Performance Losses

The performance losses of colored PV are mainly due to the lower amount of photons that are transmitted to the solar cells, which in turn leads to lower current and reduced power production. Power losses for colored PV products now available on the market range from approximately 10% to 40%. Losses also strongly depend on the specific color, because each color is characterized by a specific reflection spectrum, according to Valckenborg.

“Pigment-based colors always absorb part of the spectrum. In this respect, paintings which can be considered better than others are those characterized by low absorption,” he claimed.

TNO is also reviewing these colored thermal solar panels.

In terms of higher performance, interference coating is currently the best option. Filters can be made with completely non-absorptive materials, and their reflection peak can be tuned to be as narrow as possible.

"Drawbacks of this technology are more related to price and other aspects, such as the angular dependency of the color," Valckenborg explained." In general, a compromise must always be found between electrical performance, cost and aesthetic quality.”

Vertical PV

One reason colored modules are still significantly more expensive than conventional panels is because the building industry is actually quite conservative, and for good reason, according to Valckenborg. As a facade element, BIPV colored modules must comply with strict safety requirements and be strong enough to avoid failures of any kind. “Because if something fails then the costs of repair can be huge,” he explained.

Colored modules are considered ideal for facade applications." First, because facades are much more visible than roofs," Valckenborg said." Secondly, because the euro/m2 for a facade is already significantly higher than for a pitched roof. So the relative added cost of color is much lower for the facade application."

Valckenborg noted that BIPV panels on pitched roofs are still a niche market.

"In the Netherlands we start to see more infrastructure integrated PV (IIPV), which includes all applications into noise barriers, dikes, and roads. Because these applications are visible, they might become colored one day," he concluded.