When selecting the solar system for application, there are notable differences in system performance depending on the equipment selection. Some of the key concerns are: Energy Production, Fire Safety, Impact of Shade and finally Cost.
Typical system designs:
OK—Silicon modules + microinverters
In recent year microinverters have become more common. This design uses regular silicon modules with microinverters placed underneath the modules, attached to the same rack. This solution produces more electrical power, but the reliability of the most common microinverter is still unproven(due to use of electrolytic capacitors). Fire safety is increased as microinverters shutdown when firefighters disable AC power to the building.
Better—Silicon modules + string inverter
This is the historically the most common system, reliability is the best, fire safety is lowest. Budget conscious buyers like the low purchase price. Electrical production is lower, and the impact of even slight shade can substantially lower electrical production.
Best—Thin Film modules + Power Optimizers
Availability of high performance Stion thin film modules and advanced power optimizer components now produce a markedly improved system design. Thin film modules have the highest fire resistance rating, while being far less impacted by shade. When combined with advanced power optimizers, the system production can be a much as 25% improved over silicon modules + string inverter systems. This is possible without the reliability concerns of unproven microinverters. Additionally, thin film modules do not suffer the same high temperature power loss as silicon modules. Fire fighter safety is increased in similar fashion to that of microinverters.