If you want to be pedantic, you could submit that solar energy was first discovered by very ancient bacteria. The sun has been the driving force for all life on Earth since the first microbes developed the capability for photosynthesis, around 2.3 billion years ago.
Ironically, this led to a devastating environmental disaster known as the Great Oxygenation Event, caused by the emission of oxygen gas as a byproduct of photosynthesis. While these first solar-powered organisms caused a mass extinction, solar power today might hold the key to preventing a planetary crisis.
The roots of solar power can be traced back to 1839.
It was at this time that a 19 year old French physicist, A.E. Becquerel, whose focus up to that point had been related to phosphorescence and luminescence, discovered the photovoltaic effect. He found that when gold or platinum plates were submerged in a solution, then exposed to uneven solar radiation, an electrical current was generated.
In 1839 Alexandre Edmond Becquerel discovered the photovoltaic effect which explains how electricity can be generated from sunlight. He claimed that “shining light on an electrode submerged in a conductive solution would create an electric current.” However, even after much research and development subsequent to the discovery, photovoltaic power continued to be very inefficient and solar cells were used mainly for the purposes of measuring light.
How did solar power get commercialized?
In 1883, American inventor Charles Fritz created the first working selenium solar cell.
In 1888, a scientist from Russia named Aleksandr Stoletov built and patented the first true solar cell. In 1891, Baltimore inventor Clarence Kemp patented the first commercial solar water heater.
In 1905 solar power was brought into the world’s spotlight when famed physicist Albert Einstein published a paper on the photoelectric effect and how light packets carry energy.
Further innovation would come in the wake of Einstein’s momentous discoveries regarding the underlying mechanisms of the photoelectric effect. This new knowledge enabled Bell Labs to produce the first modern solar cell in 1954. While this project pioneered solar energy technology as we know it today, it was terribly inefficient. It cost $250 to generate a mere 1 watt of electricity, compared to $2 – $3 per watt from coal plants of the time.
Solar cells at that stage were still suitable for use in space, and in 1958, the Vanguard 1 spacecraft used solar as a backup energy source. A year later, a solar cell was developed with 10% efficiency, but still saw little usage outside of spaceflight.