What is the history of solar energy and when were solar panels invented?

While solar energy has found a dynamic and established role in today's clean energy economy, there is a long history behind photovoltaics (PV), which brought the concept of solar energy to life. With the cost of solar power falling in the last decade, it's not easy to forget that the switch to solar had a completely different meaning just 15 years ago. Let's go back a few centuries to the origins of solar PV and explore the history of solar power and silicon solar technology.


When was solar energy first used?

In theory, solar energy was used by humans as early as the 7th century BC. History has told us that humans used sunlight to make fires with magnifying supplies. Later, in the 3rd century BC, it was known that the Greeks and Romans used solar energy with mirrors to light torches for religious ceremonies. These mirrors became a normalized tool called "burning mirrors". Chinese civilization later documented that mirrors were used for the same purpose in 20 AD.

Another early use of solar energy that is still popular today was the concept of "sun rooms" in buildings. These sunrooms used large windows to direct sunlight into a single busy space. Typically located on the south-facing side of buildings, some of the iconic Roman baths were sun rooms. In the late 1200s, the ancestors of Pueblo Native Americans known as Anasazi settled themselves in south-facing cliff dwellings to catch the warmth of the sun during the cold winter months.

In the late 1700s and 1800s, researchers and scientists had success using sunlight to power furnaces over long journeys. They also harnessed the power of the sun to build solar-powered steamships. After all, it is clear that even thousands of years before the era of solar panels, the concept of manipulating the power of the sun was common practice.


When were solar panels invented?

The development of solar panel technology was an iterative development that received a number of contributions from various scientists. Naturally, there is some debate as to when exactly they were created and to whom the invention should be attributed. Some people argue that the solar cell owes its invention to French scientist Edmond Becquerel, who determined that light can increase electricity production when two metal electrodes are placed in a conductive solution. This breakthrough, defined as the "photovoltaic effect", was also influential in later PV developments with the element selenium.

In 1873, Willoughby Smith discovered that selenium has photoconductive potential, and this led William Grylls Adams and Richard Evans Day to discover in 1876 that selenium produces electricity when exposed to sunlight. A few years later, in 1883, Charles Fritts actually produced the first solar cells made from selenium sheets – which is why some historians associate Fritts with the actual invention of solar cells.

But the solar cells we know today are made of silicon, not selenium. As such, some speculate that the true invention of solar panels is due to Daryl Chapin, Calvin Fuller, and Gerald Pearson creating the silicon photovoltaic (PV) cell at Bell Labs in 1954. Many argue that this event is the true invention of PV technology. because it was the first example of solar technology that could actually power an electrical device for several hours a day. The first silicon solar cell was able to convert sunlight into energy with an efficiency of four percent, less than a quarter of what modern ones can do.


Other important events in the history of solar energy

• Solar panels in outer space - Some of the earliest uses of solar technology were actually in space, where solar energy is used to power satellites. In 1958, the Vanguard I satellite used a small one-watt panel to power its radios. Later that year, the Vanguard II, Explorer III, and Sputnik-3 were launched with PV technology on board. In 1964 NASA was responsible for launching the first Nimbus spacecraft, a satellite capable of operating entirely on a 470-watt solar array. In 1966 NASA launched the world's first Orbiting Astronomical Observatory powered by a one kilowatt array.

• First solar residence - In 1973, the University of Delaware was responsible for constructing the first solar building called “Solar One”. The system worked on a hybrid solar and solar PV power source. It was also the first example of building integrated photovoltaic (BIPV) - it didn't use array solar panels, but instead integrated solar power into the roof, similar to the design of Tesla's new rooftop product.

• Achievements in solar conversion efficiency – Between 1957 and 1960 Hoffman Electronics made a series of breakthroughs in photovoltaic efficiency, raising the efficiency record from 8% to 14%. it was. The next major achievement was the University of South Wales achieving 20% ​​efficiency for silicon cells in 1985. In 1999, the National Renewable Energy Laboratory, SpectroLab Inc. and to create a solar cell with 33.3% efficiency. The University of South Wales broke that record again in 2016, when researchers achieved 34.5% efficiency.

• Solar powered airplanes – In 1981 Paul MacCready built the Solar Challenger, the first solar powered airplane, and flew with it across the English Channel from France to England. In 1998, the remote-controlled solar airplane “Pathfinder” set an altitude of 80,000 The record was broken after reaching the feet. Later, NASA broke this record in 2001 when they reached 96,000 feet with their rocket-free aircraft. In 2016, Bertrand Piccard completed its first zero-emissions flight around the world with the Solar Impulse 2, which today is the world's largest and most powerful solar powered aircraft.

• Solar-powered presidencies - In 1979, President Jimmy Carter had solar panels installed in the White House during his presidency. However, in 1981 President Ronald Reagan ordered the removal of the White House solar panels. In 2010, President Barack Obama requested that solar panels and a solar water heater be installed in the White House. Both were established during Obama's first term.

• Solar cost over time – Prices for solar panels have fallen significantly over the past few decades, leading to a surge in consumer demand in the US in early 2016 that required more than one million installations. In 1956, solar panels cost about $300 per watt. . By 1975, that figure had dropped to just over $100 per watt. Today, the cost of a solar panel can go as low as 0.50 watts. Consider this: Solar panel prices have dropped at least 10 percent each year since 1980. The falling cost of solar energy is largely responsible for the growing popularity of solar energy and the validity of PV as a reliable source of energy in today's world.