How do solar panels work? – Richard Komp

The Earth intercepts a lot of solar power: 173 thousand terawatts. That’s ten thousand times more power
than the planet’s population uses. So is it possible that one day the world could be completely
reliant on solar energy? To answer that question, we first need to examine how solar panels
convert solar energy to electrical energy. Solar panels are made up of smaller units
called solar cells. The most common solar cells
are made from silicon, a semiconductor that is the second
most abundant element on Earth. In a solar cell, crystalline silicon is sandwiched
between conductive layers. Each silicon atom is connected
to its neighbors by four strong bonds, which keep the electrons in place
so no current can flow. Here’s the key: a silicon solar cell uses
two different layers of silicon. An n-type silicon has extra electrons, and p-type silicon has extra spaces
for electrons, called holes. Where the two types of silicon meet, electrons can wander across
the p/n junction, leaving a positive charge on one side and creating negative charge on the other. You can think of light
as the flow of tiny particles called photons, shooting out from the Sun. When one of these photons strikes
the silicon cell with enough energy, it can knock an electron from its bond,
leaving a hole. The negatively charged electron and
location of the positively charged hole are now free to move around. But because of the electric field
at the p/n junction, they’ll only go one way. The electron is drawn to the n-side, while the hole is drawn to the p-side. The mobile electrons are collected by
thin metal fingers at the top of the cell. From there, they flow through
an external circuit, doing electrical work, like powering a lightbulb, before returning through the conductive
aluminum sheet on the back. Each silicon cell only puts out
half a volt, but you can string them
together in modules to get more power. Twelve photovoltaic cells are enough
to charge a cellphone, while it takes many modules
to power an entire house. Electrons are the only moving parts
in a solar cell, and they all go back where they came from. There’s nothing to get worn out
or used up, so solar cells can last for decades. So what’s stopping us from being
completely reliant on solar power? There are political factors at play, not to mention businesses that lobby
to maintain the status quo. But for now, let’s focus on the physical
and logistical challenges, and the most obvious of those is that solar energy
is unevenly distributed across the planet. Some areas are sunnier than others. It’s also inconsistent. Less solar energy is available
on cloudy days or at night. So a total reliance would require efficient ways to get electricity
from sunny spots to cloudy ones, and effective storage of energy. The efficiency of the cell itself
is a challenge, too. If sunlight is reflected
instead of absorbed, or if dislodged electrons fall back into
a hole before going through the circuit, that photon’s energy is lost. The most efficient solar cell yet still only converts 46% of
the available sunlight to electricity, and most commercial systems are currently
15-20% efficient. In spite of these limitations, it actually would be possible to power the entire world
with today’s solar technology. We’d need the funding
to build the infrastructure and a good deal of space. Estimates range from tens
to hundreds of thousands of square miles, which seems like a lot, but the Sahara Desert alone is over
3 million square miles in area. Meanwhile, solar cells are getting
better, cheaper, and are competing
with electricity from the grid. And innovations, like floating solar farms,
may change the landscape entirely. Thought experiments aside, there’s the fact
that over a billion people don’t have access
to a reliable electric grid, especially in developing countries, many of which are sunny. So in places like that, solar energy is already much cheaper
and safer than available alternatives, like kerosene. For say, Finland or Seattle, though, effective solar energy
may still be a little way off.

100 thoughts on “How do solar panels work? – Richard Komp”

  1. So do the electrons on the N side go do work (e.g. light a bulb) and then get fed back to the P side? Don't the electric companies often take the electricity from a solar-powered house and send it elsewhere? Then how do the holes on the P side get filled again? And if an electron can do work and then return to it's place on the P side only to repeat the process then what get's "used up" in the work that it's doing?

  2. This is AWESOME! We talk about this stuff on our channel.

    Estamos basados en México, y en Invictus estamos buscando cambiar a la mayoría de los hogares e industrias a energía 100% renovable!

    Si te interesa este tema, pasa por nuestro canal!

  3. to more information

  4. Are the two layers N and P separated by a physical barrier? I struggled to understand why the electrons would have to travel through an aluminum conductor, before reaching the positive side, and not just hop right to the hole on the P-side

  5. You should watch a video about what if we covered the desert with solar panels from yt channel What If

  6. you not using solar panels as efficiently as you could be using a montesino motor to turn a generator food condens the amount of solar panels you would need dramatically

  7. This video is actually inaccurate af
    It loses out a key important factor
    Solar panels cause pollution that impacts environment heavily during the process of produce

  8. Look up the antelope valley on Google maps. There are so many solar pannels that it looks like the valley floor is covered in lakes.

  9. I’m sorry how can this be right? If the n side is negatively charged the electron will be pulled to the p side, not the n side

  10. Imagine how far along we would be if governments all shared their information and increased funding towards solar energy research instead of pumping more oil .. but in 20 years we will be much more advanced towards sustainability using solar and batteries

  11. It's funny they can come with all these terms. What happens when the PNA/NAO,ENSO all interact with the PN all overseen by the CIA?

  12. The main problem is not business status quotas that lies in the monopoly/anti trust issues we need to use. That is the only way to defeat the energy monopolies is to use Anti Trust. Communism only ensures one voice and that's the government's not yours. Now only a VERY tiny fraction of oil energy actually goes into car use. 95 percent of our oil goes into every day products and fashion. Our shoes all need oil.

  13. Without oil a lot more then cars would grind to a halt and throw us back to the dark ages with quadriple the population to feed and horse manure piling several stories high and major epidemic disaseses as a result. Hence why NYC was more then happy to go with cars. Eventually NYC got a lot cleaner. Despite smog it's a lot cleaner then horse manuer. Only the Dutch with wooden shoes would be unaffected since nobody drive's in that country they use horses and wooden shoes! 🙂

  14. Thanks to the socialist nanny states making it impossible to get anything done we are now literally when Africa was poor in the 1960s. It's just not officially covered by the press. That is also why we are not innovating anymore. Without investors we cannot invest. China has thrown what little freedom they gained in the 90s and 00s with their social credit system. They are regressing back to the 60s when millions mysteriously 'vanished' if you spoke out against their system. Most of these solar panels are at some point made there. Do you really think the Saudi's have people making all the tools and materials for the panels in factories of their own using their own citizens?

  15. Yea key words to wats holding us back from converting the world to solar: $$… trillion dollar electric companies and the political lobbyists are never gone give up their profits no matter how much it would benefit the mass population nor our planet in general. Poor mother earth… -_-

  16. check for the advantages ..

  17. Real Research :: If we cover the entire Sahara Desert with solar panels . The Sahara Desert will no longer a desert . The plant will start to grow . Rain will be usual thing there .
    So please tell this problem to people must !!!

  18. I hope you don't mind if I am using this video in my solar energy presentation it is full of useful information I will definitely give you credit.

  19. Nice video but there is a mistake at 1:14: The P-Type will become negative, not positive and the N-Type will become positive, not negative.


  21. Anyone considering converting to solar panels and looking for a free home or business consultation please follow the link;

  22. Yeah it's all a money game between solar wind and all the moving water we have we could be 100 percent green I mean the Mississippi river alone could power the US .a motor can run off hydrogen but then what would they sale

  23. @TED-Ed, isnt the + and the – on the wrong sides ( 1:21 ) ? Because when the electrons from the N-side move to the P-side should the leave a positiv load on the N-side because there more protons then electrons now… am i right?

  24. There is no money in clean energy. Always remember that. Those people who will lose the most, will do their best to stop the expansion of solar.

  25. The irony in my country is basically always sunny yet solar panel really expensive and not socialize better like other 4 seasons country.

  26. 15 to 20% efficiency. Everyone ignores this . Multiply that by .5 ( day and night) then multiply that by .5 again for sunny day vs cloudy day. 3.75% to 5% is the answer. That is why you hardly see solar panels anywhere. The green new deal avoids this. Or claims otherwise.

  27. That's actually SO COOL though. I love how TED makes complex concepts easy to understand, and I always love the visuals.

  28. I live in a Town in Turkey and there is a solar farm that is supporting the main grid [ It was built by the Government ] and our electricity bill monthly is around 5-7 dollars, but We have 10 hours of full sunlight hours and no clouds at all so its pretty powerful and the efficiency is 20% according to their website. I think it's a pretty cool power source for places like here especially in the future when they have higher efficiency

  29. "173,000 terawatts. That’s 10,000 times more power than the planet’s population uses" THEN WHY DO WE HAVE FOSSIL FUEL THAT'S KILLING US ALL. LETS HAVE 100% RENEWABLE ENERGY!

  30. The most used solar panels last 8-15yr…. Tindo and Australian company has made them to last over 30years..

    Coal is 40% efficient and look like being even more efficient in the future.

    To build a solar panel that is 22% efficient you end up spending 2.5 x more coal than the solar panel produces in energy over its life time.

  31. How do they work.. well they dont… they are Extremely inefficient. Its only Governments rebates that make it cheap for those who are rich who can spend money to get them on their house… poor renters cant… poor renters pay full price for power and get poorer and poorer…


  33. Putting solar panels in the sahara is a terrible idea due to the sand storms etc which would cause these to require more maintenance than they already need.

    Edit: Solarpowered Stirling engines on the other hand 🥰

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  35. Technically we can’t because of policial reasons. 🤷🏻‍♂️ I honestly didn’t see a problem with the others he listed.

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