Following testing by DNV at a rooftop project in the Italian city of Milan during January, it concluded that Trinasolar’s Vertex S+ 500W+ mono-facial modules can reduce balance of system (BOS) costs by up to 2.27%, levelized cost of energy (LCOE) by up to 4.24% and structural costs by up to 12.01% when compared with three reference modules based on n-type technology.