In today’s age of global warming and the gradual depletion of our precious natural resources, solar energy can be considered as a boon to our threatened society. Therefore it is important to know what solar technology is, along with its history of inception. Such knowledge is not only beneficial for the sustainability of our future but will also help us to make maximum utilization.
Contrary to what people may think, solar energy is actually an age old technology. Its first known use can be traced back to 7th century B.C. The earliest solar power came in the form of glass pieces used to converge sun’s rays for fire. Although the initial use of solar power was mostly in the form of venerating the sun as a god who sustained life, the ancient Greeks and Romans saw the greater potential of the sun. They built their cities and houses in a solar reflexive manner and used glass to trap sunlight for warmth and energy.
First Solar Collector
In the year 1767 a Swiss environmentalist Horace-Benedict de Saussure tried to ascertain the usefulness of sunlight and the heat generated by it by inventing what is now known as a solar collector. He tried to capture the heat by making an insulated pine-wood box covered with three glass layers. Two smaller boxes were placed inside with black inner coating. When the sun’s rays infiltrated the glass cover, the blackened insides absorbed them thereby converting them into heat. While clear glass permits sunlight to enter and leave it, it stops heat from doing the same. Once this happens the heat is trapped in the box raising its temperature to almost 2300 F or 1100 C. This Hot Box was a rudimentary form of the first solar oven which Sir John Herschel used to cook food during his South African expedition in the 1830s.
Identifying the first photovoltaic effect in 1839 was a major breakthrough in the development of solar energy. Edmond Becquerel, a French scientist found out that electricity can be significantly augmented by putting two electrodes in an electrolyte and subjecting it to sunlight.
Photoconductivity of Selenium
Willoughby Smith in 1873 discovered photoconductivity of a chemical non-metal called selenium. Further in 1876 he found out that selenium emits solar energy. Although efforts were made in creating solar cells with selenium they were unsuccessful. However it established the very important fact that light could be converted into electricity by solid minus heat or any moving parts.
Solar Water Heater
During the 19th century there was the absence of any simple way of heating water. Chopped wood, coal or gas produced from it was used for heating purposes. This method, apart from being cumbersome, was quite hazardous too. In order to avoid such difficulties, a rather hassle-free and economical way of heating water was invented in 1891 by Heinrich Hertz. A black painted metal water tank was placed under the sun thereby enabling it to absorb as much heat as possible. However, this came with one major shortcoming. The water would take ages to get heated up and would rapidly cool down once the sun began to set.
In order to overcome this problem Clarence Kemp of Baltimore, USA, combined the metal tanks with the theory of the solar collector or the hot box. In doing so, not only was the heat trapped but also preserved for a much longer time. He named his invention the Climax.
William J. Bailey further modernized the Climax in 1909 with his copper collector. He divided the solar water heater into two parts:
1) A heating component exposed to the sun and
2) A copper insulated storage piece that was placed in the houses so families had access to heated water both day and night and as well as early next morning.
The first heating component was made up of pipes connected to a metal sheet painted black and put in a covered glass box. Since the water that required heating now passed through narrow pipes instead of being stored in a large tank, the quantity of water exposed to the sun at a single time was decreased, thus allowing the water to heat up quicker. Bailey named his device as Day and Night.
After Albert Einstein published his paper on the photoelectric effect in 1905, Robert Millikan in 1916 finally proved this effect. Here electrons are released from solid, liquid or gaseous matter as an effect of their assimilation of energy from electromagnetic radiation that has very short wavelength and high frequency. The photoelectric effect provided a thrust to the newly developing theory which proposed that light has a twofold characteristic – it concurrently retains the qualities of both waves and particles, each demonstrated as per the circumstances.
Post World War II solar power witnessed a gradual boost in its popularity particularly in the USA. In 1958 solar power was used to operate space exploration paraphernalia like satellites and space stations, thus debuting as a commercial use.
In 1958 the Vanguard I space satellite used about one watt of photovoltaic cells to fuel its radios. Vanguard II, Explorer III and Sputnik 3 were also dispatched with photovoltaic driven systems. Regardless of wavering efforts to commercialize the solar cell during the 1950s and 60s, it met with success as far as operating satellites were concerned.
Through the 1960s to the 1980s, specialists considered powering under-developed parts of the world (which house the majority of the world’s population) with an integrated system of electricity. However this proved to be a rather ambitious project, particularly in terms of economy. This led the World Electrical Council (WEC) to put greater emphasis on the need to popularize the use of solar energy. This initiative met with considerable success in parts of Central America, West Indies and Mexico.
Between the years 1959 and 1970 there were many crucial debates about the effectiveness of solar cells and about the cut back in its costs. The productivity of the solar cells then was only 14% which was unequal to the high cost of cell production. A change in this situation was brought about by Exxon Corporation in the 1970s which built a resourceful solar panel that appeared to be low maintenance. This was yet another important landmark in the evolution of solar technology.
Many indigenous, but all equally important breakthroughs started coming about, for instance, the opening of the Solar Energy Research Institute in the USA in 1977. Paul Macready in 1981 built the first aircraft driven by solar energy. Almost 1600 cells were laid on its wings and the airliner flew from France to England successfully.
In the following year Australia designed the first solar run cars. 1999 saw the development of the largest (so far) solar power plant yielding more than 20 kilowatts. The same year also saw yet another breakthrough in the form of a solar cell with an almost revolutionary 36% photovoltaic effectiveness.
With the gradual lowering of the cost of solar cells, they have emerged as the cheapest power source for moderate electrical demands built away from utility lines that are placed underground.
The global financial meltdown of 2008 had negative repercussions on the solar industry when many countries, particularly Spain cheapened grants on continuing production of solar energy. Lack of publicity and marketing also saw the failure of some prominent solar companies.
However, the last few years have witnessed a vast investment in beneficial solar plants. Recently in 2012, the biggest recorded solar energy plant was constructed in China called the Golmud Solar Park and has an invested facility of 200 megawatts. But the Gujarat Solar Park in India is said to have exceeded its Chinese counterpart with an assemblage of solar plants distributed in the Gujarat state, displaying a collective invested capacity of 605 megawatts.
Thus, with solar energy, the world can boast of not only a pollution free eco-system but also a future that is safeguarded against global warming and many other forms of environmental threats.