There’s an energy source so powerful that it can potentially provide more energy in just one hour than the ENTIRE human civilization uses in a year. And that energy source has a virtually unlimited supply, lasting for BILLIONS of years. We’re talking about the Sun, and it’s going to be a major part of how we power modern life in the future. So, welcome to the first video of a new series that aims to explore the future of energy, beginning with Solar Power. (Dramatic Music Moment) Harnessing the power of the sun starts with the Photoelectric effect principle, which was first observed by Heinrich Hertz in 1887. The photoelectric effect is the phenomenon that occurs when light strikes certain materials, releasing a current of electrons. And that is fundamentally how solar or photovoltaic cells work. But the challenge that scientists have faced over the years has been improving the efficiency of energy harnessed from given amount sunlight. You see, when light strikes PV cells, most of the energy is lost by reflection or as heat. Take the first solar cell, created by Charles Fritts in 1883. It was made out of Selenium with a thin coating of gold and only converted between 1-2% of the sun’s energy. It wasn’t until the 1950’s that scientists at Bell Labs discovered that Silicon was more effective than Selenium. And this allowed for PV cells with 6% efficiency. But the cost of production at the time made them only practical for special uses such as on Spacecraft. From here, scientists were ready to face the 2nd challenge of lowering the cost of production. And this surprisingly brings us to the Exxon Corporation which funded research in the 1970s that led to PV cells being made from cheaper materials. This dropped the price of PV cells from $480 per watt all the way to almost $100 per watt adjusted for inflation. Today, most modern silicon solar panels are either mono crystalline or poly crystalline. Mono-crystalline PV cells are recognized by its dark color and trimmed corners. Each cell is a thin slice of a long cylinder of silicon. Then poly-crystalline have a blueish color and are made out of molten silicon poured into very thin films. The top commercial PV cells today have efficiencies of around 20%. On top of that, the cost per watt is expected to drop to just 22 cents by 2022! With the high efficiencies and low production costs, is Solar Power is now the fastest growing energy source, making up two-thirds of net new capacity globally. Global photovoltaic power capacity broke 1 GW for the first time in the year 2000. Today global PV power capacity is well over 500 GW accounting for around 1% of the world’s electricity generation. And according to a recent report out of Norway, the solar electricity generation will grow 65 times by 2050. There’s so much room for usage to grow as well as so much room for the technology to improve. Back in November, the Institute for Solar Energy Research in Hamelin, Germany developed a solar cell with an efficiency of 26.1%. This was achieved using Surface Passivation. The technique involves two thin layers of oxidized and crystallized silicon called passivating contacts, that are sandwiched between the solar cell and its metal contact. The contacts add efficiency by healing broken atomic bonds on the silicon surface along with preventing electric charges from being trapped in the system.
Episode 1 — Solar Power