How can an optimum energy output be achieved?
The optimum electricity production will be achieved if the PV-modules are directly aligned at a perfect angle to the sun to maximise annual energy generation. Shadowing should be avoided as far as possible since even small shadows can have a significantly negative effect. On modules with good rear ventilation the energy production will be better as extreme module temperatures result in a reduction of the efficiency of the cell. In BIPV-projects it is difficult to secure optimum conditions for electricity generation as the integration of PV will be a compromise between aesthetics, functionality and energy production. Therefore in most installations it is necessary to calculate the negative impact of reductions due to imperfect orientation, inclination or high cell temperatures. The performance of BIPV installation cannot be measured by its energy output alone. As a general rule it is considered that an acceptable level of reductions from the optimum output is no more than 50% in a BIPV
