Photovoltaic dreaming, our fifth entry on solar power commercialization in our CleanTechnica miniseries celebrating the UN’s 2015 Year of Light, is based on physicist John Perlin’s writings in his book Let It Shine: The 6000-Year Story of Solar Energy. Perlin’s work is the only book that has thoroughly chronicled the development and application of solar throughout time, focusing on key themes, people, and events that have laid the foundation for an enduring Solar Age.
The previous episode featured the discovery of the photovoltaic effect by William Grylls Adams and Richard Day Evans.
Our fifth post concerns what happened after news of the photovoltaic effect had reached other scientists, inspiring Charles Fritts, an American inventor, who built the first solar panels in 1881. They produced a current, Fritts reported, “that is continuous, constant and of considerable force not only by exposure to sunlight but also to dim, diffused daylight.”
In the third post of our miniseries, we finished reporting on Willoughby Smith and his startling experiments proving the photosensitivity of selenium. The year: 1872. It was this discovery that stirred keen interest in two British scientists, William Grylls Adams and Richard Evans Day. (Other previous posts in this miniseries: Author John Perlin Celebrates the Coming Year of Light, Author John Perlin & the Solar Cell, The Pathway to Today’s Solar Revolution: Discovering the Photosensitivity of Selenium, and Photovoltaics Discovered in 1875: Interview with Author John Perlin.)
Here, Perlin elaborates on the sequence of events following news of the photovoltaic effect.
CleanTechnica: To protect his work, what patents or other business strategies did Fritts deploy?
Perlin: To insure scientific recognition of his panels, he sent a number of them to Werner von Siemens – the Edison of Europe – to test them at the Prussian Academy in Germany.
CleanTechnica: What was the reaction from Europe?
Perlin: Their performance so impressed Siemens that he judged the direct conversion of light into electricity to be “scientifically of the most far-reaching importance,” urging a “thorough investigation to determine upon what the electromotive light-action of selenium panels depend.”
CleanTechnica: But this was not to be, however, for the solar panel of Fritts. Correct?
Perlin: Sadly. Few heeded Siemens’ call for action. The public’s eye was focused on a different type of electrical generator — the first electric power plant, just built by Thomas Edison, and powered by coal. Who would take Fritts seriously when he boasted that his solar electric plates would soon compete with Edison’s?
Worse, the vast majority of scientists summarily dismissed the idea that light could by itself generate electricity without first being turned into heat that could power a turbine. Their obsession with heat as the only means of driving engines led them to this conclusion. The panels also appeared to generate power without fuel and without moving parts, making them even more suspect, easily rejecting them as perpetual motion machines.
Clean Technica: Most scientists seemed to believe solar heat was the only way to drive engines which might generate electricity. But not all. Correct?
Perlin: Several daring scientists disagreed. One of them, George Minchen, a professor of Applied Mathematics, charged that his colleagues’ disinterest and denigration of photovoltaics was based on “very limited experience” and “from a so far as we know perspective,” which, Minchin charged, “was nothing short of madness.”
Minchin came the closest of all nineteenth-century scientists to explain what happened when light strikes a solar cell. “Perhaps,” he wrote, it “simply acts as a transformer of the energy it receives from the sun, which its own materials, being the implements used in the process maybe wholly unmodified.” And only when science had the capability of quantifying “the intensities of light as regards each of its individual colors [that is the different wave lengths], Minchin argued, could science judge the potential of photovoltaics.
CleanTechnica: What was to become of Minchen?
Perlin: Minchin was heading on the right path but photovoltaics’ scientific vindication had to wait another twenty years for Einstein’s revolutionary breakthroughs regarding light and the energy of the sun, which will be discussed in the next two episodes of our miniseries.
CleanTechnica: I thought Becquerel discovered the photovoltaic effect.
Perlin: So does almost everyone else but this is not so. Becquerel discovered the photogalvanic, that is, the photochemical effect, as he had exposed to sunlight a device that had two electrodes on either side of an electrolyte. It was Adams and Day who discovered the photovoltaic effect in a solid-state material from which almost every installed PV module has evolved.
Next we visit Albert Einstein.