SOLAR LIGHTS UP THE CENTURIES
Solar power has been around since the Seventh Century BC.
In ancient Egypt, heat from the sun was used to bake a mixture of straw and mud into bricks which were used for construction.Ancient Greeks and Romans recognised the benefits of what we now call passive solar design – using architecture to maximise the sun’s capacity to heat and light indoor spaces.
Building south-facing houses enabled them to maximise the winter sun. Simultaneously, they were able to reduce their dependence on firewood which was often in short supply, making early use of renewable energy in preference to fossil fuels.The Romans took solar design seriously, making it illegal to obscure a neighbour’s access to sunlight and using glass for windows.
Much less passive was the use of solar energy by the Ancient Greeks, who used bronze shields to direct the sun’s rays onto the wooden ships of the Roman army to set fire to them. Some native American cultures built their homes against the sides of rocky cliffs to benefit from the natural storage of heat harnessed during the day.
It was not until 1839, nearly 80 years after a solar collector is said to have been built by Swiss scientist, Horace de Saussure, that the platform for modern solar energy development was established with the discovery of the photovoltaic effect by French physicist, Edmond Becquerel. He discovered that electric current in certain materials could be increased when exposed to light.
French scientists continued to experiment with solar power, with a notable achievement by Auguste Mouchout in developing the first active solar motor as well as a solar-powered steam engine.The high cost of production prevented both inventions from succeeding.
Around the globe, scientists were experimenting with solar energy.In the lae 1870s, William Grylls Adams worked out that when light was shone on selenium, it shed electrons, thereby creating electricity.
Albert Einstein, better known for his Theory of Relativity, was awarded the 1921 Nobel Prize in Physics for his theories on the photoelectric effect – involving the generation of electricity through solar cells.
In the 1950s, Bell Laboratories (now known as AT & T Laboratories) developed the first silicon solar cell which could generate a measurable electric current.This was the first time that a cell had been developed that could convert the sun’s energy to power everyday appliances.
The first practical application of photovoltaic silicon solar cells also came in the 1950s with the launch of the satellite, Vanguard 1.In 1981, an aircraft powered by 16 000 solar cells giving off 3 000 watts of power flew from France to England.
The Arab Oil Embargo in 1973/4 forced western economies to rethink solar energy research as a means of reducing their dependence on oil.In the 1970s, Dr Elliot Berman designed a less expensive solar cell, which enabled a large number of new uses to be considered, such as railroads, navigation warning lights and homes in remote areas.
Environmental concerns have also escalated the search for renewable energy resources such as solar power, wind power and geothermal power.And whilst technologies today are a far cry from baked mud and straw bricks, the basic idea of using solar energy as a viable source of renewable energy remains.
