The history of solar power goes further back than you might think. This timeline covers key events in the history of solar energy since the photovoltaic effect was first observed in 1839 through to the present day.
Timeline of Events
1839 – Photovoltaic Effect Discovered
In 1839, Edmond Becquerel observed the photovoltaic effect for the first time. Only 19 at the time, this young French physicist created the world’s first photovoltaic cell as part of an experiment in his father’s laboratory in Paris, France.
Becquerel made his discovery after exposing silver chloride coated platinum electrodes to sunlight. During this process, he noticed how voltage and current were generated. As a result of his discovery, some people refer to the photovoltaic effect as the ‘Becquerel effect’.
1873 – Photoconductivity Discovered in Selenium
In 1873, Willoughby Smith, an electrical engineer from England, made an accidental discovery. Smith had developed a method for continually testing underwater cables as they were being laid. For his test circuit, he chose selenium rods to act as a semi-conductive yet high resistance material. However, when everything was set up, Smith experienced results that were inconsistent with his expected outcome.
Smith later discovered during a lab experiment how the conductivity of his selenium rods increased when exposed to sunlight. He, therefore, discovered the photoconductivity of the element Selenium. This key event in the history of solar power would later lead to the invention of selenium-based solar cells.
1876 – Electricity Produced From Light
In 1876, William Grylls Adams and Richard Evans Day became the first to demonstrate that they could convert sunlight into electricity without the help of moving parts. They did this by illuminating a junction between selenium and platinum which results in the photoelectric effect – and produces electricity.
This discovery was made only three years after Willoughby Smith discovered photoconductivity in selenium. It would pave the way for the invention of the modern solar cell.
1883 – The First Solar Cell Created
1883 saw the creation of the world’s first electricity generating solar cell. The American inventor Charles Fritts is credited with the invention. His solar cell would consist of selenium placed on a thin layer of gold. Whilst this cell had less than 1% efficiency, it was a milestone in the history of solar energy.
1888 to 1891 – Degradation of Solar Cells Observed
Sometime between 1888 and 1891, Alexander Grigorievich Stoletov was the first to observe the degradation of solar cells over time. This was a key event and led to the understanding that solar cells have a lifespan. Although less of a concern in today’s solar panels, the degradation/fatigue of solar cells is still an important factor that should be taken into consideration.
1905 – Albert Einstein Publishes Paper On The Quantum Theory of Light
In 1905, Albert Einstein published a paper on the quantum theory of light. In the paper, he explains his theory that light exists as tiny particles called ‘photons’ and how these particles can liberate electrons on a conductive surface.
Einstein’s theory offers one explanation for the photovoltaic effect first observed back in 1839. In 1921, Einstein was awarded the Nobel Prize in Physics for his work on the photoelectric effect.
1914 – Photoelectric Effect Proved
In 1914, the American experimental physicist Robert Andrews Millikan proved Einstein’s theory that photons can liberate electrons on a metal surface. Millikan was initially convinced that Einstein’s theory was incorrect until he set out to prove it wrong. After a decade long experiment, he was able to confirm Einstein’s theory in every detail.
1915 – Czochralski Process Discovery
1915 saw Jan Czochralski discover the Czochralski process. He made this discovery by accident whilst studying the crystallization rate of various metals. His accidental discovery involved him dipping his pen into molten tin rather than his inkwell. He then drew a tin filament which was later proved to be a single crystal.
Today, single crystal, or ‘monocrystalline silicon’ (mono-Si), is grown by the Czochralski process. Whilst Czochralski ‘s discovery in 1915 had no relevance for the solar energy industry at the time, his process would later become a key step in the production of mono-Si photovoltaic cells.
1932 – Photovoltaic Effect Discovered in Cadmium Selenide
During 1932, Audobert and Stora discover the photovoltaic effect in Cadmium selenide (CdSe). This photovoltaic material is still used in many of today’s thin-film solar panels.
1954 – First Practical Silicon Solar Cell Invented
On April 25, 1954, the industrial research and scientific development company Bell Labs announced the invention of the world’s first practical silicon solar cell. In contrast to earlier solar cell designs, the Bell Labs prototype was capable of an impressive 6% efficiency.
This event is considered by many to be the birth of photovoltaics. It is from this point that the solar energy industry took off with countless improvements in technology over the coming years.
1958 – Solar Cells In Space
1958 saw the launch of the first satellite to use solar cells for its power source. The Vanguard 1 was a small Earth-orbiting satellite designed to test the launch capabilities of a three-stage launch vehicle. It featured a single 0.1W, 100 cm² solar panel. The Vanguard 1 was also designed to test the effects of the environment on a satellite and its internal systems whilst in orbit around the Earth.
1959 – Solar Cells Reach 10% Efficiency
In the year 1959, Hoffman Electronics creates a commercial solar cell offering an impressive 10% efficiency. This product improves on their earlier attempts of 8% and 9% in 1957 and 1958 respectively. Shortly after, in 1960, Hoffman Electronics would announce a solar cell with an even more impressive 14% efficiency.
1963 – First Viable Silicon Solar Panel
In 1963, the Sharp Corporation was the first company to release a commercially viable silicon solar panel. Whilst Bell Labs had invented the silicon solar cell back in 1954, the Sharp Corporation was the first to release a viable module of silicon cells in a single photovoltaic panel.
1968 – The First Solar Powered Wristwatch
In 1968, the American inventor Roger William Riehl invented the world’s first solar-powered wristwatch. Named the “Synchronar”, his watch became
production-ready four years later in 1972.
1974 – Florida Solar Energy Center Opens
1974 saw the opening of the Florida Solar Energy Center, or FSEC for short. FSEC is a research institute owned by the University of Central Florida. It was the first state-supported renewable energy organization to be opened and is still the largest and most active of its kind in the United States today.
1977 – Global Solar Power Production Exceeds 500 kW
In 1977, the global solar energy industry reached a milestone of 500 kW production capacity. Whilst this is much lower than today’s capacity, it is seen by many as a baseline for measuring the adoption of solar power worldwide.
1978 – The First Solar Powered Calculators
Yes, most of us have used one at some point in our lives – solar powered calculators. The first models were invented in 1978 and quickly became the must-have accessory for students right around the world.
1982 – Mass Produced Polysilicon Solar Cells
Kyocera Corp became the first company to mass-produce polysilicon solar cells in 1982. Also known as ‘multicrystalline silicon’, polysilicon is the most popular photovoltaic material in use today. This is mainly due to a more efficient manufacturing process than monocrystalline silicon. Polysilicon is made by setting molten silicon in casts whereas monocrystalline silicon crystals need to be grown using the Czochralski Process.
1985 – 20% Solar Cell Efficiency Reached
1985 saw a breakthrough in solar panel efficiency. Australia’s University of New South Wales developed a solar cell with an impressive 20% efficiency.
1991 – National Renewable Energy Laboratory (NREL) Founded
In the year 1991, the US Department of Energy formed the National Renewable Energy Laboratory. Operated by the Alliance for Sustainable Energy, NREL is responsible for helping to transform the way in which both the United States and the world use energy. NREL would later establish a Solar Energy Research Facility in 1993.
1999 – Worldwide Solar Power Capacity Reaches 1000 MW
1999 saw a breakthrough in global solar power capacity. Worldwide, there was over 1000 MW of installed photovoltaic power. We can attribute this to previous technological enhancements helping to reduce the cost of solar PV systems.
2006 – 40% Solar Cell Efficiency Reached
In 2006, the worlds first solar cell to achieve a conversion efficiency of 40% was invented by Spectrolab Inc. – a wholly owned subsidiary of Boeing. You can read more about this breakthrough here.
2009 to 2010 – Global Solar Energy Capacity Skyrockets
Between 2009 and 2010, global solar energy capacity nearly doubled. According to renewable energy statistics released by IRENA, 2009 saw a global capacity of 40,327 MW which jumps to 71,309 MW in 2010.
2011 – Chinese Manufacturing Helps To Reduce The Cost of Solar
Throughout 2011, the fast-growing solar energy industry in China helps to reduce the cost of solar. This makes photovoltaic systems more affordable and helps to boost installations worldwide in the coming years.
2013 – Worldwide Solar Energy Capacity Reaches 137,889 MW
The recent boom in solar technologies continues, jumping from 99,539 MW in 2012 to 137,889 MW in 2013. This figure more than doubles over the next three years, reaching 297,019 MW in 2016.
2017 – Worldwide Solar Energy Capacity Reaches 389,572 MW
2017 was a significant year for the solar energy industry. Global capacity increases by nearly a third to 389,572 MW. This growth mainly came from Asia, particularly China who increased their solar energy capacity from 77,569 MW the year before to 130,646 MW in 2017.
Whilst there have been fewer breakthroughs in recent years, solar technologies have seen a surge in popularity across the globe. This shows that solar is a key player in how we generate electricity and will continue to be for years to come.