Mankind has looked to the Sun since the beginning of time. We have many written records of the ancient history of using the sun and many otf our leading scientists and technologists continue to find new ways to use this incredible resource.
Since mankind first started using tools, we can be sure that the Sun has been one of the most important part of our lives. Realizing how vital light and heat were to the individual and to any groupings of individuals, it is no surprise how early folklore tried to understand and explain the gifts of the Sun. Even today, we turn to science to answer some of those questions of how important the Sun is. Science tells us of the incredible energy generated – the Earth is just a small point in the expanding sphere of power generated by the Sun and is still struck with 174 petawatts (add fifteen zeros) of radiated photon energy at any moment. The energy sent to us by the Sun in an hour is about the same energy that mankind uses from all sources in about a year. Thirty percent of the energy is reflected back into space, most of the rest is absorbed in land and water. About one thousandth of one percent of the energy is converted by photosynthesis into biomass leading to all life including the conversion to fossil fuels like oil, gas, and coal. It is no wonder that there is so much industry involved in making this incredible resource into an even more useful part of our lives.
In anthropology, we find that even the most primitive people found value in orienting their homes to capture and retain solar energy. Aboriginal and classical ancient structures and devices show how our ancestors used their level of technology to improve their lives. Buildings and the use of natural structures throughout the world, the use of colored pottery in Africa, Asia, Europe, Australia, and the Americas show common solutions used by civilizations. In the writings of Socrates, we see one of the first discussions of the Sun in construction technology. He advised that homeowners not only consider windbreaks to protect against the cooing affects of the north wind but also the use of southern windows for bringing heat into the home and eaves for cooling houses during the day. Archimedes famously defeated Roman invaders with an early mirror weapon that caused the wooden ships and their sails to burst into flames. This spectacle was famously re-enacted in the late twentieth century by the Greek navy. Pliny the Younger described the uses of mica windows and the contemporary use of passive solar heat in bath houses and other buildings in the Roman Empire.
In modern times, we can see the linkages from discovery and innovation to each step of the renewable energy industry. The classical writings inspired concepts by Leonardo da Vinci and others to create solar furnaces and engines. In 1767, the first solar collector was patented by Horace de Saussared in Switzerland. Photoelectric effects were first described by Edmond Becquerel in 1839 and were investigated by a stream of scientists connected to Albert Einstein’s Nobel Prize in 1921 and on to current research today. Along the way, William Grylls Adams described a photovoltaic effect in selenium during his experiments in 1876. Other scientists were intrigued by this curious effect – such as Werner Siemens. This led to use of the effect in sensing and measuring light. It was 1953 before silicon was shown to generate a measurable amount of electricity in the presence of sunlight by Bell Laboratories. Initially they achieved about a 4% efficiency in generating electricity and eventually were able to show about an 11% efficiency. This is consistent with the efficiency typical to today’s homemade solar panels (5-10% efficiency). Commercial systems typically use solar panels with a fifteen to twenty percent efficiency although demonstration projects have been created with more than forty percent efficiency.
Many believe this is one of the big solutions to some of mankind’s biggest problems. Time will tell, of course. These few notes provide a small number of the highlights of science and technology. History has been described as a light on the stern of the ship of life. It shows only some ripples of what has already happened. If alternate energy is to be one of the big solutions, there is much more to be done in hopes of moving toward our best days.
