Throughout history, solar energy has always been present in the life of the planet. This source of energy has always been essential for the development of life. Over time, humanity has been improving the strategies for its use.
The Sun is essential for the existence of life on the planet: it is responsible for the water cycle, photosynthesis, etc. The first civilizations were already aware of this and, as civilizations have evolved, so have the techniques for harnessing its energy.
Initially, these were techniques to harness passive solar energy. Later, techniques were developed to harness thermal solar energy from the sun's rays. Later, photovoltaic solar energy was added to obtain electrical energy.
Importance of the Sun for ancient civilizations
The Sun has always been an essential element for the development of life. The most primitive cultures have been taking advantage of it indirectly and without being aware of it.
Examples of these civilizations can be found in Greece, Egypt, the Inca Empire, Mesopotamia, the Aztec Empire, etc.
Introducing the use of passive solar energy
The Greeks were the first to use passive solar energy in a conscious way.
From around 400 BC, the Greeks began to build their houses with the sun's rays in mind. These were the beginnings of bioclimatic architecture.
During the Roman Empire, glass was first used in windows to take advantage of the light and trap solar heat in homes. They even passed laws that made it a crime to block neighbours' access to light.
The Romans were the first to build glass houses or greenhouses. These constructions allowed the creation of suitable conditions for the growth of exotic plants or seeds brought from far away. These constructions are still used today.
Another way of harnessing solar energy was first developed by Archimedes. Among his military inventions, he developed a system for setting fire to enemy fleet ships using mirrors to concentrate solar radiation on one point.
This technique continued to be perfected. In 1792, Lavoisier created his “solar furnace” consisting of two powerful lenses that concentrated solar radiation into a focus. The concentration of solar radiation allowed high temperatures to be reached with which to melt metals.
In 1874, the Englishman Charles Wilson designed and managed a facility for the distillation of seawater in the Atacama Desert (Chile) for the Lastenia Salinas saltpeter plant. This solar power plant had the capacity to desalinate an average of 22,500 liters of water per day.
The first solar collectors: solar thermal energy
Solar thermal energy has a place in the history of solar energy since 1767. In this year, the Swiss scientist Horace Bénédict De Saussure invented the heliothermometer, an instrument with which solar radiation could be measured. The subsequent development of his invention gave rise to today's instruments for measuring solar radiation.
In 1865, French inventor Auguste Mouchout created the first machine that converted solar energy into mechanical energy. The mechanism involved generating steam using a solar collector and driving a motor using its pressure. Unfortunately, the high costs prevented his invention from being used commercially.
Mouchout was an important figure in French society. In addition to creating the first solar steam engine, he also came up with other inventions. Mouchout invented a solar cooker consisting of a black glass-covered container exposed to the sun. On the side of the container that was not exposed to the sun, he placed a parabolic cylindrical mirror to reflect solar radiation.
A solar-powered printing press was even invented, an invention that was conceived by Abel Pifre.
The first photovoltaic cells
In 1838, photovoltaic solar energy appears in the history of solar energy.
In 1838, French physicist Alexandre Edmond Becquerel first discovered the photovoltaic effect. Becquerel was experimenting with an electrolytic cell with platinum electrodes and noticed that when it was exposed to the sun, the electric current increased.
The next step was taken in 1873. The English electrical engineer Willoughby Smith discovered the photoelectric effect in solids, in this case selenium.
A few years later, in 1877, the Englishman William Grylls Adams, professor of Natural Philosophy at King's College London, together with his student Richard Evans Day, discovered that when selenium was exposed to light it generated electricity. In this way, they created the first selenium photovoltaic cell.
In 1953, Calvin Fuller, Gerald Pearson, and Daryl Chapin discovered the silicon solar cell. This cell produced enough electricity and was efficient enough to run small electrical devices.
Commercially available photovoltaic panels did not appear until 1956. At that time, the cost was still too high for most people. By about 1970, the price of photovoltaic solar panels had dropped by almost 80%.
Solar cells were used in US and Soviet satellites launched from the late 1950s onwards.
Temporary abandonment of the use of solar energy
With the advent of fossil fuels, solar energy lost importance. Solar technology was hampered by the low cost of coal and oil and the use of non-renewable energy sources.
The growth of the solar industry was high until the mid-1950s. At this time, the cost of extracting fossil fuels such as natural gas and coal was very low. Therefore, the use of fossil energy became very important as an energy source and for generating heat. Solar energy was then considered expensive and was abandoned for industrial purposes.
The resurgence of solar energy
During those years, the price of fossil fuels rose. This increase led to a resurgence in the use of solar energy for heating homes and water, as well as for generating electricity. Photovoltaic panels are especially useful for off-grid homes.
In addition to the price, gas and coal water heaters in homes were dangerous because poor combustion could generate toxic gases, carbon monoxide.
The first solar hot water heater was patented in 1891 by Clarence Kemp.
In this regard, Charles Greeley Abbott invented the solar water heater in 1936. His invention became popular at this time in Florida, California and other places in the USA.
The 1990 Gulf War further increased interest in solar energy as a viable alternative to oil.
Many countries have decided to promote this renewable resource by issuing decree laws to encourage its use, largely in an attempt to reverse the environmental problems arising from climate change.
Featured inventions by date and inventor
Here are some notable inventions in the history of solar energy, with their dates and inventors:
19th century: The first advances
- 1839 – Photovoltaic effect (Alexandre Edmond Becquerel): He discovered that certain materials generate electric current when exposed to light.
- 1866 – First solar engine (Auguste Mouchout) : He created a solar-powered steam engine, one of the first practical devices.
- 1883 – First selenium solar cell (Charles Fritts) : He built the first functional photovoltaic cell, although with an efficiency of only 1%.
20th Century: Development of modern solar energy
- 1905 – Explanation of the photoelectric effect (Albert Einstein): His work on the nature of light and the photoelectric effect laid the groundwork for the development of modern solar cells (Nobel Prize in 1921).
- 1954 – First silicon solar cell (Bell Labs: Daryl Chapin, Calvin Fuller and Gerald Pearson) : They created the first silicon photovoltaic cell with an efficiency of 6%, marking the beginning of commercial solar energy.
- 1958 – Use of solar energy in space (NASA, Vanguard I satellite): First satellite powered by solar panels, demonstrating the feasibility of solar energy in space.
21st Century: Recent Innovations
- 1994 – First solar cell with more than 30% efficiency (NREL, USA): Record efficiency was achieved with multi-junction cells.
- 2016 – Ultra-thin, flexible solar panels (MIT and other institutions) : Advances in materials allow the integration of solar cells on more surfaces.