How do solar panels work? – Richard Komp

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.

About the Author: Michael Flood


  1. 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 !!!

  2. 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.

  3. 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.


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

  6. 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

  7. @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?

  8. 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.

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

  10. 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.

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

  12. 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

  13. "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!

  14. 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.

  15. 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…


  17. 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 🥰

  18. For Florida Commercial or Residential professional solar PV installation, water or pool heater installs, we are the best! check us out at

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

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  21. these are my inventions and wind turbines have a look and subscribe

  22. Use Nuclear Power(Modern Generators, not Soviet Nuclear Tech) as a Temporary solution while we research Fusion Reactors for cities, for the countryside, use Renewable Energy

  23. Using clean and sustainable energy resources are the only way we can preserve the planet Earth.

    Our aim is to utilize natural resources and build a greener, and healthier future! Know more about us at

  24. In South Africa, the ANC govt expects people to register their solar panels and declare their power usage so that they can charge them for using the natural Sun!. Nothings for nothing when you have greedy politicians who want to bleed the populace dry for their own financial gain.

  25. Good video. Informative. It would be even better if the narrator was speaking with such intense vocal fry, frog voice. Annoying.

  26. Yeah, it sounds good right? What is stopping the world to be completely dependable on solar energy? Well, when u tell me where you are going to install all these solar panels around the world, the. We talk. Until then, Nuclear power/fossil fuel babe.

  27. If this can be done in Wisconsin it can be done anywhere. And it is done everywhere here. Sounds like a solar set-up per household is much more efficient than a power company solar set up.

  28. How to get infinite energy
    Step 1: put a solar panel under a light pole
    Step 2: connect the panel to the pole
    Step 3: turn on the pole
    Step 4 enjoy!

  29. there is push for solar in Australia and since Australia started with renewables our electricity cost have risen to become the third highest in the world due to have to have two electricity systems and as more solar panels are installed electricity suppliers are having problems with voltage consistency, also we are hearing hundreds of reports unreliability with the panels themselves lasting years and some even months.

  30. So in theory, couldn't we mount a bunch of magnifying glasses to a board and aim then at a few pipes of water so they get hot enough to make steam?

  31. I think that I have an idea how to store solar energy:
    We just make a generator that gets powered by a turbine that is powered by the solar panels

    So when the solar panel gets sunlight, it will power a generator that will hopefully produce somewhere around 100%+ of the panels power and making the power easier to store

  32. Great video… very interesting, it sounds like humans need to come together and continue working on increasing the designs and structures of the the solar cells in ways to allow us to harness the suns energy more effectively.. like we’ve got all the right ideas now we just need to dig in a little more on our structure design?

  33. E=m[c]^2 This is the law of relativity of Einstein, According to this law, one gram of radioactive material radiates an energy equal to the amount of speed of light squared ( which is 3×10^8) in the mass of radioactive matter. This law applies to the sun, for that reason sun has not extinguished billions of years since the Earth was formed and even before it was formed. Can you imagine that energy!!!, I never forgot when I asked my teacher, "When will the sun's energy end?"He told me to take tea cups and throw them in the Indian Ocean , when the cups fill the ocean then the energy of the sun ends, I was impressed by this answer and began to care about our dear sun .

  34. Great video! I have been looking at the best options for solar panels for a small back yard and this video definitely helped me decide. Another video that is helpful for anyone interested in purchasing solar panels is @t

  35. Me in 1970… happy about our future solar world. Me in 2019… investigates powering a simple space heater, and realizing a $10000 investment with banks of wasteful batteries that only last about 5 years are needed. So ya, blame big oil or governments but the reality is scientists and industry can cause innovation on their own. Quit feeding the myth that we could be green if only some people would let it happen. It'll happen naturally if it does.

  36. Shrugged off the space issue rather quickly. While powering a home with panels on the roof uses space that is freely available, places like deserts are eco systems which can be recovered and made green to produce needed food for consumption and trees for carbon absorption.

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