Is thin-film best for offshore PV?

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Scientists from Italy’s University of Naples Federico II and India’s M Kumarasamy College of Engineering have recommended thin-film solar module technology for offshore floating PV projects.

The researchers said lightweight thin-film panels are better suited to projects with complex logistical requirements than conventional crystalline silicon alternatives, which must be mounted on pontoons and require aluminum frames and structures to resist saltwater corrosion.

The fact thin-film modules would be in direct contact with water, rather than being pontoon-mounted, offers cooling and cleaning benefits, according to the researchers, who say the logistics advantages also make thin-film technology better suited to land-based projects in remote locations.

Polymer laminate

A thin-film floating PV system could feature a single scalable array of panels linked by connectors, either in series or parallel, based on project capacity. Floating thin-film panels are usually laminated with a highly transparent waterproof polymer. Air pockets and ducts are embedded in panels during the lamination process to reduce rigidity and increase buoyancy.

Such arrays could be ideal solutions for offshore projects, said the researchers, which can be subject to strong winds and high waves.

“Analyses based on … flexural rigidity [bend strength] have proved that … thin-film-technology-based FPV [floating PV] on offshore [projects] will tend to have low wave energy interaction,” stated the Indo-Italian group in the paper, Floating Photovoltaic Thin Film Technology—A Review, published in Intelligent Manufacturing and Energy Sustainability.

The researchers said the hydrodynamic properties of thin-film panels can reduce mechanical stress on mooring systems. That means less infrastructure so project logistics are simpler than for crystalline silicon panels.

The researchers reviewed thin-film technologies which could be adopted for floating PV, including amorphous silicon (a-Si); cadmium telluride (CdTe); copper, indium, gallium and selenium (CIGS); and gallium arsenide (GaAs) products.

This article was extensively revised on 27/02/20 in response to feedback from the pv magazine community, below.