Researchers from Spain found that semi-transparent PV systems are only commercially viable up to around 50% transparency, as higher transparency greatly reduces efficiency and increases system costs. Their analysis shows that declining power density, and not system balance or financing factors, are the main driver of higher LCOE, even in high-radiation areas.
A group of scientists from the University of Jaén in Spain have conducted technical and economic analyzes to assess the cost competitiveness of semi-transparent photovoltaic (STPV) technologies and found that commercial feasibility is possible if the transparency level does not exceed 50%.
“Unlike most previous studies, the analysis deliberately decouples the STPV economy from agricultural or construction income,” said the study’s lead author, Joao Gabriel Bessa. pv magazine. “This isolates the intrinsic cost performance of the PV system itself, making the results transferable between agricultural voltaic systems, BIPV and emerging hybrid applications.”
“The paper introduces a cost framework that explicitly links transparency to module costs, structural costs and system investments, using reference values from real utility-scale PV projects in Spain rather than idealized assumptions,” he continued. “The results explain why many STPV concepts look attractive on paper but struggle commercially, and where targeted policy instruments can realistically help without raising false expectations.”
In the study “Assessment of the cost competitiveness of semi-transparent photovoltaic systems”, published in Renewable energythe researchers explained that the cost of STPV modules is closely related to transparency levels, as power production per unit area decreases as transparency increases. This happens because the reduced cell surface area reduces energy generation without a corresponding reduction in non-cell material costs.
They also highlighted that Balance-of-System (BOS) costs in STPV systems increase as transparency increases, because the costs of mounting structures and DC cabling increase with the physical area of the PV generator. In contrast, the costs of inverters, AC cabling, transformers and other electrical components are largely independent of transparency levels.
The techno-economic analysis was based on a business case representing a 1 MW ground-mounted STPV system operating in Spain. To assess the influence of key financial and technical parameters on the system’s levelized cost of electricity (LCOE), the researchers conducted a sensitivity analysis.
Both assessments confirmed that system costs increase sharply as transparency increases. For example, an opaque system with 0% transparency would have an installation cost of €0.628 ($735)/W. However, with higher transparency levels, module efficiency starts to decrease and larger PV areas are required up to a capacity of 1 MW.
At a transparency of 50%, efficiency dropped to 10%, doubling the required surface area and increasing the total system costs to € 0.904/W. At 90% transparency, efficiency drops further to just 2%, necessitating a fivefold increase in surface area and increasing system costs to €3,110/W – almost five times higher than that of the opaque system.
“The research shows that semi-transparent PV systems only remain cost-competitive up to a moderate level of transparency. Above roughly 45-50% transparency, the LCOE increases sharply and exceeds typical electricity prices on the market, even in regions with high irradiation, such as southern Spain,” Bessa pointed out. “As transparency increases, power density falls faster than module costs because non-cell components such as glass, encapsulation, framing and logistics dominate the cost structure. This leads to a sharp increase in €/W module costs, even as less silicon is used.”
“Sensitivity analysis confirms that the annual specific output, expressed in kWh/kW, is the most influential parameter affecting the LCOE, outweighing capital expenditure and financing effects,” Bessa concludes. “In practical terms, optimizing layout, orientation and irradiation capture is more important than marginal cost reductions. High irradiation sites delay the point at which STPV becomes uncompetitive, but they do not eliminate it. Transparency remains the dominant driver in all scenarios. Policy can help, but it cannot override the underlying physics.”
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