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History of Solar Energy, Part I

In this article, we’ll review the early history of solar energy.  It will become clear pretty quickly how ‘not-new’ the impulse to use the energy of the sun to make life easier. 

 
If we’re really going to talk about the history of solar energy and the impact it’s had, we have to go back to the beginning of life on this planet – at least to the point where plants began using photosynthesis to live. 

Photosynthesis is the earliest example of living things reaping direct benefit from the sun’s light.  I’m not going to go into huge detail here, but several billion years ago plants developed the ability to capture solar energy chemically and store that energy as food. 

 
It’s ironic, really, that one of the reasons I discussed in the first module for pursuing solar energy was that it makes good ecological, political and economic sense to move away from fossil fuels.  Ironic because fossil fuels are in actuality highly condensed, chemically captured solar energy!  Those photosynthetic plants from so far back in time deposited all that energy in a fashion that we can tap into today.  It’s just unfortunate that releasing that energy for our own purposes involves so many down sides. 

 
And, of course, none of that chemical capture was intentional.  Intentionally taking advantage of the energy the sun is spraying all over the planet had to wait almost 4 billion years until humans started catching on to some of the power offering itself to us. 

 
Even then, technological innovation went pretty slowly.  The U.S. Department of Energy has noted the following landmarks in the development of solar energy by humans:

7th Century B.C.

A magnifying glass is used to concentrate the sun's rays on a fuel and light a fire for light, warmth, and cooking.

3rd Century B.C.

Greeks and Romans use mirrors to light torches for religious purposes.

2nd Century B.C.

As early as 212 B.C., Greek scientist Archimedes makes use of the reflective properties of bronze shields to focus sunlight and set fire to Rome's wooden ships, which were besieging Syracuse. (Although there is no proof that this actually happened, the Greek navy recreated the experiment in 1973 and successfully set fire to a wooden boat 50 meters away.)

A.D. 20

The Chinese report using mirrors to light torches for religious purposes.

1st to 4th Century

In the first to the fourth centuries, Roman bath houses are built with large, south-facing windows to let in the sun's warmth. 

6th Century

Sunrooms on houses and public buildings are so common that the Justinian Code establishes "sun rights" to ensure that a building has access to the sun.

13th Century

In North America, the ancestors of Pueblo people known as Anasazi build south-facing cliff dwellings that capture the warmth of the winter sun.

 Source: http://www1.eere.energy.gov/solar/solar_time_7bc-1200ad.html

1767

Swiss scientist Horace de Saussure is credited with building the world's first solar collector, later used by Sir John Herschel to cook food during his South African expedition in the 1830s.

1816

On September 27, 1816, Robert Stirling applies for a patent for his economiser at the Chancery in Edinburgh, Scotland. A minister in the Church of Scotland until the age of 86, Stirling builds heat engines in his home workshop in his spare time! Lord Kelvin uses one of the working models in some of his university classes. This engine is later used in the dish/Stirling system, a solar thermal electric technology that concentrates the sun's thermal energy to produce electric power.

Source: http://www1.eere.energy.gov/solar/solar_time_1767-1800.html

 Observe that for about 2,600 years harvesting solar energy amounted to one thing: heating something up.   Humans could only burn chemically captured solar energy (wood or coal), position their homes to take advantage of the sun’s rays for warmth, or use mirrors or lenses to focus the suns heat for cooking or military purposes.  

Only in 1816 did anyone begin to look for ways to translate that energy into something other than pure heat – but even then the dish/Sterling system relied on focusing solar thermal energy and using that to create electricity (in much the same way electricity is created by burning coal today). 

 
Indeed, it wasn’t until 1839 that a discovery fundamentally how we can take direct advantage of the sun’s radiation. 

 
And we’ll talk more about that development and those of the almost two centuries following in the article "History of Solar, Part II".

Take care,

 Sullivan