The maximum permitted capacity is linked to the contracted capacity of the electricity supply, expressed in kVA, rather than simply to the available installation area. Since installed PV capacity is expressed in kWp and supply capacity in kVA, the applicable conversion factor, based on the power factor (cosφ), generally results in a practical limit slightly below 100% of the nominal supply capacity. As a common safety guideline, the installed PV capacity should not exceed approximately 96% of the contracted supply capacity. The exact percentage may vary depending on the applicable scheme, such as net billing or zero feed-in, and should always be confirmed during the project assessment.
For installers: Check the contracted supply capacity, the applicable power factor (cosφ), and both the annual and 15-minute consumption profiles before sizing.
Yes. Under net billing, the value of the generated energy depends largely on how much is consumed at the time of generation, rather than solely on total annual production. Panel orientation should therefore be aligned with the facility’s consumption profile.
For installers: In commercial and industrial buildings, assess the distribution of generation throughout the day, not only the annual kWh/kWp yield.
Yes, self-consumption can be increased through battery storage, allowing surplus energy to be used later instead of being curtailed (zero-feed-in) or exported to the grid.
For installers: Battery selection should be based on the load profile, inverter capacity, and the intended energy-management strategy.
These three technologies differ primarily in efficiency, temperature coefficient, and cost. PERC is the most widely used and generally the most cost-effective option. TOPCon offers higher efficiency and improved performance at high temperatures, while HJT typically provides a lower temperature coefficient and longer service life, but at a higher cost.
For installers: On roofs with limited available space or high operating temperatures, TOPCon or HJT technology can often justify the additional cost through higher energy output per square metre.
Every solar panel has a power temperature coefficient, expressed as a percentage per degree Celsius. This is typically between approximately −0.3% and −0.4% per °C above the standard reference temperature of 25°C. In warm climates such as Greece, this may result in performance losses of approximately 10–15% during peak summer conditions.
For installers: Check the temperature coefficient in the product datasheet and ensure sufficient ventilation behind the panels, particularly in roof-integrated installations.
Bifacial panels generate electricity from both sides by capturing reflected solar radiation on the rear surface. They perform particularly well in ground-mounted installations with light-coloured or reflective surfaces, as well as on flat roofs, carports and tracking systems. On conventional pitched tiled roofs, the additional energy yield is generally very limited.
For installers: The additional cost of bifacial panels is mainly justified in ground-mounted systems with a mounting height above approximately one metre and a reflective ground surface.
This should generally be avoided. Panels with different power ratings, operating currents (Imp) or technologies can create mismatch losses when connected to the same string, as the string’s performance is limited by the lowest-performing panel. Even partial shading on a single panel can affect the output of the entire string.
For installers: When different panel models must be used because of availability, connect them to separate strings or MPPT inputs rather than combining them within the same string.