Thin Film Solar Cell vs Crystalline Silicon Wafers
A thin film solar cell is made by depositing one or more layers of photovoltaic material on a ceramic substrate. There are a handful of different photovoltaic materials used to create these types of cells. These materials are amorphous silicon (a-Si), cadium telluride (CdTe) and copper indium gallium selenide (CIS or CIGS). Thin film cells are laminated to produce a weather-resistant and environmentally-robust module.
The technique for making single crystalline silicon involves lowering a seed of silicon crystalline into a vat of molten silicon. As the seed gets lifted out, atoms of the molten silicon solidify around the seed, thus creating a long cylindrical silicon ingot. The ingot can be sliced into wafers. These wafers are fused together and sandwiched between two thick sheets of glass.
The voltage rate for modules that use crystalline silicon are 80-85% vs thin film, which is 72-78%. The module efficiency is 13-19% for modules made with crystalline silicon. The module efficiency for modules constructed with thin film technology are 4-12%. The installation of thin film pv modules can be considerably less than modules produced with crystalline silicon, because these require mounting systems for roof based or ground based systems. Thin film modules will require more circuit combiners and fuses and it requires more space to produce the same 1000 kiloWatts of power. Crystalline silicon will likely win in area-constrained applications in which power density is critical, and thin film will likely lead a competitive run-off in a non-area constrained, lower-sunlight application. Stephen O’Rourke, the Managing Director of Deutsch Bank Securities believes that they is no clear winner, yet. “Based upon real data, and reasonable assumptions for technologies soon to enter production, cost/kWh for several solar PV technologies are clustered within 10% of each other. Despite claims of clear-cut winners, the economics of solar PV-generated electricity points toward more than one technology solution.”
With GE’s new commitment to build a $600 million solar plant dedicated to thin film technology, the battle lines between thin film and crystalline silicon will be further entrenched. This certainly isn’t bad for our renewable and sustainability efforts.