Solar energy, among its other renewable energy cousins, has taken off over the past ten years, with the US solar industry growing by 40% per year over the last decade. Worldwide solar capacity surpassed 500 GW in 2020, and it’s projected to surpass 1TW in just a few years. With solar energy becoming increasingly prevalent in our lives, it’s important to learn the history behind its development. So, when was the solar panel invented? And by whom?
Solar panels are the result of centuries of research in electrical engineering, chemistry, and physics. The first modern solar panel was developed by scientists at Bell Labs in 1954. Previously, inventor Charles Fritts created the world’s first rooftop solar array in 1883, but the solar cell efficiency was so low that it wasn’t practical.
Solar Power In Antiquity
Humans have always recognized the power of the sun, and even early humans found ways to capture the sun’s energy and use it for their benefit. The earliest known use of solar power was in the 7th century BC, when humans used magnifying glasses to concentrate the sun’s rays to start fires. Later on, the Greeks and Romans used concentrating mirrors to light torches. The Greek’s even had an experimental “death ray,” which used concentrated sunlight to set fire to enemy ships.
Horace de Saussure created the first known solar collector in 1767. It consisted of a series of glass boxes placed inside one another. When exposed to direct sunlight, temperatures in the inner-most box would heat up to over 100 degrees Celcius. His invention was successfully used as a solar cooker by Sir John Herschel during his expedition to South Africa.
The Photovoltaic Effect
In 1839, French scientist Edmond Becquerel stumbled upon what would become the foundational principle for the solar cell. While experimenting in his father’s laboratory, Becquerel placed platinum electrodes coated with silver chloride in an acidic electrolyte solution. He noticed that when he shined a light on the electrolyte solution, the electric current was enhanced. Becquerel had just discovered the photovoltaic effect, a phenomenon where certain materials generate electricity when exposed to light.
Particle Physics and Technological Advancments
Throughout the late 1800s and early 1900s, research into the physics of light, as well as new technologies, helped build a foundation toward the development of solar-powered devices. Though the technology of the day meant these technologies were limited in their applications, the discoveries and experiments during this period created the building blocks for the modern solar panels of today.
In the 1860s and 70s, the French government funded the development of a steam engine that used concentrated solar power to generate electricity. The device was invented by French physicist Augustin Mouchot, and was considered to be the first solar-powered engine. Unfortunately for Mouchot, a decrease in the price of coal made solar energy less economical, and so the French government cut his funding.
In 1883, Charles Fritts discovered the photovoltaic properties of selenium coated with gold. Believing that he could produce substantial energy, he built and installed the first solar array in New York City. Unfortunately, the efficiency of his solar array was less than 1%. Also, the high cost of selenium meant his idea was too costly for practical use.
Discoveries about the nature of light followed during the Progressive Era, with the foundation of modern-day physics. Heinrich Hertz described the photoelectric effect in 1887 when he observed that electrons were emitted by certain materials when exposed to specific frequencies of light. Albert Einstien expanded on this theory with the theory of relativity in 1905. He argued that light was actually made of particles, and not a continuous wave of energy, a concept that changed the face of physics.
The First Solar Panels
In the 1950s, Bell Laboratories began the development of a photovoltaic semiconductor used to generate electricity. Daryl Chapin, an engineer with Bell Labs, was searching for a way to power telephones in humid climates, where dry batteries degraded quickly. At first, he used selenium semiconductors, knowing the material had photoelectric properties, but the efficiency was too low. At the same time, scientists Calvin Fuller and Gerald Pearson were experimenting with different semiconductors. They found that silicon showed strong photovoltaic potential, which could be augmented by adding impurities. Being close colleagues of Chapin, they forwarded their findings and began developing a PV device with silicon semiconductors.
In 1954, they unveiled the first modern solar panel, using silicon wafers as semiconductors. They were able to achieve an efficiency of 6% and demonstrated their ability to generate electricity by powering a toy Ferris wheel and a radio transmitter. A few years later at Bell Labs, Egyptian engineer Mohammad Atalla found that coating the surface of silicon semiconductors to increase passivity greatly increased efficiency and durability. This set the stage for the first practical application of PV; space travel.
The Space Race
The US launched the Vanguard satellite in 1958, which was equipped with solar cells as a secondary energy source. This became the first prominent use of the solar cell. A year later, NASA launched the Explorer 6, which featured large wing-shaped solar arrays. This became the standard for space-based solar, and by the 1960s, almost every spacecraft was outfitted with similar solar arrays.
The increasing pace of the Space Race spurred the development of better solar cells. At the time, outer space was the only environment where solar panels were economical, as other forms of power in outer space were costly. Weight matters a lot when traveling to space, and solar panels provided adequate power in a lightweight package.
Growth of Solar Energy
While solar panels were thriving in the realm of space flight, they had yet to become economical for terrestrial use. Passive heating and concentrated solar were viewed as more practical options. The Simms Building, the first building which incorporated solar heating, was built in New Mexico in 1954. The first concentrated solar plant was designed and built in Italy by Giovanni Francia in 1968. It consisted of an array of solar collectors aimed at a central receiver and had a power output of 1 MW.
At the same time, electrical engineers and chemists were hard at work finding ways to advance PV technology. They made incremental gains in efficiency. Where the maximum efficiency was 8% in 1957, it had risen to over 14% in 1960. New semiconductor materials were being tested, and scientists experimented with different architectures for silicon PV modules to achieve more durable cells. Manufacturing techniques were also perfected, with the Sharpe Corporation producing commercially viable silicon PV cells by 1963.
The 70s and 80s saw an explosion in research and development towards solar, with governments and corporations around the world beginning to pour serious money into PV research. In 1970, Exxon Mobil funded the development of a significantly cheaper solar cell, which decreased costs by 80%. In 1977, the US Dept of Energy created the Solar Energy Research Institute, which later became the National Renewable Energy Laboratory. In 1982, the first large-scale PV solar farm went online in California, with a power capacity of 1 MW.
Solar research continued throughout the 80s and 90s, but PV was still considered a fringe form of energy. It was said that solar power would never become a practical form of energy, even though the solar industry had achieved $250 million in revenue by the early 80s. The solar industry steadily grew throughout the decades, and by 1999, worldwide solar capacity had surpassed 1 GW.
The increasing threat posed by climate change, and the realization that fossil fuels were running out, spurred more research in solar energy. It was taken more seriously as a potential form of energy by the general public. Solar farms started sprouting up, and solar panels became more common in small-scale uses as well. Solar-powered lights and handheld devices became household objects, and residential solar installation grew into a booming industry.
The Modern Era
Today, solar panels are everywhere; houses, buildings, solar farms, almost everywhere you look. The residential solar industry is booming as people look for ways to make their homes carbon neutral. Businesses and corporations are doing the same, helping to make their operations greener while cutting costs on electricity. Countries across the world are building massive solar farms in an attempt to reduce fossil fuel use. Even with the exponential growth of the solar industry, only about 4% of our worldwide electricity consumption comes from solar.
Someone shopping for solar panels today would find that they have a ton of options. Mono-Si or poly-Si, rigid or thin-film, LG or Panasonic; the choices are endless. The best panels have efficiencies over 20%, which allows for smaller arrays that produce more energy. Some solar panels are so efficient that they even work well in diffuse sunlight. Then there are bifacial solar panels that can collect sunlight on both sides.
Government incentives have helped spur the growth of the solar industry over the past two decades. The US, Europe, and Australia have all created laws and regulations that allow owners of PV systems to be reimbursed for the energy they produce. They might also get tax rebates that cover a part of the initial cost. The creation of a class of people who produce their own energy and sell it to utilities has revolutionized the way electricity is generated and consumed.
As solar panel research pushes into the future, PV technology is getting better by the day. Organizations like NASA and the NREL are developing high-tech panels with over 40% efficiency. Thin-film panels are becoming more powerful, allowing solar arrays to become effectively invisible and take up less space. Travelers can pick up a solar panel for a few hundred dollars and power their electronics while living off the grid.
The first solar panels can be traced back to Charles Fritts’ rooftop array in 1883, but they were so inefficient that they served no practical function. It wasn’t until the 1950s that we saw the first modern PV panel produced by Bell Labs. In the beginning, solar energy was only viable in outer space, where other forms of energy were too costly, but as research accelerated, solar crept its way into the common lexicon. The 2000s brought warnings of climate change and fossil fuel depletion, which spurred development in renewable energy. Today’s solar industry is huge, with countries like China and India building massive solar farms. But it’s not over. Solar still has a long way to go, and scientists are hard at work developing PV modules that are more efficient, and cheaper, to help make solar a stronger contender against fossil fuels.
Frequently Asked Questions
The first solar cell was developed by scientists at Bell Labs in 1954. They used the solar cell to power a small toy Ferris wheel and a radio transmitter. Inventor Charles Fritts had developed and installed a rooftop solar array in 1883, but it had an efficiency of just 1% and wasn’t practical for real-world applications.
The photovoltaic effect is a property of certain materials to generate an electric charge when exposed to light. It was discovered by French scientist Edmond Becquerel in 1839.
When solar panels were first developed, they were too expensive and impractical for terrestrial applications. At the same time, the Space Race was heating up, and traditional forms of energy were too cumbersome to use in the harsh environment of outer space. Hence, NASA engineers looked toward solar energy as a power source for their spacecraft.
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