What is the History of Solar Energy?

When most people think of solar power, they think of rooftop solar panels, also called photovoltaics, powering a home. However, solar power includes anything and everything that could be powered by the sun, from early humans lighting fires with shards of glass, to solar-powered rovers on the surface of Mars.

With this brief history of solar energy and the solar panel timeline, you’ll learn the amazing ways solar power has been used across centuries to benefit humanity.

The Early Days of Solar Energy

The history of solar power and harnessing of solar energy began with humans using it to create fires as early as the 7th century BCE. By holding clear pieces of glass over dry wood, early humans could focus the sunlight on a single point and thus kindle a flame.

A few centuries later, Romans and Greeks developed mirror technology that could harness solar power to light torches for ceremonies. If you've ever had light from the sun hit you after bouncing off a mirror, you know this can be an effective method of focusing that energy. These "burning mirrors" gained popularity, and the Chinese began using them around 20 CE.

Beyond its ability to kindle flame, people have used the sun to warm their houses for hundreds of years. Across centuries and cultures, we find "sunrooms" designed with massive windows to direct sunlight into a specific area. Some Roman bathhouses were built with windows facing the south to create such a sunroom. Over in the American Southwest, the Anasazi built houses on cliffs facing the south to help warm their homes during the winter.

Jumping forward: Those solar ovens you may have created in middle school science class? They were first developed in the late 1700s as a way to cook food during long voyages.

In the 1800s, people created solar-powered steamboats to aid water travel. The December 1, 1870 issue of The Technologist reports on Captain Ericcson’s attempts to use solar rays to produce motive power, though it was not intended to replace standard steamboats, and was only intended to be used in areas with increased sunshine.

The Science Behind Solar Power

These early methods of harnessing the energy of the sun likely fostered the technologies we see today, including the creation and continued development of solar panels. In fact, many people, projects, and research studies across centuries led to the invention of solar panels and the industry we now celebrate.

To understand the complete history of solar power and the technology behind solar panels, there are two main concepts you need to understand: the photoelectric effect and the photovoltaic effect. These two effects are the foundation of modern solar power.

Photoelectric Effect

The photoelectric effect occurs when a material or substance is exposed to electromagnetic radiation such as light, causing electrons in the material to be emitted as free particles.

When light hits a piece of metal, the electrons in the metal will absorb the energy and become excited, meaning the solar energy will increase the kinetic energy of the electrons. If the kinetic energy of the electron is great enough to overcome the binding energy of the atom, the electron will be released as a free particle.

You can visualize this by imagining a well with a marble circling around inside it. The marble represents an electron bound to an atom. When a light photon enters the well, it hits the marble/electron, giving it enough energy to shoot out of the well.

Photovoltaic Effect

The photovoltaic (PV) effect, like the photoelectric effect, occurs when a material or substance is exposed to light, causing electrons in the material to become excited. However, while the photoelectric effect results in particle emissions, the photovoltaic effect results in an electric current. This means that the electrons are not ejected but instead stay in the materials.

You can observe this effect in semiconductors or any materials with a conductivity level between a conductor and an insulator. When light hits a semiconductor, the electrons cannot leave the material like they do in the photoelectric effect.

Instead, when the electrons absorb energy, they enter an excited state. At this point, the electrons are freed so they can cross the barrier between two different substances. The end result is the creation of an electric current.

The Arrival of the Solar Panel

The discovery of the photoelectric and photovoltaic effects led to significant advances in the understanding and use of solar power. On the timeline of solar energy history, multiple scientists contributed theories that ultimately evolved into what we think of as the modern-day solar panel:

• 1839 - French scientist Alexandre-Edmond Becquerel created a photovoltaic cell, inspiring future developments in photovoltaics.
• 1873 - Willoughby Smith discovered the photovoltaic effect in selenium.
• 1883 - Charles Fritts developed a solar cell using selenium coated with gold.
• 1883 - John Ericsson created a “sun motor” to run a steam boiler using parabolic trough construction (PTC), a set of concave mirrors that concentrate solar rays on a receiver tube to convert sunlight into clean energy.
• 1884 - Charles Fritts installed solar panels on a New York City rooftop.
• 1888 - Wilhelm Hallwachs described the physics of photovoltaic cells. This became known as the Hallwachs Effect, which occurs when a negatively charged body in a vacuum is released after being exposed to ultraviolet radiation.
• 1905 - Albert Einstein explained how light can create an electric current by knocking electrons out of the atoms in certain metals. (Sound familiar? He’s describing the “Photoelectric Effect” that we mentioned above.)

Advances in Solar Energy Technology

Our look at solar energy history continues into the 20th and 21st centuries with ongoing advancements in solar panels. With multiple theories in hand that proved the potential of solar power, the history of solar panels includes the development of solar-powered devices that soon followed.

• 1912 - The Sun Power Company used parabolic trough construction (PTC) to build the world's first solar thermal power plant.
• 1916 - Jan Czochralski invented a method of creating single crystals of metal. This served as the basis for the semiconductor wafers that are still used today in electronics like solar cells.
• 1941 - Bell Laboratories engineer Russel Ohl filed a patent for the first monocrystalline silicon solar cell.
• 1951- The first solar cells made from germanium were constructed.
• 1954 - Bell Labs made the world’s first solar panel from silicon, though it was only 4% efficiency.
• 1947 - Passive solar houses grew in popularity because of an energy shortage after World War II, a trend that reimagined the “sunrooms” of antiquity.
• 1955 - 1960 - The first solar-powered telephone call was made; the first solar-powered radio was introduced, made, and sold by General Electric; and Vanguard I became the first spacecraft powered by solar panels.
• 1960 - Hoffman Electronics improved photovoltaics from 8-14 percent efficient.
• 1962 - 3,600 cells from Bell Laboratories powered Telstar, the first solar-powered communications satellite.
• 1967 - The USSR launched Soyuz 1, the first solar-powered spacecraft to carry humans.
• 1972 - The Synchronar 2100 solar-powered watch entered the market.
• 1970s - The United States government passed several pieces of legislation and created agencies to increase and regulate solar energy usage.
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• 1981 - The Solar Challenger became the world's first solar aircraft capable of flying long distances.
• 1982 - The first large-scale solar farm was built in California.
• 1985 - Lithium-ion batteries were developed.
• 1985 - The Centre for Photovoltaic Engineering at the University of New South Wales in Australia developed the first silicon cells to reach 20% efficiency.
• 1991 - Lithium-ion batteries entered commercial production.
• 1999 - NREL and SpectroLab Inc. created a solar cell with 32% efficiency.
• 2005 - The Federal Investment Tax Credit (ITC) was originally created by the Energy Policy Act of 2005
• 2008 - NREL achieved a world record when they reached 40.8% solar cell efficiency.
• 2015 - Tesla released the Powerwall battery pack, which allows rooftop solar owners to use solar battery storage to store electricity.
• 2015 - Google released Project Sunroof to help homeowners decide if rooftop home solar was feasible for their house.
• 2020 - Experts calculated that it’s less expensive to build a new solar plant than to continue operating an existing coal plant.
• 2020 - California required all newly built homes to include solar panels.

Notable Solar Power "Firsts" in Modern History

While solar power technology has been around for thousands of years, some of the most significant developments in the history of solar panels have occurred in recent years. Here are a few notable inventions of solar energy:

The Sunmobile

William G. Cobb invented the first solar-powered vehicle in 1955 while working for General Motors. The 15-inch-long vehicle was called the “Sunmobile” and displayed how the sun's rays can be converted into electricity when exposed to certain surfaces. The “Sunmobile” had twelve photoelectric cells made of selenium. When sunlight hit the cells, the electric current powered a tiny motor that turned the vehicle's driveshaft and was connected to the rear axle by a pulley.

Adventures in the Air

One of the most surprising solar energy history facts is that solar panels were put in outer space as early as 1958 when the Vanguard I satellite used a tiny one-watt panel to power its radios. Later that same year, the USSR launched Sputnik 3 with PV technology, while NASA launched Vanguard II in 1959 with improved solar technology. Throughout the rest of the ‘60s and ‘70s, NASA launched projects like Nimbus and Orbiting Astronomical Observatory (OAO 1) that were powered in part by solar panel technology.

Designed and built under Dr. Paul MacCready, the Solar Challenger was the first solar-powered plane capable of flying long distances. In 1981, it made a 163-mile flight over the English Channel from France to the U.K.

In 1998, a remote-controlled solar airplane dubbed Pathfinder Plus set an altitude record for propeller-driven aircraft when it reached 80,000 feet. That record for non-rocket aircraft was broken in 2001 by NASA when they hit 96,000 feet with its solar-electric Helios project. In 2016, the Solar Impulse 2, flown by Bertrand Piccard, completed the first flight around the world by a piloted fixed-wing aircraft using only solar power.

Domestic Developments

In 1973, the first completely solar-powered building, Solar One, was built in Delaware. The building operated on a hybrid supply of solar PV panels and solar thermal power. It also included the first example of building-integrated photovoltaics (BIPV), meaning it didn't use individual solar panels but rather had solar integrated into the rooftop itself.

Several government buildings have been partially or fully run by renewable resources. For example, President Jimmy Carter had a solar array installed on the White House in 1979, but President Ronald Reagan had them removed a few years later. During his first term in 2010, President Barack Obama had a solar panel system and a solar heater installed at the White House.

In 2016, Las Vegas, NV became the largest city government in America to be run entirely on renewable energy. Part of this energy comes from solar panel trees in front of the city hall.

In the last decade of the solar power history timeline, several U.S. cities have made the switch to generating electricity with solar and being powered by 100% renewable energy:

• Aspen, CO
• Greensburg, KS
• Burlington, VT
• Kodiak Island, AK
• Rock Port, MO
• Eugene, OR
• Georgetown, TX

Sierra Club reports that over 180 U.S. cities have committed to powering their communities with 100% renewable energy by 2035.

History of Solar Energy

The invention of solar energy is often thought of as a newer discovery, but this is not the case. Anything that uses the sun to create power is considered solar power. This means everything from using a magnifying glass to start a fire to using solar panels to power your home can be considered solar energy. Thus, exploring the history of solar energy will lead you on a fascinating chase across thousands of years of human ingenuity.

Several crucial discoveries around the photoelectric and photovoltaic effects in the 19th century launched the formal study of solar power as a source of electricity. Since then, many applications of solar power have been created, many of them focused on improving the overall efficiency of solar panels.

This process of rapid discovery can be easily compared to the growth of modern computing. If solar technologies keep growing at a similar rate, we expect to see huge discoveries in solar power over the next one hundred years.

If you’re ready to learn more about installing the right solar power system on your home, contact Palmetto today. You can even get started by using our free Estimate Your Savings Tool to see how you could lower your electricity bill.

About the AuthorCory O'BrienSenior Director - Growth Marketing

Cory brings over 8 years of solar expertise to Palmetto, and enjoys sharing that knowledge with others looking to improve their carbon footprint. A dog lover residing in Asheville, NC with his wife, Cory graduated from UCSB. If you run into him, ask him about the company he founded to rate and review beer!