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  • I have a very distinct memory of tv telling me, "every hour the sun beams enough solar

  • energy to power our planet for a year." Solar power, however, has yet to deliver on this

  • promise from my children's television. Why is it so hard????

  • The sun shines on us every day, it comes down here we gather it up and we use it for energy

  • -- boom boom boom, done! But it's slightly more complicated than that, as you know.

  • In 1873, electrical engineer Willoughby Smith discovered the element selenium was photoconductive

  • -- when exposed to sunlight the metallic form of selenium becomes a semiconductor! Three

  • years later, other scientists discovered selenium could be used to create electricity from sunlight

  • -- dubbed the photoelectric effect. When sunlight hits a metal like selenium the electromagnetic

  • radiation is absorbed into it -- this fueled a whole HOST of physics nerds who are still

  • arguing whether light is a particle or a wave to this day! It was such a big deal the 1921

  • Nobel Prize in physics was awarded to Albert Einstein for explaining the photoelectric

  • effect, and for his contributions to theoretical physicsor whatever.

  • Eventually, scientists discovered that the light energy causes the freeing of electrons

  • which, if captured, could be used to generate electricity!. This photoelectric effect has

  • since been cultivated and researched and cultivated again, and the discovery that many different

  • elements display a photoelectric effect opened it up for use in a number of inventions! Photosensitive

  • cells are used in televisions, industrial processes, telecommunications, fiber optics,

  • copy machines, spectroscopy and telescope, and to sense pollution or emphasize other

  • lights like in night vision or infrared cameras; plus, of course, solar panels via a photovoltaic

  • cell. Photovoltaics were invented in the 1950s, and were popularized by the space program

  • as a way to power satellites. In the 1970s, pushes were made to modernize photovoltaics

  • for use in commercial and residential power -- but consumers mainly used them for calculators,

  • watches, radios and the like. Like a battery, a photovoltaic cell has a positive and negative

  • to guide the electrons into the system. Each cell uses a pair of silicon wafers -- one

  • doped with phosphorous (negative) and one with boron (positive).

  • From 1995 to 2010 solar energy use grew 20 percent a year -- and now, new inventions

  • are making it even more affordable. Firstly, in 2009, China created way more solar panels

  • than the market needed, and the price collapsed. And secondly, state and federal governments

  • in the United States, Germany, the United Kingdom and Japan are all giving subsidies

  • to cultivate better renewable energy systems. This means more supply and demand for this

  • technology, and as money flows through renewables, they get better!

  • Recently the University of Queen Mary in London revealed they can turn shrimp shells into

  • cheap solar panels. The shells of crustaceans contain chitin and chitosan which can be extracted

  • into CQD or carbon quantum dots -- CQD solar cells aren't new, but usually use expensive

  • ruthenium for its photoelectric properties. Instead, the researchers found this biomass

  • byproduct of the shrimp industry can be used to extract CQDs and create fully renewable,

  • cheap solar cells!

  • Pretty cool, huh? Fortunately solar cells aren't the only place finding greener solutions

  • for energy use -- Toyota is, too! The new Toyota Mirai is looking to the future with

  • sustainability in mind; fueled by hydrogen and leaving zero emissions behind.

  • Every year renewable energy is getting better, but it's not yet as efficient as we'd hope.

  • For more on the efficiency of the most common types of energy production, check out my video

  • about that here

  • What do YOU think is the most promising type of energy? Solar? Wind? Nuclear? Or plain

  • old coal, oil and gas? Why? Tell me your thoughts in the comments, and thanks for watching.

  • If you haven't subscribed yet, go up there and subscribe. We need you here! Thanks again.

I have a very distinct memory of tv telling me, "every hour the sun beams enough solar

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B1 US solar energy selenium solar energy renewable sunlight

How We Turn Solar Energy Into Electricity

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    elearn posted on 2015/09/28
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