How To 

How Solar Panels Work


Our ability to generate power has led to some pretty incredible advancements in society. Of course, as with anything else, there are downsides as well. The way we generate most of our power has hurt the environment and isn’t sustainable. One of the more prevalent alternatives that’s not difficult to apply to your own life is the use of solar panels. To find out why they’re a viable alternative, let’s look at how they work:


1. Here comes the sun.
The first thing to note here is that solar panels do not need direct sunlight in order to generate electricity. They won’t work at maximum capacity during cloudy or rainy days, but they don’t stop working entirely. When the sun is shining brightly, though, solar panels can convert up to 22% of the sunlight received. This number might seem dismal, but think about how much energy the sun gives off daily. In fact, it has been estimated that we could cover a relatively small patch of the Earth (say, the size of Spain) in solar panels and be able to provide energy to the entire world.

2. The photovoltaic effect.
The main action of solar panels is to convert sunlight, and it does this through the photovoltaic effect. Solar panels contain a layer of silicon cells, and when these cells interact with light, electrons start to move around which gets an electric current going. This is DC electricity, which means direct current. It needs to be converted to AC (alternating current) to be used by your home, which is what a solar inverter does.


3. Let there be light!
The converted electricity goes into your home and powers your appliances, even through the night. It does this by storing the energy either in a battery or in the electric grid. There’s a process called net metering where any excess energy you create goes back to the power grid, and this is kept track of by your utility company. You get a credit on your bill for the electricity you send back to the grid, which is just another benefit of solar energy.
Dec 22, 2019
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The modern technologies give us an opportunity to improve our life to make it more comfortable. I even would say more independent. For myself I consider solar energy is a crucial at the moment considering the latest climate change.
And I decided to move forward to create my own design of solar power for my country house.
So, I built my own pole and at the top I placed the solar light which has three modes of light power. The pole itself weighs about 23 kg but the basement the most heavy part of this structure.
The main idea was to create an independent pole where you don't need to fix it to the ground or concrete. You can install this structure to any place of your country house or during the day just move it to any place to get the best charge from the sun.
I have attached some photos of my creation. Maybe it was not great idea to build these things but I must reassure you that it works perfectly. In addition you don't need to switch it on or off. Everything is doing automatically.
My best wishes!!!


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Dec 22, 2019
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Thanks for share this article. I think solar energy it's our future. We can save the planet!

Dear Kathyleen!
Thank you very much for your comments and sorry for my late reply to you.
Well, I must admit I am so inspired by my solar light. I love it even though during the winter season as you might understand there is a shortage of energy!!!
My best wishes!
SaraRayne, you might find the following of interest:

To understand efficiency of a solar panel, you must first understand its source of energy – the Sun.

Sun emits energy in a form of light which is composed of photons. Each photon has different energy and wavelength range (from ultraviolet to infrared). Photons are used by photovoltaic cells in solar panels to convert sunlight into electricity.

The cells are made of a semiconductor material (p-n junction), which facilitates generation of electric current when photons get absorbed. But a bigger part of sunlight that hits the cells isn’t converted into electricity. Why is that?

The problem with solar cell efficiency lies in the physical conversion of sunlight.

In 1961, William Shockley and Hans Queisser defined the fundamental principle of the solar photovoltaic industry. Their physical theory proved that there is a maximum possible efficiency of 33.7 percent which a standard photovoltaic cell (based on a p-n junction) can achieve to generate electricity from a light source [2]. In other words, if the sun’s direct light is received by a surface per area of 1,000 watts per one square meter, then the maximum power output that a solar panel could produce is 337 watts per square meter.

This physical limitation is known as the Shockley-Queisser limit and is caused by the physical process of photon absorption by the semiconductor material that knocks loose electrons from their atoms and then passes them to the conduction band within the solar cell. Some photons that hit a solar cell are reflected away from the cell’s surface. Out of those photons that are absorbed, some have their energy turned into heat in a process of internal recombination instead of producing electric current.

These efficiency losses are inevitable. There is no manufacturing process or technology development that can change this limit — at least not with silicon p-n junction solar cells.

The Shockley-Queisser limitation defines the theoretical level of maximum possible efficiency of a solar cell, but in the daily life, efficiency of solar energy conversion is affected also by other factors (discussed below).

Quick Navigation for Why Are Solar Panels Inefficient:

1. Hail, snow, ice and dust
2. Insulation resistance
3. Temperature
4. Solar panel type
5. Design configuration
Improving solar cell efficiency
1. Reducing the shading effects of wires
2. Gallium arsenide triple-junction structure
3. Cadmium telluride thin film cells
4. The Perovskite wonder material

Standard Test Conditions for verifying solar panel efficiency
To establish the efficiency value, manufacturers submit solar panels to several controlled factors that can exist in real world applications. They do this testing to make sure that the design endures these conditions, while at the same time, they verify estimated efficiency (as it is visible in the electrical characteristics of the datasheet).

It is important to know that many manufacturers establish solar cell efficiency based on Standard Test Conditions (STC).

STC are set on maximum possible solar irradiance (1kW per m2), at temperature of 25 degrees Celsius or 77 degrees Fahrenheit, and an air mass of 1.5 (related to the thickness of the atmosphere) [4].

It is rare to have the same conditions in the real life. Temperature and irradiance particularly can be very different from those values.

Nominal Operating Cell Temperature to simulate real life conditions
That is why some manufacturers add the Nominal Operating Cell Temperature (NOCT) among their technical references.

The NOCT is a parameter closer to real life situations and is defined as the temperature reached by an open circuit cell in a module under the following conditions:

    • Irradiance of cell surface: 800 watts per square meter
    • Wind velocity: 1 m/s
    • Ambient temperature: 20 degrees Celsius or 68 degrees Fahrenheit
    • Temperature on the surface: 45 degrees Celsius or 113 degrees Fahrenheit
    • Mounting System: Open back side (to consider air circulation behind the solar panel for refreshing purposes)
Now that you know how efficiency is specified by manufacturers, we can proceed with the factors that are taken into account for the design of solar panels to maintain acceptable efficiency values.

What factors affect solar panel efficiency in daily life?

#1 Hail, snow, ice and dust

Hail could in extreme scenarios damage the surface of solar panels and reduce their efficiency by decreasing the amount of sunlight they absorb. However, you should also know that solar panels are durable and meant to withstand hail at a speed of 20 to 30 meter per second (45 to 67 miles per hour). For a better idea, it is estimated that a hailstone with diameter of 1 centimeter or around 0.4 inches falls at a rate of 9 m/s (20 mph). Solar panels should resist even two to three times that. You should be safe during that early spring overcast.

Thick layers of snow can directly block sunlight accessing solar panels and cut efficiency down to zero [6]. It is important to know that most solar panels can still work with a layer of three to four centimeters of snow (approx. 1.5 inches). If the layer is thicker than that, you should remove the snow.

Just like snow, dust and dirt can influence efficiency values on the same principle. When the layer is too thick to obstruct the light from reaching the solar panel surface, it will affect negatively how much energy the panel produces.

Ice is another element that affects solar panels’ efficiency between 25 to 100 percent, depending on the thickness of the ice layer. To prevent this problem, a silicon coating is applied to a solar panel surface, but even despite that it’s advisable to keep ice off your panels during the winter season [6].

#2 Insulation resistance

Besides the safety concerns, faulty insulation decreases solar module efficiency because current leakages can occur along the edges of solar panels. Be especially careful in areas with high humidity. Humidity speeds up corrosion of materials. Advanced level of corrosion eventually leads to insulation issues and decreases overall solar panel efficiency faster than expected.

Problems with insulation may occur in poor quality solar panels made of cheaper materials, or when solar cells are too close to the frame.

Insulation resistance is especially important for utility-scale projects as higher voltage systems require better insulation properties, which are linked directly to selected materials.

#3 Temperature of solar panels

Solar cells are sensitive to warmer temperature. Higher temperature outside means that the semiconductor material of solar panels gets hot quickly and slightly changes properties, which is linked to electrical losses and voltage drops.

It is estimated that an increase per one unit of temperature above the standard test temperature of around 25 degrees Celsius or 77 degrees Fahrenheit decreases the panel’s energy output by 0.25 to 0.5 percent (depending on the module type).

If you think about it: temperature increase of around 60 degrees Celsius (140°F) could reduce the power outcome of your solar panel by 17.5 percent. So, the effect of temperature can be significant in countries with hot climate. Long term exposure to hot temperature may also shorten lifetime of the material.

On the other hand, you do not need to worry about colder temperatures, as long as the sun shines and solar panels receive unobstructed sunlight during the day, they will be producing at around their estimated efficiency. The only common problem in winter in regard to solar energy production is that the number of sunny days is much lower when compared to summer, and your system generates less on a monthly basis.

Further reading: How Hot Do Solar Panels Get? Effect of Temperature on PV Panel Efficiency

#4 Selection of the solar panel type

Not all solar panels are the same, neither is their price, which very often depicts not only the quality of materials and durability of the product, but also solar cell efficiency in converting sunlight in electricity. In daily life this usually means that you need less solar panels with higher efficiency rating to produce the same amount of power from their surface than you would need if you selected lower efficiency panels.

The main difference in efficiency values of different panel types lies in the nature of how they have been manufactured and what semiconductor material they are made of. The most common semiconductor used in solar cells is silicon. In case of silicon, efficiency still differs based on the type of cells. The best quality are solar cells made of monocrystalline silicon, other common forms are polycrystalline or amorphous cells.

Thin-film solar cell closeup

Monocrystalline panels composed of a single crystal due to their structure allow for the best efficiency between 15 to 22 percent. Polycrystalline panels reach between 13 to 16 percent of efficiency and thin film panels made from amorphous cells have reached to 20 percent.

What also matters is how much light is reflected from the solar cell surface. The goal is to minimize light reflection and that is why many solar panels have special anti-reflection coating and are dark in color – black in case of monocrystalline and thin film panels and dark blue polycrystalline.

Further reading: What Are the Most Efficient Solar Panels for Residential Use on the Market?

#5 Design configuration of solar panels

Among other factors associated with the operation of solar panels, the selection of the orientation towards the sun and the presence of a solar tracking system has a great importance on overall efficiency of your solar system.

Your solar panels will have the best power output when the solar panel surface is perpendicular to solar rays. However, as the sun moves across the sky, their angle changes as well. What you can do to ensure direct irradiance is to install a tracking system. Its downside are higher installation costs.

Solar panel efficiency also changes over the time. Every year that passes after your solar system installation, the efficiency value drops by about 0.5 percent per year. Nevertheless, solar panel manufacturers have to guarantee that the performance of your solar system will not drop below 80 percent when in warranty, which usually lasts 25 years.

Finally, shading is also an important part of the design of any solar system. If your system is shaded for the sunniest time of the day, solar panel output will be affected severely.

New solar technologies to improve efficiency

Despite low efficiency rates among current solar panels, there are several innovative proposals and technologies that aim to change how efficient can solar panels get in the close future.

#1 Reducing the shading effects of wires

Among available proposals is the reduction of the shading effect on solar cells caused by bus bars.

Bus bars are located vertically and horizontally across a solar panel. They can be easily identified by any person as silver wires forming a grid inside a solar panel. They transport electricity generated by solar cells.

Bus bars on a solar panel

These wires, even as tiny as they are, reflect the incoming light in sections where they pass by. In the end, this translates into less irradiance received by solar panels, and therefore, generation of less power.

The idea is to reduce the thickness of these wires, or in the best case to eliminate their interference with the sunlight by placing them on the back of a panel. This would achieve a uniform smooth colored panel [8].

#2 Innovative gallium arsenide triple-junction structure

Another interesting feature that has been set in motion is the development of the new generation of powerful solar cells from gallium arsenide.

Gallium arsenide cells have a triple-junction structure (different from silicon p-n junction) that can be chemically modified to acquire more light radiation than ordinary cells.

Among remarkable advantages of these cells is:
  • Excellent ultraviolet, radiation and moisture resistance;
  • Great performance in the presence of low light;
  • Flexibility and low weight;
  • Efficiency values over 28.8 percent (!).
#3 Cadmium telluride thin film cells

As new compounds are used for the creation of solar cells, new methodologies are also evolving around the manufacturing process to provide high efficiency solar cells.

The solar energy market is ruled by silicon semiconductors, included even in the design of thin film solar panels, but in the short to medium term, new photovoltaic materials like cadmium telluride are starting to gain their share on the market, as promising materials for the development of thin film panels.

The obstacle for their large-scale market introduction arises during the manufacturing process.

Some components seem to be very unstable because cadmium chloride has to be used during the manufacture. However, a new manufacture approach could deliver positive results, if cadmium chloride gets replaced with magnesium chloride [9].

Unlike cadmium chloride, magnesium chloride is abundant and low cost resource that can be obtained from the seawater. This material can also boost efficiency of the thin film panels up to 15 percent.

Perovskite - the wonder material

The ultimate and most promising technology for improvement of efficiency is the perovskite component.

Perovskite, a compound of calcium, titanium and oxygen, offers the possibility to achieve efficiency levels above the current maximum of 22 percent at lower manufacturing costs.

The secret lies in the low costs of raw materials and fabrication methods (printing techniques) that do not require high temperatures and such a high precision as the silicon cells do.

How to easily improve efficiency of solar cells

When you would like to improve efficiency of your solar cells, you should consider the effect of factors discussed above. As you can see, there are some factors that cannot be influenced by you, such as weather and outdoor temperature, but some other factors can be controlled or selected to obtain the best possible efficiency.

The key to success is trying to tackle the factors that can be controlled.
For example: regular solar panel maintenance helps eliminate snow, dust, dirt and ice – all of which obstruct sunlight from effectively reaching the panel’s surface, and therefore reduce efficiency of solar cells.

By keeping your panels clean, you can nicely maintain their efficiency.

Other factors such as the type of a solar panel, its orientation, and the minimum shade configuration are crucial parameters that will determine overall efficiency in the long run.

Some important details that need to be considered are:
  • the solar irradiation value in your area;
  • average cloud density;
  • levels of air pollution;
  • the angle of solar panels depending on their location and a selected mounting system.
These parameters are generally selected by a solar designer but that does not mean that you cannot intervene in the process, especially in the selection of the solar panel type.

Solar panel orientation affects efficiency

Further reading: Solar Panels for Home: Will They Pay Off?


There many factors relating to the inefficiency of solar panels and the foregoing article does a terrific job of explaining their shortfalls in electrical current production over time, due the outside elements and their innate current fluctuations due to the factors involved in their manufacture.
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Dec 22, 2019
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Dear Sir or Madam, thank you very much for your reply!
Well, first of all let me analyze presented information and I will be back to you! I need to absorb all saying by you!
The manufacture of solar panels necessary for such a huge increase in solar power production will require an enormous surge in the mining of raw materials. There are myriad problems that exist with the mining of silicon, silver, aluminum, and copper needed to make solar panels. Can governments and companies ensure that workers in the solar supply chain benefit from safe, just, and well-compensated livelihoods—and that the communities most affected are involved as active collaborators, treated with respect and dignity?

(To understand how those raw materials are put together into electricity-producing panels, check out How Are Solar Panels Made.)

According to the US Department of Energy (DOE), about 12% of all silicon metal produced worldwide (also known as “metallurgical-grade silicon” or MGS) is turned into polysilicon for solar panel production. China produces about 70% of the world’s MGS and 77% of the world’s polysilicon. Converting silicon to polysilicon requires very high temperatures, and in China it’s coal that largely fuels these plants. Xinjiang—a region in China of abundant coal and low electricity prices—produces 45% of the world’s polysilicon.

Reports indicate that some Xinjiang polysilicon plants have employed forced labor of Uyghurs, an intensely persecuted Muslim ethnic minority. In June 2021, a US Withhold Release Order prevented imports containing silicon from Hoshine Silicon Industry Co. Ltd and its subsidiaries from entering the US until importing companies could prove they were not made with forced labor. The December 2021 Uyghur Forced Labor Prevention Act expanded the mandate that all US companies importing silicon from Xinjiang confirm supply chains free of forced labor.


A Gleeson Quarries silica mine in Ireland. Photo credit: CDE Global/Flickr.

Ten percent of the world’s silver is used for solar panels just today, and that brings its own share of problems to the supply chain. By 2050, in a 100% renewable energy scenario that assumes current solar technology and current recycling rates, solar power’s demand for silver could be more than 50% of the world's reserves.

Silver mining, based mainly in Mexico, China, Peru, Chile, Australia, Russia, and Poland, can sometimes cause heavy metal contamination and community displacement. In Guatemala, the Indigenous Xinka community collected more than 85,000 signatures calling on Pan American Silver to avoid restarting its dormant operations due to water contamination, failure to justly consult the community, and potential involvement in threats directed at nonviolent protesters. In La Libertad, Peru, a 17-year-old mine stopped operating in 2012 after five emergency declarations of high levels of metal contamination in the Moche River.

While silicon and silver are the materials for which solar represents a substantial slice of the market, it’s critical to ensure sustainable, ethical sourcing of the other materials, even if only a fraction of global usage. For example, solar panels use a small amount of aluminum, which is sourced from bauxite found near the Earth’s surface. Mining it requires lots of land, often encroaching on Indigenous land, as in Australia, where 28% of the world’s bauxite is produced, and smallholder farmland, as in Guinea, where 22% of it is produced. China produces 22% of the world’s bauxite, and processes 56% of global bauxite into aluminum via a very energy-intensive process.

A former bauxite mine in Hungary. Photo credit: Wikimedia Commons.
Copper has similar land use challenges as aluminum. According to United States Geological Survey, 27% of copper production occurs in Chile, 10% in Peru, 8% in China, and 8% in the Democratic Republic of Congo. In a 100% renewable energy by 2050 scenario, copper demand for solar projectsmay almost triple, according to the International Energy Agency (IEA).

The Institute for Human Rights and Business reports that of the top 300 undeveloped copper ore reserves in the world, 47% are located on or in Indigenous lands, 65% are in high water risk areas, and 65% are in or near biodiversity conservation areas.


The world’s largest open-pit copper mine is in Chile. Photo credit: Martyn Unsworth/

There are three parts of a solar panel that need to be manufactured: the silicon wafer, the solar cell, and the photovoltaic module. Very little of this is manufactured domestically, representing big opportunities for new and pioneering US innovation.

The wafer is the thin metal slice that is turned into a solar cell, and 97% of them are produced in China. A decade ago, the US was producing enough silicon wafers to supply 80% of domestic demand. As of February 2022, there was no domestic production of wafers due to far lower prices abroad and Chinese tariffs, but a few US sites have announced plans to come online in the next several years.

Boron and phosphorous are added to wafers during the manufacturing process. The wafers are then wired with silver, which turns them into solar cells capable of transforming captured sunlight into electricity. While the first US crystalline silicon solar cell plants have announced plans to open in the next few years, no cells are produced in the US today; most are made in South Korea, Malaysia, China, and Vietnam.

A solar PV panel or “module” is made by assembling an array of solar cells, ranging from 36 to 144 cells, on top of a strong plastic polymer back sheet with a sheet of tempered glass added on top. More than three-quarters of PV modules are made in China. It currently costs 30-40% more to manufacture a solar panel in the US. There are about 20 US-owned, US-based solar module and shingle manufacturers, with 10 based in California, and others based in New York, Ohio, Texas, Indiana, New Jersey, and Arizona.

As described above, there are many challenges associated with the materials mining and manufacturing processes needed to make solar panels. But effective policy and technology solutions can ensure that we continue to increase solar power supply and move towards responsible, sustainable solar supply chains, but this movement requires succinct legislation which has not been yet formulated.

Here are four strategies (among many others) that governments and industry can employ to reduce the environmental, social, and energy challenges of solar panel production.

  1. Ensure ethical supply chains. When sourcing raw materials, governments and solar companies can commit to ensuring that mining and refining companies obtain the free, prior, and informed consent (FPIC) of the communities in which they operate. Companies can participate in regulation and evaluation standards such as the Silicon Valley Toxics Coalition Solar Scorecard.
  2. Decarbonize manufacturing processes. Fortunately, new innovations are already reducing the electricity required to make polysilicon. For example, a new polysilicon production process called the “fluidized bed reactor” could use 80-90% less energy than the more widely used Siemens process. Additionally, choosing to produce solar panels in places with cleaner energy sources—along with strategic policy to encourage such siting—can go a long way to reduce the carbon intensityof the process. The recent passage of the Inflation Reduction Act with its tax credits for solar panel-producing companies, and the Biden administration’s 2022 invocation of the Defense Production Act to spur on a domestic solar panel manufacturing industry, are two examples of strategic policy that can accelerate the decarbonization of this industry.
  3. Improve panel, material, and process efficiency. Improving the energy generation efficiency of solar panels means that customers can generate more electricity from fewer panels—which would be easier on the wallet and would require less raw materials in the solar supply chain. While solar panels can last for decades, research and innovation into further extending the lifetime of solar panels can also help customers avoid needing to replace them. Designing panels and solar business models to support easy, affordable, and accessible refurbishment can also extend panel lifetimes. Plus, technological innovation can reduce the amount of raw materials needed in solar panels. For example, engineers have lowered the amount of silver needed in each solar cell by 67% from 2007 to 2016, and it is expected to drop further.
  4. Increase recycling and reuse. Here lies the biggest “silver” lining in the solar panel life cycle story. The two big challenges—raw material sourcing issues and the accumulation of solar panel waste—can help solve one another. Higher numbers of retired solar panels means more recyclable raw materials will be available to supplement increasingly scarce, costly, and international supply chains. Because solar panel reuse and recycling research is still nascent, there are many opportunities for new initiatives and companies to make a big impact. Policy and investment in a new era of circular renewable energy technologies will ensure that the transition to clean power worldwide is as responsible, sustainable, and circular as possible.
And what happens at a solar panel’s end-of-life? Today, we’re installing 50-60 million panels per year, which will generate a million metric tons of solar panel waste when the panels are eventually retired. By 2030, experts estimate we could be installing over 250 million panels per year. This is huge news for accelerating the clean energy transition. It also raises the stakes for ensuring sustainable materials sourcing and end-of-life management. Where will the panels go 20-30 years later when they reach the end of their lifespan? Are there opportunities to achieve a circular solar panel supply chain?

The US solar industry was valued at $33 billion in 2021, employed more than 230,000 people, and continued to grow in power capacity at an average rate of 33 percent per year.

Solar panels generated almost 4 percent of electricity in the US in 2021, up from less than 1 percent in 2015. In some places that number is much higher; for example, 17% of California’s electricity generation came from solar in 2021. Almost half of all new energy capacity added to the US grid in 2021 came from solar. Even more encouraging, by 2030, the solar industry aims to generate nearly a third of US electricity.

With so many solar panels planned for the coming years, you might be wondering: what exactly are solar panels and how are they made?

There are two types of solar technology for electricity generation. The most common are photovoltaic (PV) panels or modules, which use the sun’s light to make electricity. Another technology, concentrating solar power (CSP), uses the sun’s heat instead.

The most common type of PV panel is made using crystalline-silicon (c-SI). That technology accounts for 84% of US solar panels, according to the US Department of Energy. Other types include cadmium telluride, copper indium gallium (di)selenide panels, and thin-film amorphous silicon. Because c-SI panels compose most of the US and global market, I focus on them in this blog.


By weight, the typical crystalline silicon solar panel is made of about 76% glass, 10% plastic polymer, 8% aluminum, 5% silicon, 1% copper, and less than 0.1% silver and other metals, according to the Institute for Sustainable Futures. Graphic: UCS.

Building a crystalline silicon solar panel is a bit like building a sand castle, because silicon comes from sand! Beach sand is silicon dioxide, aka silica. (If beach patrol put that on a warning sign, I bet no one would step foot on the beach!). Silicon, in the form of silicon dioxide sand and gravel, is the second most abundant element on Earth, next to oxygen.

Before it’s used in a solar panel, silicon dioxide must be turned into pure “metallurgical grade silicon” (MGS). This process uses a lot of energy: producing 1 kilogram of metallurgical grade silicon requires 14-16 kWh of power, which is roughly equivalent to using your home oven for seven hours. Still, over their lifetimes, solar panels emit 25 times less carbon dioxide equivalent per kilowatt hour than coal-powered electricity.

Chemistry break! The recipe for cooking up metallurgical grade silicon is
Add 1 part silicon dioxide (gravel) and 2 parts carbon (sourced from coal, charcoal, or wood chips) to an electric arc furnace
Crank up the heat to 2200 degrees Celsius (this is a third of the temperature of the sun!!)
Ta-da! You’re left with 99% pure silicon and carbon monoxide (that’s from the carbon we added, bonded to the oxygen we removed from the silicon dioxide)
But solar panels are perfectionists; they demand silicon to be close to 100% purity. To achieve that, we need to upgrade the silicon into an even more pure polysilicon metal using a process that involves dangerous and poisonous hydrochloric acid and hydrogen gas. (Fun fact: about 12% of the world’s silicon production is currently processed into polysilicon for solar panels.)

Source: UCS

After adding the acid and gas, we are left with chunks of polysilicon metal, which are typically melted down again in a roughly 5-meter-long cylindrical mold. Boron is added to give the metal a positive electric charge on one side. The hot, melty silicon cools and forms a single crystal (“monocrystalline”) structure as a cylindrical ingot. Ingots are any material cast into a rectangular shape, like bars of gold.

(Another process is used to make “polycrystalline” silicon wafers, in which multiple crystals form. This process tends to lead to less efficient panels but can reduce the cost of wafers.)

Next, a wire saw cuts the pure metal blocks of polysilicon into paper-thin, typically 7-inch by 7-inch flat slices called wafers.

Source: UCS

The wafers are heated in an oven and a thin layer of phosphorous is added, giving one side (the opposite of the positive boron side) a negative charge. Next, an anti-reflective coating is added to the wafers because without it these shiny disks reflect sunlight—and we want them to absorb it instead. At this stage, the wafers are now capable of absorbing the sun’s energy and converting it into electrons. Now we need to add silver metal conductors so those electrons can get turned into an electrical current that devices can use!

Silver—the most conductive element in the world—intercepts the electrons in the silicon wafers and turns them into current. The silicon wafers now form a conductive solar cell. Each solar panel, usually containing 60 or 72 cells, uses about 20 grams of silver—a fraction of the panel’s weight but about 10% of its total cost.

Copper metal conductors and wiring connect the solar cells together into one big solar panel, giving it the classic matrix appearance. Copper is a good electrical conductor and very malleable, making it a great material for forming the wiring that moves the current through the panel.

Multiply the above by about 60 million for the US alone, each year.

And then speed it up because we need solar to play an ever-growing role in achieving our clean energy and climate goals.


See: See:

Will clean energy be achieved without the destroying our planet in the process? This appears the issue we are hurtling toward. And no individual, corporation or country should be exempt from honest manufacture and recycling. Crony capitalism must be avoided at all costs.
are you related to einstein?
The first book I received from my mother was "The Universe and Dr. Einstein," by Lincoln Barnett, copyright 1952. I was blessed to have parents who valued books and reading highly. Christmas, for me, was receiving those books I had wished for. My relaxation after school was reading until dinner time - then often reading until I fell asleep in a book.
In high school, I was lucky to have drawn a superb physics teacher, Mr George Youngstrom, from those available - he encouraged me no end.
I read the enclopedia, A-Z, one volume after another.

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