Since the beginning humans have always used solar energy quickly learning of the Sun’s benefits to power their lives. Early on south facing caves in the northern hemisphere a practice that carried on for millennia as seen with the Anasazi in the Americas around 1200 AD.
Using the Sun’s power for more than heat started early too. In the 7th Century BC glassy materials were used to light fires and by the 3rd Century BC the Greeks and Romans used mirrors to ignite torches. The Romans continued the use of heat in sunrooms with massive windows to mimic the heat collection properties first seen in caves.
By the late 1700s the power of the sun was used in ovens on board ships to reduce the need to carry fuel and later used to heat water into steam to propel steamboats all as we entered the age of electricity.
Development Of Solar Generation
Like all modern technologies, electrical generation using solar energy was a series of sometimes hazy steps by many people. The French scientist Edmund Becquerel in 1839 created the first photovoltaic cell in his father’s laboratory showing light could cause electricity to be generated, although this was a curiosity rather than practical device.
Various people investigated the effect of light and electricity over the next few decades. In 1873 Willoughby Smith discovered the photoconductive potential of selenium, leading to William Adams’ and Richard Day’s confirmation in 1876 discovery that selenium does produce electricity when exposed to sunlight.
A decade after Willoughby Smith’s discovery in 1883, Charles Fritts produced the first working solar cells from selenium wafers, the start of the solar electrical age. However, the solar cells were not very effective, maybe 1 – 2% efficient, but electricity as part of everyday life was just beginning so electrical demand was not high. Over the next few decades research into harnessing solar energy and corresponding technologies before the breakthroughs that start the current solar age.
Over the succeeding years many people contributed to the progress of solar cells.
1887 Heinrich Hertz discovers the photoelectric effect.
1901 Philipp von Lenard observes how light frequency affects energy of electrons.
1904 Wilhelm Hallwachs builds a semiconductor-junction solar cell.
1916 Robert Millikan proves the photoelectric effect.
1918 Jan Czochralski develops a method to grow single crystals of metal later adapted to produce single-crystal silicon.
There have been many other patents and other recognitions awarded to many people for developments in advancement of solar technologies.
In 1954 at Bell Labs in the U.S., Daryl Chapin, Calvin Fuller, and Gerald Pearson created the first practical silicon based photovoltaic cell and with it the basis on which all modern solar energy is currently built. The cell was only 4% efficient, compared to today’s low to mid 20 % efficiencies, but the cell could power an electrical device for a few hours in a day.
The Space Age
The modern solar energy age was spurred on by the space race between the U.S. and Russia, quickly energising development of the technology. In 1958 four satellites were launched – Vanguard I, Vanguard II, Explorer III and Sputnik 3, all with solar cells powering some of the electronics on board. It was still early days, the 100cm2 solar panel on Vanguard I could only produce 0.1 Watt, but conversion efficiency had grown to 8%.
Solar energy development was accelerating. Hoffman Electronics by 1960 had improved conversion efficiency to 14%. In 1964 NASA launched the first Nimbus satellite with a 470 Watt solar array and in 1966 NASA launched the first OAO (Orbiting Astronomical Observatory) with a 1 kW solar array.
In 1973 the first solar building ‘Solar One’ was constructed by the University of Delaware using a combination of PV and thermal systems. Interestingly it was built using the BIPV principles of integrating solar cells into the roof tiles, something that we are returning to today with solar roofs.
Modern Developments
Jimmy Carter installed solar panels at the White House in 1979 when he was President, only to be removed by President Reagan in 1981. President Obama re-installed solar panels and a solar thermal system in his first term in the early 2010s.
In 1981 Solar Challenger, the first aircraft running on solar power, used 16,128 solar cells powering two 3 HP motors to fly 163 miles across the English Channel from north of Paris, France to the Manston, Kent in the U.K., taking 5 hours and 23 minutes.
Conversion efficiency leapt forward again to 20% in 1985 with silicon cell progress at the University of South Wales. Solar energy progress continued over the next decade reaching 33% efficiency in 1999 by SpectroLab working with the US National Renewable Energy Laboratory. This record remained until 2016 when the University of South Wales broke the record again in reaching 34.5% efficiency.
Today
In all this time the one major trend has been the decreasing cost of solar power. Back in 1956 one Watt of solar energy cost $300. By 1976 this had become around $100 per Watt as seen in the chart below. From there the price of solar cells plummeted by 99.6% until 2019 when the price reached price is less than $0.50 a watt.
The rate of decrease had a knock on effect on the price of electricity, the 2010s saw an 89% drop in the price of solar electricity as shown below between 2009 and 2019.
These combined effects has made solar one of the cheapest sources of energy available today, not only to the large power generators but also homeowners and business where the price made it impractical before. Today is an ideal time for everyone to take control of their energy and reduce or even eliminate the effects of external factors that have seen the price of electricity so volatile.