A Brief History of Solar Energy – I
The Sun. A medium-sized star that is 4.5 billion (4500 million) years old, with a diameter of 1.4 million kilometres, primarily composed of helium and hydrogen, and not particularly exceptional on a cosmic scale. Known as ‘sol’ in Latin, its boils at 15 million degrees Celsius, while the surface (photosphere) reaches about 5,500 degrees Celsius. It’s so vast that 1.3 million Earths could fit inside it. This interstellar fireball travels at an amazing speed of 27,000 km per hour around the Milky Way (although it still takes 230 million years to complete one orbit) and will continue this journey for another 4-odd billion years until it exhausts the hydrogen in its core. However, beyond these physical facts, what concerns all living things on our planet is that life as we know cannot exist without the Sun. The Sun is the sole source of energy on Earth; without it, there would be no liquid water or water cycle (hydropower), no wind patterns driven by temperature differences (wind energy), and crucially, no photosynthesis, which sustains carbon-based life and is the basis for the formation of fossil fuels. Let us remember that fossil fuels – namely oil, coal and natural gas- are composed of living things that lived, died and buried deep in the Earth’s crust over time with the help of millions of years of photosynthesis and nutrient cycling.
When considering solar energy today, the immediate association is often with panels adorning the rooftops of buildings. However, long before harnessing the Sun’s rays to generate electricity, humanity had discovered ways to utilise its light and heat. For instance, the history of using the Sun’s rays to heat buildings dates back 6,000 years. In ancient China, people constructed homes with entrances and exits facing south, allowing the low-angle winter sun to naturally warm the interiors. Similarly, in the first century BC, both Ancient Greek and Egyptian civilisations developed techniques to utilize the winter sun in this manner. The teachings of the renowned Greek philosopher Aristotle, who lived between 384-322 BC, were further refined in De Architectura by the famous Roman architect Vitruvius, laying the groundwork for a range of architectural approaches now known as ‘passive solar design’. (In a previous article, we introduced the Earthship design, which successfully implements passive solar design principles).
In addition to these, the concept of harvesting solar energy by focusing the sun’s rays on a single point was realized 2,700 years ago using lenses, a concept still employed in today’s solar energy systems. By the third century BC, Greek and Roman scientists had utilised mirrors to concentrate the sun’s rays, capable of igniting torches. In an unverified tale, it is rumoured that the renowned mathematician and engineer Archimedes (287-212 BC) employed a similar mirror system to set fire to the wooden ships of the Roman navy during the siege of Syracuse.
Throughout history, these technologies evolved and were refined. It wasn’t until Leonardo da Vinci’s time that further advancements occurred. After hundreds of years, da Vinci conceptualised a concave mirror capable of focusing the sun’s rays to heat water boilers and explored the potential of using such a device to weld copper pipes.
By the eighteenth century, elite Europeans seeking to enjoy tropical fruits within their own gardens devised a solution. They covered the southern facades of their homes with glass greenhouses, and used the heated air within these glass winter gardens to warm their homes. With the widespread use of transparent glass, the understanding of heat retention grew. In 1767, Swiss inventor Horace-Benedict de Saussure constructed what is recognised as the world’s first solar energy collector. De Saussure successfully used sun rays to boil water in a small box, placed inside a larger box, both coloured black and insulated with wooden cork, and covered with glass. Essentially, the concept of cooking with direct solar energy was realised. This notion continued to evolve over time, leading to the development of new methods and “cookers” that concentrate the sun’s rays to a single point by using reflectors -an approach that also remains largely unchanged and is still utilised today.
Operation principle of Saussure’s solar collectorThe renowned French chemist Lavoisier was instrumental in addressing this challenge. Utilising a device he constructed with two glass lenses of varying sizes, he achieved a remarkable feat: heating water in a boiler to temperatures reaching 1750 C degrees. With a conscientious approach to environmental concerns, Lavoisier demonstrated that he could fulfil his experimental heating requirements this way and his record remained unbroken for the subsequent century.
With the advent of the Industrial Revolution, the expansion of the iron and steel industry, and the widespread use of fossil fuels, efforts to harness the sun’s theoretically boundless and clean energy for diverse purposes gained momentum. Among the pioneers was the French inventor August Mouchot, born in 1825, who managed to devise the world’s inaugural solar steam engine after numerous experiments. Mouchot ardently believed that only solar energy could suffice for the burgeoning demands of industrialisation. Following his lead, scientists developed parabolic reflectors. For instance, Mouchot’s assistant, Abel Pifre, demonstrated in 1882 that a boiler heated by a reflector with a diameter of 3.5 metres could produce 300W of energy, capable of powering a printing press. Subsequently, systems operating on this principle were employed to address larger-scale energy needs. The world’s first solar thermal power plant, erected by American engineer Frank Shuman in Egypt, exemplified the scalability of such systems. Employing parabolic reflectors with a colossal diameter of 62 metres, the plant could generate approximately 40 kW of energy for five hours, enabling water pumping from the Nile River to adjacent agricultural lands at a staggering rate of 20,000 litres per minute.
These techniques, collectively known as solar thermal technology, entail the conversion of solar energy into heat energy (heating of water). In our country, solar thermal systems commonly used for hot water purposes also adhere to this fundamental principle. Nevertheless, continuous advancements in methodologies and materials have led to the development of significantly more efficient systems compared to their earlier iterations, rendering them accessible for individual household use worldwide. The pioneering scientists of the 18th and 19th centuries, who laid the groundwork for early solar technologies, would undoubtedly take joy in witnessing the widespread adoption of this technology across the globe.
The invention of Photovoltaic (PV) Energy Systems
The photovoltaic method, enabling the direct conversion of sunlight into electrical energy, stands as a pivotal advancement in solar technology.
At its core, this method relies on the photovoltaic effect, derived from the Greek words ‘phos’ meaning light and the electrical unit ‘volt’. This effect was initially discovered in 1839 by the French physicist Alexandre-Edmund Becquerel at the age of 19. While conducting experiments in his father’s laboratory, Becquerel observed that platinum electrodes connected to silver chloride in an acidic solution produced voltage when exposed to light. His prompt publication of this discovery laid the groundwork for subsequent advancements in the field. Becquerel also made notable contributions to photography, discovering in 1840 the light sensitivity of silver halide, a technique later utilised for capturing colour photographs in 1848.
In 1873, British electrical engineer Willoughby Smith made a significant breakthrough by discovering that the element selenium exhibited photosensitivity -its electrical conductivity increased upon exposure to light. Expanding upon this finding, William Grylls Adams and Richard Evans Day conducted experiments in 1876 that unequivocally demonstrated the generation of an electric current when light was directed onto selenium ingots.
However, the credit for inventing the first literal solar cell goes to the American inventor Charles Fritts. In 1883, Fritts constructed the world’s first functional PV cell using selenium, placing it between an iron plate on one side and a semi-permeable gold plate on the other. Although these early cells had a mere 1% efficiency, they laid the foundation for the solar panel industry, which is now witnessing some of the most significant engineering advancements. Fritts is also credited with pioneering the ‘panel’ arrangement by connecting multiple selenium units together on the roof of a building in New York.
The original selenium rods used by Willoughby Smith in his experiments.Meanwhile, it’s worth noting that Albert Einstein, the renowned physicist awarded the Nobel Prize in Physics in 1922 for his ground-breaking contributions to theoretical physics, earned this distinction not for his theories of general and special relativity, but for his seminal 1904 paper on the discovery of the photoelectric effect (titled “On a Heuristic Viewpoint Concerning the Production and Transformation of Light“). Einstein’s explanation proposed that light could be defined as a stream of particles, with the energy of each particle being proportional to its frequency. According to his theory, when this beam is directed to a metal surface, the photons strike on the atoms and can dislodge electrons from the atoms if the frequency of the photons is sufficiently strong. This phenomenon, known as the photoelectric effect, results in the production of an electric current.
The true industrialisation of solar panels, however, didn’t come until the 1950s, following the aftermath of the Second World War. It was during this period that advances in PV theory, experimental research, and the granting of various patents laid the groundwork for significant progress. In 1954, American scientists Daryl Chapin, Calvin Fuller, and Gerald Pearson, working at the prestigious Bell Laboratories, achieved a major breakthrough by producing “solar cells” made from silicon transistors. These cells were capable of directly converting sunlight into electric current, thus powering standard electrical appliances. With an alleged efficiency of approximately 6%, these solar cells marked a significant advancement and were hailed as one of the greatest discoveries of the era. The New York Times heralded this achievement as “the beginning of a new era” that promised to harness the boundless energy of the sun for the betterment of civilisation.
By the end of the 1950s, advancements in solar cell efficiency continued, reaching up to 14%, largely due to the efforts of Hoffman Electronics. Despite the discovery of new light-sensitive materials such as gallium arsenide, the cost of solar cells remained prohibitively high (approximately $100 USD per watt of electricity produced), limiting their widespread adoption. Nonetheless, smaller devices incorporating solar cells began to make their way into everyday life.
One significant development of this period was the design, production, and launch of the Vanguard I satellite by the United States. Equipped with solar panels, Vanguard I showcased the potential of solar power in space exploration. The iconic image of satellites featuring two wings made of solar panels became synonymous with space exploration and remains ingrained in our collective consciousness as the quintessential satellite design.
During the 1960s, the proliferation of companies manufacturing selenium and silicon-based solar panels surged, particularly in the United States and Japan. In a milestone moment in 1962, Bell Laboratories launched the world’s first telecommunication satellite powered by solar energy into orbit.
The 1970s, notably impacted by the oil crisis in the USA, witnessed heightened investment in solar energy. Advancements in semiconductor materials and their increased utilisation in the industry led to a dramatic reduction in cell costs, plummeting from $100 to $20 per watt. These cells found applications in lighting and warning systems in areas beyond the reach of grid electricity. The establishment of the Institute of Energy Conservation at the University of Delaware in 1973 marked the inception of the first institution solely dedicated to PV technology research and development. The landmark construction known as “Solar One,” completed in the same year, etched its place in history as the first building to entirely fulfil its energy needs through solar energy (both PV and thermal), underscoring the burgeoning acceptance of solar energy viability across diverse sectors.
Although the PV industry experienced a slight slowdown in the 1980s with the decline in oil prices, both governmental bodies and private enterprises persisted in their support for solar energy research, incentives, and R&D endeavours. The mounting acknowledgment of the environmental pollution and climate change realities stemming from fossil fuel-based industries, which gained prominence in the 1970s, further bolstered support for PV technology that is heralded as a clean energy source. The 1980s witnessed notable milestones, including the production of the first aircraft powered solely by solar energy in 1981, the inauguration of the first megawatt-scale solar plant in 1982, and Australian Hans Tholstrup’s pioneering 4,500-kilometer journey in the world’s maiden solar car. It wasn’t until 1999 that global PV energy production surpassed the 1-gigawatt mark.
During the 1960s, the proliferation of companies manufacturing selenium and silicon-based solar panels surged, particularly in the United States and Japan. In a milestone moment in 1962, Bell Laboratories launched the world’s first telecommunication satellite powered by solar energy into orbit.
The 1970s, notably impacted by the oil crisis in the USA, witnessed heightened investment in solar energy. Advancements in semiconductor materials and their increased utilisation in the industry led to a dramatic reduction in cell costs, plummeting from $100 to $20 per watt. These cells found applications in lighting and warning systems in areas beyond the reach of grid electricity. The establishment of the Institute of Energy Conservation at the University of Delaware in 1973 marked the inception of the first institution solely dedicated to PV technology research and development. The landmark construction known as “Solar One,” completed in the same year, etched its place in history as the first building to entirely fulfil its energy needs through solar energy (both PV and thermal), underscoring the burgeoning acceptance of solar energy viability across diverse sectors.
Although the PV industry experienced a slight slowdown in the 1980s with the decline in oil prices, both governmental bodies and private enterprises persisted in their support for solar energy research, incentives, and R&D endeavours. The mounting acknowledgment of the environmental pollution and climate change realities stemming from fossil fuel-based industries, which gained prominence in the 1970s, further bolstered support for PV technology that is heralded as a clean energy source. The 1980s witnessed notable milestones, including the production of the first aircraft powered solely by solar energy in 1981, the inauguration of the first megawatt-scale solar plant in 1982, and Australian Hans Tholstrup’s pioneering 4,500-kilometer journey in the world’s maiden solar car. It wasn’t until 1999 that global PV energy production surpassed the 1-gigawatt mark.
Now, shifting our focus back to the early 1900s, a patent application filed in 1905 by inventor George Cove, born in Nova Scotia, Canada, offers insight into an early electricity generation method utilising the heat differential on a simple metal alloy (the patent was granted in 1906). Cove’s innovative approach involved harnessing heat from a wood stove to generate electricity, with evidence suggesting his utilisation of a similar technique in a series of solar panels to fulfil domestic energy requirements. An article published in The Technical World Magazine in 1909 described Cove’s electric generator as capable of storing a week’s worth of electricity for a household after just two sunny days. Priced at a modest $100, the generator was as robust as any kitchen appliance and enabled the utilisation of solar energy for various household applications such as lighting, food heating, or operating a sewing machine.
Cove’s invention, predating any other documented instance in history, demonstrates an early initiative in harnessing solar energy for electricity generation. It’s noteworthy, however, that Cove’s system relied on the established principle of “thermocoupling” rather than newly discovered materials like silicon or novel scientific principles. Thermocoupling, discovered by Thomas Seebeck in 1821, involves measuring temperature by connecting two different metal materials at two points and reading the voltage generated based on the temperature difference between the two.
Cove’s efforts to popularise this invention were unsuccessful. The reasons for this are unclear, because there was another person named George Cove living in the same place at that time and inconsistencies exist in the official records. However, by 1910, it became apparent that Cove’s efforts had faltered. In those days, he continued to work in his workshop in New York, seeking investors for his solar electric generator. According to a 19 October 1909 report in The New York Herald, Cove was reportedly abducted by unidentified individuals who demanded that he abandon his work in exchange for $25,000. Cove adamantly refused, and after his release, he accused Frederick W. Huestis, one of his investors, of orchestrating the abduction. Huestis denied the allegations, asserting that Cove fabricated the incident as a publicity stunt and that the electric generator was non-functional. Following this incident, Cove struggled to regain traction, ultimately leading to the closure of his company, Cove’s Sun Electric Generator Corporation.
But was Cove’s invention really functional? While experts examining the patent application agree that it is a viable method for electricity generation, doubts persist regarding its practical applicability. This is also thought to be the reason behind the remarks of Huestis. In a 1909 article in Engineering News, scepticism was expressed with the words “unless a new discovery is made in the methods of storing electricity, it is unlikely that any machine powered by the sun’s rays will achieve commercial success”.
One of George Cove’s first solar generatorsHowever, an alternative perspective posits that Cove’s machine did indeed function as intended. In this scenario, it’s conceivable that negative comments from Huestis were motivated by other persons seeking to thwart the advancement of solar electricity production and trying to suppress Cove’s innovation because of a conflict of interest. Do we have any idea who or what that might be? Do you remember the fate of Nikola Tesla?
The Edison Electric Illumination Company of New York, relying on coal and oil-based power plants for its extensive energy supply network, could have perceived the proliferation of solar power systems as a direct threat to its operations. Similarly, the Standard Oil Company, a dominant supplier of kerosene and petroleum products nationwide, may have viewed Cove’s invention unfavourably. Standard Oil’s interests in supplying petroleum products for use in power plants could have led to apprehensions about the disruptive impact of solar energy technologies on their market dominance.
There is no direct evidence linking Edison or Standard to any suspicious actions against Cove or his inventions. However, historical records do reveal the ruthless tactics employed by both entities against competitors perceived as threats to their interests. For instance, Edison infamously engaged in public demonstrations where stray dogs were electrocuted to discredit alternating current (AC) technology, which posed a challenge to his direct current (DC) system. Moreover, Edison’s covert purchase of AC electric generators from Westinghouse for use in prison executions, culminating in the world’s first electrically-induced capital punishment in 1890, further illustrates his aggressive approach towards competitors. As a result, the public eye began to associate AC with death.
Furthermore, it is documented that Edison extensively researched batteries for electricity storage between 1900 and 1914, primarily focusing on their application in automobiles. It is plausible that Edison’s preoccupation with automotive batteries may have diverted his attention from exploring the commercial potential of combining Cove’s solar energy systems with his battery technology for domestic use.
While little is known about George Cove’s personal life, historical records indicate his involvement in other inventions, including an electric generator powered by tidal movements in 1909, for which he received recognition from the Canadian government.
If Cove’s fate had taken a different turn, the trajectory of today’s solar technology and its global impact would have been uncertain. However, it remains a stark reality that without a swift transition away from fossil fuels towards renewable energy sources, we cannot avert the ecological and social devastation wrought by our contemporary lifestyles. The Jeavons’ Paradox, named after renowned British economist Jeavons, illustrates that enhancing the efficiency of energy supply and increasing the availability of usable energy inevitably leads to heightened consumption, driven by the resultant decrease in energy prices. Hence, it is evident that prioritising large-scale strategies that consider the well-being of all inhabitants of the planet, human and non-human alike, and emphasize efficiency through conservation should be embraced universally. It is imperative for societies to collectively embark on this path, taking concerted actions towards sustainability.
In the second part of our article, we will delve into recent advancements in solar energy, exploring its expanding application areas, emerging technologies, and offering insights into its future potential. Stay tuned for more updates![
REFERENCES
- 1. https://journals.lib.unb.ca/index.php/MCR/article/view/17744/22231
- 2. https://en.wikipedia.org/wiki/George_Cove
- 3. https://www.ecowatch.com/solar/solar-history
- 4. https://www.researchgate.net/publication/318410023_The_history_of_using_solar_energy
- 5. https://science.nasa.gov/sun/facts/
- 6. https://www1.eere.energy.gov/solar/pdfs/solar_timeline.pdf
- 7. https://www.smithsonianmag.com/sponsored/brief-history-solar-panels-180972006/
- 8. https://www.aps.org/publications/apsnews/200501/history.cfm
- 9. https://www.economist.com/science-and-technology/2018/02/03/a-new-type-of-solar-cell-is-coming-to-market
- 10. https://news.mit.edu/2022/perovskites-solar-cells-explained-0715