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Solar Energy



The Sun was humankind’s first source of power and with a little work may be the last one we will ever need. Do you know? A good desert collects more solar energy in six hours than the entire world uses in a year. The surface area of your body is maybe about a meter and a half squared and if you laid out in the Sun all day long every day for a year, you would collect about 1500 watts of solar energy.

Anyway, pretty much all of the power that we humans use originally was solar power. All coal is the fossilized remains of plants and animals that died aeons ago and has been buried in the earth and they got their energy from the Sun. Natural gas and oil same thing the Sun. The nuclear power which produces about 20% of our power is one of the two sources that we have, which is not originally solar power and the other one is tidal which is created by the Moon. Well if you are thinking Hydroelectric power then-No cause water which runs down the rivers come from Ocean by evaporation with the help of the Sun. Wind power as you may have guessed by now all weather on our planet is created by the Sun. Burning trees and corns husk and other biomass which we do in biomass power plants all of those organisms originally got their power from our Sun. Then we have direct solar power, which gets its energy from the Sun and skips all those middleman, so it must be more efficient, right?

Well, It turns out it is more efficient and you do think that being more efficient it would be less expensive, unfortunately, it is not.  When we think about solar power generally what we think of is photovoltaic cells, those big blue panels that people put on their roof to generate electricity. You might be surprised to know that we have known about this photoelectric effect for almost 200 years. It was discovered in 1839 by a 19-year-old kid named Edmund Becquerel.

Edmund Becquerel is part of what we call a scientific dynasty. So Edmund Becquerel discovered the photoelectric effect. His father discovered how to refine ores into their pure metals using electrolysis and his son, along with Marie and Pierre Curie discovered radioactivity.  It’s just interesting to me that there can be that much scientific talent generation from generation in one family.

Anyway, the most efficient solar cell that we have created had found their way into outer space because efficiency is expensive, but it doesn’t matter how expensive something is when you are dealing with the International Space Station because it is not like you can run wire up to it. The International Space Station has 212 ft. long solar wings. All combined at peak these Solar Panels Produce 120 kilowatts of electricity which is a lot.

So now let’s understand the most important part photovoltaic panels. In simplest, if you hit a wafer of polysilicon with light some of the electrons on that silicon will get knocked off and they will be free electrons. Now, this is something that is normal, but it is not anything like the amount of power that you would need to create a solar panel. But what scientists and engineers figured out is that if you dope,(that’s a technical term it just means lacing it with impurities), the silicon with phosphorus it suddenly has way too many electrons and then you get what we call N-type silicon, N because is is negative. and then if you take another wafer of silicon, and you dope it with boron you will get P- type silicon, P for positive. A traditional solar panel is just a layer of N-type silicon sandwiched on top of a layer of P-type silicon and then connected with a conductor which we call a wire. stick something on top of that wire and you can power it with a solar panel.  Depending on the size of that panel it could be a calculator, a house or a space station.



The trick is how do we either get solar panels to be so efficient that they can make up for their high costs or We can find new less expensive materials that we can use to create photovoltaic panels.

 Now I have to get off topic a little bit here and talk about how solar power has an advantage that not a lot of people think about. In generals when we produce power as humans we do it at grant power station which are often hundreds of miles away from where the power is actually used. In order to get the power from the power station to your house, you have to put it on these giant transmission lines which are extremely expensive and also having the power travel all that distance is inefficient. You can lose as much as 30% of the power that you generate just getting it from one place to another which frankly is embarrassing. We created all those megatons of carbon dioxide just so we can lose the power when we are distributing it. But with solar power, you can actually generate the power exactly where you are using it. You can put the panel on your roof and use it in your house. We call it distributed power and it is great.

It does sometimes make sense to use solar power in a centralized fashion giant fields full of solar panels especially if those giant fields are in places where the sun shines 364 days a year. But don’t get too excited despite the marvellous efficiency of distributed power. Solar panels still remain much more expensive than centralized power stations. Photovoltaic panels now blanket rooftops all over the world but while they make ecological sense they still don’t make economic sense. Getting a good value for your dollar from a solar panel is pretty much impossible, which is why we are still so reliant on coal and natural gas for most of our electricity.

To this day we get more power from burning woods than we do from the solar panels. So you might be saying to yourself that there got to be a better way to do this and maybe there is if you were a particularly malevolent or scientifically- minded child, you may have experimented with a magnifying glass to create power and you are probably used that power to burn paper or to light a match. Sunlight carries a lot of energy and if you concentrate it into one place you can do a lot of work and I prefer if we would be using that work to push electrons into your house so you can watch your pc or smartphone whatever you are holding now. But Magnifying glasses are far too expensive to use in solar power plants so instate we use mirrors. These are called concentrating solar power plants. In general what has been done is that we use the mirror to focus light on a single point and there is two real ways that it is done. One you build a giant tower and then you fill a field with mirrors and you make sure that the mirrors are always focusing the sun on the top of that tower. Now as you might expect building a giant tower that can handle being heated to some ridiculous heat is kind of expensive but it is cheaper than pure photovoltaic. Second they will build giant mirrored  thoughts like parabolic sort of half-cylinders and in the middle of those they will put  pipe so by the time the water finished traveling, it is so hot that As soon as it enters in bar, the water immediately vaporizes and that's generally how powerplant work, you vaporize water and the vapor takes up much more space than the liquid and so these is a tremendous amount of pressure and they use that pressure to drive turbine, which creates electricity. But even with all that fancy engineering concentrated solar power plans still, in the best of circumstances only produce power at about 11 cents per kilowatt-hour, which is about twice as much as the natural gas power plant.

But wait a minute, now we got two solar solutions. One, photovoltaic where the capture of the energy is the most expensive part and two concentrated solar power where the conversation of the energy into electricity is the most expensive part. What if we could have both of these technology and have the best of both worlds? Well, it turns out that we can and it may just be the one solution that allows solar power to become cost-effective in our energy market. By using really sophisticated photovoltaic cells that can take in far more power than the one in your calculator. Engineers and scientists are using mirrors to concentrate light on very small photovoltaic cells. Now, mirrors which are actually capturing the light are 10 times bigger than the solar panel and thus the solar panel is taking in 10 times more sunlight and producing 10 times more energy but the solar panel itself the expensive part, stays the same size. Using this technique which we call “concentrated photovoltaic” we get the most cost-effective form of solar power that we currently have on the market today. They call it CPV for “ concentrated photovoltaics” and there several gigawatts of it getting ready to go online in the next 10 years or so. It’s important to note that a gigawatts is a lot of electricity that's about as much as produced by the largest nuclear power plants in America.

Now Going back to the space station for a moment mostly just because I want to show more of it. As I said before it doesn't matter how expensive the panels on the Space Station are cause there is no other way to get power up there. Now when I sad that those solar panels create about 120 kilowatt of electricity I was kind of lying to you. About half the time the panels on the Space Station are producing 0 watts of power and that's because it is in the shadow of Earth. And here on Earth when we are standing here we call that shadow night time and it is the nemesis of solar power. So unfortunately it would seem that solar power could never satisfy 100% of our energy need. We will always need something else whether it is coal or nuclear or natural gas to keep the lights on at night. Unless of course, we find some way to store the power up during the day and then let it all loose at night. Well, turns out we can do it by saving it in the battery. Any way there is a term in Physics call conservation of energy that means you can't get more out of a system than you put in. What I am trying to say is Solar Energy is expensive but if we love Our home sweet home Earth we should ignore the cost.

If You Have Any Queries Then Feel Free To Ask Us Down In The Comment Section And Visit To The Science Thinkers Again. As Always Stay Curious And Thank You
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