Translator: ahmed turk Verified: Abd Al-Rahman Al-Azhurry Earth intercepts a lot of solar energy 137 thousand terawatts Ten times what the inhabitants of the Earth use So, is it likely that one day The world will depend entirely on solar energy? To answer that question First we need to study how the solar panels do By converting solar energy into electrical energy. Solar panels are made of smaller modules called solar cells. The most common solar cell is made of silicon It is semiconductor and is the second most abundant on Earth. In the solar cell, Crystalline silicon is filled between conductive layers.
Each silicon atom is connected to neighboring atoms by 4 strong bonds This keeps the electrons in place and prevents the current from flowing. Here lies the key: A silicon solar cell uses two different layers of silicon N-type which contains extra electrons The p-type contains additional electron spaces called cavities. And at the point where the two types of silicon meet, Electrons can travel through the meeting point (p \ n) Leaving a positive charge on one side And a negative charge at the other side.
You can think of light as a flux of infinitesimal particles They are called photons After launching from the sun. When one of these photons strikes the silicon cell, it has enough energy You can release an electron from its bond, leaving a hole The negatively charged electron and positively charged hole position They are now free to move freely. But due to the electric field at the meeting point (p \ n) They can only go in one direction. An electron is being pulled in the direction of n While the gap is being pulled in the direction of p. The moving electrons are collected by thin metal fingers at the top of the cell. From there, it goes through an external circuit To do electrical work As a running light bulb And that before returning through the conductive aluminum plate at the back. Each silicon cell puts half an electric voltage However, it is possible to arrange them in modules to obtain more power.
12 photocells are enough to charge a cell phone While it takes several units to run an entire house. Electrons are the only moving parts of a solar cell And all of it goes back to where it came from. Nothing gets used up or consumed So solar cells can last for decades. So, what is preventing us from becoming totally dependent on solar energy? There are political factors at work Not to mention the commercial interests that press for the continuation of the status quo. But let's focus now on the physical and market challenges The most obvious of these challenges Is that solar energy is not evenly distributed across the planet. Some areas are sunnier than others. In addition to being volatile.
Only a little solar power is available on cloudy days or at night. Therefore, total dependence will require effective methods For getting electricity from sunny to cloudy areas, And efficient energy storage. The efficiency of the cell itself is also a challenge. If sunlight is reflected rather than absorbed Or if the expelled electrons fall into a gap before they cross the circuit The energy of this photon is lost. The most efficient solar cell to date Only 46% of the available sunlight is converted into electricity Most of the current commercial systems have an efficiency of 15-20%. Despite these limitations In fact, it would be possible Powering the whole world with current solar cell technology. We will need financing to build the infrastructure And a large space. Estimates put it in tens to hundreds of thousands of square miles. Which looks like a very large area, But the Sahara desert alone has an area of more than 3 million square miles. Meanwhile, the solar cells get better and lower the cost And compete with electricity from traditional networks. And some innovations such as floating solar cell farms It can completely change the scenery.
Putting aside thought experiments, There is a fact that there are over a billion people They do not have an approved source of electrical energy. Especially in developing countries, Which has a sunny atmosphere. Therefore, in those places, Solar energy is much cheaper and safer than the available alternatives. Like kerosene. On the other hand, it's for Finland or for Seattle Solar energy is a little out of reach yet..