BlackMagic is a simple, smart technology enabling solar inverters to harvest the energy that would normally be dispersed due to panel mismatch. All PV plants feature a degree of panels mismatch and it tends to increase over time. BM optimisers are simple an efficient, deliverying tangible energy gains even at the mildest levels of mismatch.
Conventional solar photovoltaic (PV) plants are made of strings of panels producing direct current (DC) and connected in series. Each string is then usually connected in parallel with other strings and eventually wired to an inverter, which in turn produces the alternate current (AC) and acts as the main interface with the grid.
The output generated by each string of panels is limited by the current of the lowest performing panel in that string. The energy that the best performing panels are not able to channel through the string is lost in the form of heat. The performance of each panel can vary considerably and is normally referred to as “panel mismatch” by those operating within the PV industry.
Panel mismatch occurs in all solar plants to various degrees, and is normally accounted for in overall performance and financial projections. The amount of energy lost due to panel mismatch is, however, considerable and can be conservatively estimated to account for at least 6% on ideally orientated commercial PV plants. Moreover, the energy that is normally lost due to panel mismatch is considered to be a limiting factor with regards to the identification of sites for new solar PV plants, as locations that offer a complex installation surface or that are affected by partial shading are usually discarded as unsuitable.
The causes of panel mismatch include, but are not limited to:
• Panel power tolerance (from factory): 3-5%
• Panel degradation: typically 0.2-2% p.a., average 0.8% p.a.
• Cell microcracks developed during the panel transport and installation, attributed to affect on average 6% of “delivered” panels based on recent studies
• Soiling and dust, affecting every panel to a varying degree. Typically, panel mismatch due to soiling is estimated to affect string performance by at least 1% (PVSyst estimate)
• System design: shading, tilt and orientation differences, particularly relevant to ground-mounted systems and plants installed on complex roof surfaces
BlackMagic power optimisers are simple, reliable electronic devices that harvest the maximum power from each panel in a string and can be used with virtually any panel and inverter on the market.
BlackMagic is the only optimiser on the market to offer the possibility to implement “selective optimisation”. PV installers and asset managers may choose to optimise just specific sections of a plant where mismatch is high, preferably optimising all strings connected to a specific inverter MPPT.
This way, optimisation can be targeted to the areas which can bring the highest benefits. Moreover, optimisation can be tested on a small section of a plant, and then extended to the rest of the system at a later date.