real production conditions during ongoing operations.

Since UV radiation is a particularly critical factor in this region, the initial focus is on achieving a UV-stable backsheet. Safety-related factors such as electrical isolation characteristics and thermal resistance as well as the adhesion of the backsheet to the polymer used for encapsulation will be investigated and assessed. Since abrasion caused by sand and dust is a major factor in this region, the project also seeks to develop film formulations that are particularly resistant to these elements. The film samples will then be produced in large-scale plants for subsequent tasks.

Characterizing the module materials and optimizing module design

Materials for encapsulation, backsheets and solar glass that can realistically be used in industrial-scale production will be characterized, before being installed in various combinations in mini-modules and subjected to specific reliability inspections. The design of the modules will then be refined based on simulations and demonstrations run on STC-optimized module setups using MENA-qualified materials. A CTM yield analysis will be developed and will support the generation of efficiency analysis models for simulating module performance under typical operating conditions in the MENA region. Yield-optimized module designs will be defined and three full-format modules will be produced.

Validating the modules in an industrial production environment and testing the modules outdoors

The manufacturing process for the new module designs and materials will be tested in an industrial production environment. Any necessary adjustments to the existing production line will be analyzed and implemented for the production of samples. The properties of the glass and backsheets will then be analyzed and the materials, modules and components tested for reliability. The project will conclude with the testing of individual specimens outdoors in an arid environment (the Negev Desert or Gran Canaria). The trial run of the optimized PV modules will be monitored and documented.