Two or three years after the oil shock in 1974, a small group of Swiss scientists of various backgrounds and institutions (I was with Laboratories RCA in Zürich, a subsidiary of RCA corporation in the US) gathered privately in order to discuss the question of how to scope with the energy problem, in particular also whether solar photovoltaics in Switzerland would be a route to go. However, first a-Si cells, patented in 1977, had efficiencies in the range of less than 1%, obviously too small to contribute in a sensible way to the supply of electrical power. This would be certainly true for countries, where solar inputs are in the range of 1200 kWh/year, like in Switzerland, or less. The fabrication of the first crystalline Si cells and research goes back to the years between 1950 and 1960 induced by the emerging satellite technology. Best small-sized laboratory cells reached in the 1960s efficiencies of about 11%, which could be improved to about 17% in the 1970s. However, cells could be only produced at high cost. Cost was not a real problem for satellites, but it would be crucial for terrestrial large area solar photovoltaics. So some of us, including me, had doubts whether cell technology could be improved and cost reduced to a degree that it might substantially contribute to electrical energy supply. During these years I had many discussions with A. Rose, at that time one of the world’s leading scientist in photovoltaics and photoconductivity. He was convinced that human ingenuity would overcome these problems and that the abundant radiation of the sun to the earth could be tapped efficiently and at reasonable cost. Would this become reality?