A solar cell has to absorb light to work.<\/p>\n
Anything that absorbs visible light is, by definition, not see through.<\/p>\n
That looks like a closed argument, and it is only closed if you assume sunlight is what the eye sees<\/strong>.<\/p>\n It is not. The visible band is a slice in the middle of a much wider spectrum.<\/p>\n Above and below it sit two large blocks of energy nobody has ever looked at.<\/p>\n So what if a window took only those<\/strong>?<\/p>\n Ultraviolet sits at the short end and near infrared at the long end, and between them they carry something close to half the energy arriving at the ground.<\/p>\n An organic semiconductor can be tuned. Change the molecule and you change which wavelengths it absorbs, which is not something silicon offers.<\/p>\n Tune it to take ultraviolet and near infrared and pass everything between, and the layer becomes invisible while working<\/strong>.<\/p>\n The cost of that is fixed and unavoidable.<\/p>\n You have given away the richest part of the spectrum before the cell has done anything, so the ceiling on efficiency is low by construction rather than by poor engineering.<\/p>\n There is a second product though, and it may matter more.<\/p>\n Blocking near infrared is exactly what an expensive solar control coating does, so the same layer cuts cooling load<\/strong> whether the wiring works or not.<\/p>\n The installation sits on the company’s own building in Santa Barbara.<\/p>\n Six insulating glass units went in, each measuring 40 by 60 inches<\/strong>, adding to about 100 square feet of facade in total.<\/p>\n That is one bay of a small commercial building, not a tower.<\/p>\n The coated lite is laminated and paired with a conventional low emissivity inboard lite and spacers supplied by an architectural glass fabricator.<\/p>\n A curtain wall contractor designed, supplied and installed the framing.<\/p>\n None of that is experimental hardware. The point of the exercise is that the unit is an ordinary window<\/strong> that a glazier can handle, ship and set with the tools already in the truck.<\/p>\n The company produced what it called the world’s largest fully transparent organic photovoltaic window in February of 2025, at that 40 by 60 inch size.<\/p>\n The facade followed in July of the same year and was described as the first commercial building integrated organic photovoltaic facade anywhere.<\/p>\n Its estimate is that a facade like this can offset roughly 20 to 25 percent<\/strong> of the energy a typical commercial property uses.<\/p>\n The chief executive’s statement was about the coating quality, the installation and the power generation already being seen from the first facade.<\/p>\n Efficiency for a fully transparent organic cell sits in the low single digits, well under a rooftop silicon panel.<\/p>\n That comparison is the wrong one<\/strong>, because nobody was going to put a silicon panel on a window.<\/p>\n The building belongs to the company, the estimate comes from the company, and no independently verified annual yield from this facade has been published.<\/p>\n The 20 to 25 percent figure is a modelled offset for a generic commercial property, not a reading taken off these six units.<\/p>\n Six windows is also not a facade<\/strong> in the engineering sense. It is a mock up at full scale, which is genuinely useful and is not the same as a building.<\/p>\n A tower puts thousands of units on four elevations with different orientations, different shading and different temperatures, and the yield curve for a north face is a different animal from a west one.<\/p>\n The question that decides everything for glazing is durability<\/strong>, because sealed insulating units carry warranties measured in decades and organic semiconductors are the part of this field with the shortest record under sustained ultraviolet.<\/p>\n Published efficiency records for transparent cells, unlike the certified numbers behind tandem modules<\/a> and record cells<\/a>, are thin on the ground.<\/p>\n The competitor is not a solar panel. It is plain high performance glass.<\/p>\n A good low emissivity coated unit already blocks most of the near infrared, already cuts the cooling bill and already costs a known amount per square foot.<\/p>\n So the commercial question is narrow: what does the electricity add, against the extra cost per square foot of the coated unit and the wiring, the inverters and the penetrations through the curtain wall that a plain window does not need?<\/p>\n That number will decide this, and it is not public.<\/p>\n What the installation does prove is that the units survive fabrication, shipping and setting, which is the step that has stopped most previous attempts, as trade coverage<\/a> of the install reported.<\/p>\n Getting solar windows<\/strong> through a glass factory is the hard part, as the announcement<\/a> makes clear.<\/p>\n Making them worth buying<\/strong> is the next one.<\/p>\n","protected":false},"excerpt":{"rendered":" A solar cell has to absorb light to work. Anything that absorbs visible light is, by definition, not see through. That looks like a closed argument, and it is only closed if you assume sunlight is what the eye sees. It is not. The visible band is a slice in the middle of a much wider … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":2199,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-2183","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-solar-power"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts\/2183","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/comments?post=2183"}],"version-history":[{"count":4,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts\/2183\/revisions"}],"predecessor-version":[{"id":2243,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts\/2183\/revisions\/2243"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/media\/2199"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/media?parent=2183"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/categories?post=2183"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/tags?post=2183"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Harvesting the two halves of the spectrum you cannot see<\/h2>\n
Six units and a hundred square feet<\/h2>\n
What has actually been announced<\/h2>\n
What has not been measured<\/h2>\n
The product it actually has to beat<\/h2>\n