History of Solar Energy

Solar energy has been used by humans for thousands of years.  For example, ancient cultures used energy from the sun to keep warm by starting fires with it.  They also kept their homes warm through passive solar energy designs.  Buildings were designed so that walls and floors collected solar heat during the day that was released at night to keep them warm.  If you have ever stood in the sun to get warm then you too have utilized solar thermal energy.

The discovery of photovoltaics happened in 1839 when the French physicist Edmond Becquerel first showed photovoltaic activity.  Edmond had found that electrical current in certain materials could be increased when exposed to light.  66 years later, in 1905, we gained an understanding of Edmonds' work when the famous physicist Albert Einstein clearly described the photoelectric effect, the principle on which photovoltaics are based.  In 1921 Einstein received the Nobel Prize for his theories on the photoelectric effect.
Solar cells of practical use have been available since the mid 1950’s when AT&T Labs first developed 6% efficient silicon solar cells.  By 1960 Hoffman Electronics increased commercial solar cell efficiencies to as much as 14% and today researchers have developed cells with more than 20% efficiencies.  20% efficient means that out of the total energy that hits the surface of a solar cell, about 20% is converted into usable electricity.
The first long-term practical application of PV cells was in satellite systems.  In 1958 the Vanguard I, was launched into space.  It was the first orbiting vehicle to be powered by solar energy.  Photovoltaic silicon solar cells provided the electrical power to the satellite until 1964 when the system was shut down.  The solar power system was so successful that PV’s have been a part of world-wide satellite space programs ever since.  The sun provides endless nonpolluting energy to the satellite power systems and demand for solar cells has risen as a result of the telecommunications revolution and need for satellites.
The energy crisis and oil embargos of the 1970’s made many nations aware of their dependency on controlled non-renewable energy sources and this fueled exploration of alternative energy sources.  This included further research into renewable sources such as solar power, wind power and geothermal power.
An economic breakthrough occurred in the 1970's when Dr. Elliot Berman was able to design a less expensive solar cell bringing the price down from $100 per watt to $20 per watt.  This huge cost savings opened up a large number of applications that were not considered before because of high costs.  These applications included railroads, lighthouses, off-shore oil rigs, buoys, and remote homes.  For some countries and many applications, solar energy is now considered a primary energy source, not an alternative.