Solar Energy Technology can be broken into two strands, namely solar Thermal and Solar Photovoltaic.
Solar Thermal Energy has been utilized by civilizations from time immemorial. Our ancestors in the northern hemisphere lived in caves, with their openings towards the south. This was done to allow most amount of light into the dwelling, particularly during cold winter days. In the northern hemisphere, the sun is found low on the sky, traversing mostly near the southern horizon during the winter.
Moving forward in history, we notice a mention of solar energy technology in the Romans Mythology. It has been recorded that during second Punic War, Archimedes built bronze mirrors that would concentrate sunlight and reflect it on Roman ships. This concentrated beam of solar radiation was enough to set the ships on fire. Although in theory it can be done, however many modern researches believe it is nothing but a myth as the technology to build concave mirrors with that level of accuracy did not exist in those days. More details can be found on this link
The first adverts for Solar Water heaters appeared in the form of posters in 1884, in Texas USA (climax solar water heaters). Solar Thermal technology went into a decline in the oil age, as our addiction to fossil fuels grew in the 20th century.
The environmental movement in the 60’s brought a renewed interest in this field. A great amount of work was carried out in Solar Thermal Technologies, particularly after oil-shock of the 70’s. The University of Wisconsin Madison became a centre of excellence in this field. It was during this time that even the Whitehouse embraced solar hot water systems.
However, Solar Thermal Technology particularly solar hot water systems suffered a setback as our addiction to oil continued to grow during the 80’s and the 90’s . However, since the Kyoto protocol, the technology has made a comeback. Today solar farms have mushroomed in many arid zones around the world. A great example of this are the PS10 and Ps20 solar thermal power plant, that have been powering Seville in Spain.
Furthermore, Solar Stirling dish systems have also surfaced as one of the most efficient electricity producing technologies. Stirling Engines which are an emission free and were almost confined to the shelves have found a new application coupled with solar technology.
In the early part of 20th century, studies on photovoltaic effect were published. Towards the middle of the century, the push towards electronics led to the development of first solar cell. In the era of space race, it became apparent that fossil fuels would not be able to power a satellite indefinitely. Therefore a new power source was required that could continuously work in space environment. Work on Solar cell was accelerated. The first cells had efficiency of only 1%. Today satellites carry cells that are more than 40% efficient (Multi-junction solar cells).
The research on solar cells has exploded in the last two decade. Work particularly on low cost thin film panels as well organic solar cells have attracted many commercial concerns. Roof tiles that act as solar panels, are available in the market. In the future, the whole walls and facades will comprise of solar panels if deemed feasible.
A variety of panels are available today. The market is dominated by single crystal silicon cells. However, recently huge inroads have been made by thin film solar cells and also compound solar cells. This will be explored later.
Many semi-conductor materials are being explored concurrently. Solar PV panels have achieved grid party in many parts of the world as the costs continue to decline.
It should be noted that bio-reactors that produce algae by capturing the sun are also being explored to capture carbon and avert climate change.
The video below captures the history of solar technology.
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