Introduction to Solar Panels and Solar Energy
How are solar panels made? How does a solar system work? Here's a primer on solar energy from one of the world's largest solar panel manufacturers.
How Solar Works
Make Your Roof a Power Plant
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You own the sun. Well, not exactly, but you do have the right to its power. Why not put it to good use? With solar technology, you can turn your rooftop into a power plant.
Most houses use AC power, but solar panels generate DC power. Enter the inverter: problem solved.
This allows the electricity to travel from the solar panels to the inverter and then into your house safely.
These elegant devices sit on your rooftop and turn sunlight directly into electricity without noise or emissions. How cool is that?
Want to go totally off-the-grid? With batteries you can store your own electricity, consume it when you want to, and say goodbye to electric bills! (Not required for grid-connected installations.)
Plugging your solar system into the power meter means flexibility. In some states, when you have extra solar energy, you may be able to share with your neighbors and earn a credit from your local utility.
How Solar Panels are Made
How Solar Panels Are Made
From Sand to Sun
Learn how a humble speck of sand attains the power to turn sunlight into electricity.
Sand: Humble Beginnings
Most solar panels produced today are made from Silicon, the second most abundant element on Earth and the primary ingredient in beach sand. The first step in making a solar panel is to create silicon ingots, giant blocks of high-purity (99.999999%) silicon.
To do this, we put hundreds of pounds of silicon chunks (i.e. rocks) into a giant crucible and add a little boron (called a ‘dopant’) to give the silicon positive polarity. Then, we cook it altogether at over 2,000 degrees Fahrenheit!
Ingots & Wafers
Next, we let the large silicon ingot cool down before slicing it into thin wafers using wire saws. Each fresh-cut silicon wafer is less than 200 microns thick – similar to a heavy piece of paper. These wafers must be carefully handled, inspected and cleaned before further processing.
Once ready, we reduce the reflectivity of the wafer from about 30% to 10% through a chemical surface texturing process that creates tiny pyramids on the wafer’s surface. Now, when a photon hits the wafer's surface, it is more likely to be reflected into the wafer rather than back into space.
Solar Cells: From "Photo" to "Voltaic"
- N-TYPE SILICON
- FRONT ELECTRODE
- BACK ELECTRODE
- P-TYPE SILICON
It's time to turn our silicon wafer into something that converts sunlight into electricity. This is where the solar cell, the heart of a solar panel, is officially born. To do this, we first inject phosphorus into the silicon wafer at high temperatures. Then, we carefully clean the phosphorous off the rear surface and around the edges of the wafer.
Now we have a photovoltaic (photo = light, voltaic = energy; thus, “light into energy”) device! Next, we deposit metal contacts on the front and rear surfaces of the cell, allowing us to collect those electrons generated in the silicon. We also deposit a thin chemical layer on the cell's surface to reduce its reflectivity from about 10% to 1%.
Solar Panel Assembly
To make a solar panel, we string together 48, 60, or 72 of our solar cells and lay them carefully within an encapsulant, which attaches high-transparency glass on the front surface and a highly durable, polymer-based backsheet on the backside. Then, we warm the whole stack (like a toasted solar sandwich) to create a protective cocoon around the solar cells.
Next, for structural stability and long-term protection, we place rigid aluminum frames around the perimeter, bonded together with a waterproof adhesive. Finally, we add a junction box to the back of the solar panel: a connector to facilitate the flow of electricity. Now, the solar panel is ready for quality testing, packaging, and delivery.
Sun: Unlimited Energy
Once your solar panel is installed on your rooftop, sit back, relax, and let the sun save you money. Write a book, make coffee, or watch a soccer match on TV: you choose what to do with your solar electricity.
Furthermore, solar panels don’t have any emissions and they don’t make noise: they just sit there and do their job. Finally, take pride in the contributions you have made to combat climate change and to ensure a sustainable future for all.
History in the Making
The Global Solar Movement is Here
Solar energy is everywhere. You may not be able to dig a coal mine or oil well in your back yard, but with Yingli Solar panels you can harness nature’s highest source of power.
The sun sends enough energy to Earth each hour to meet human energy demands for an entire year! It’s the world’s most abundant and accessible source of energy.
Perez, Richard, ASRC, University of Albany. As seen in: SHC 2008 Annual Report. International Energy Agency. March 2009. [%a%Source%/a%]
Energy Resources of the World
TERRA-WATTS PER YEAR*
- Natural Gas
Any serious, long-term global energy source must be scalable. Fossil fuels are generally supply constrained: as demand goes up, so do prices. With solar panels, it’s the exact opposite: as demand goes up, prices tend to go down!
The solar industry’s learning curve has been unprecedented. For the last 30 years, each doubling in global solar panel production has correlated with a roughly 25% reduction in solar panel prices!
Bloomberg New Energy Finance. As seen in: Solar Silicon Price Drops Brings Renewable Power Closer. Bloomberg News. March 2012. [Source]
Conversion Efficiency Of Silicon Wafer
How do we want to leave the Earth for our children?
Silicon solar panels generate electricity without noise or emissions, and are comprised almost entirely of recyclable materials (like silicon, silver, and aluminum). In addition, solar (photovoltaic) panels do not require water for operation. This is critically important for sustainable communities around the world.
Learn more about Yingli's commitment to sustainability in our own solar panel production processes.
Farrell, John. Water Use May Decided Future of Centralized Solar Power. Institute for Local Self-Reliance. May 2011. [Source]
Water Use for Power Plants
Gallons PER MWh
- Gas CC
- SOLAR PVs
A Timeline of
The History of Solar
Legend holds that Archimedes, a Greek scientist, used a series of mirrors on the shoreline to concentrate the sun’s energy and set fire to incoming enemy ships.More...
A.E. Becquerel observed that shining light on certain materials would cause the creation of electric current. This was the launching point for photovoltaic technology.More...
1st Solar Cell
Charles Fritts produces the world’s first solar cell, a device that converts sunlight into electricity, using selenium and gold. The cell’s efficiency was less than 1%, meaning than less than 1% of the light energy was converted into electricity.More...
Albert Einstein is awarded the Nobel Prize in Physics for his “discovery of the law of the photoelectric effect.” Einstein was the first to postulate the existence of light quanta, now called photons, providing a theoretical foundation for modern PV technology.More...
Silicon solar cells make their way into the mainstream market. The New York Times noted that the silicon cell could lead to “the harnessing of the almost limitless energy of the sun for the uses of civilization."More...
The space race between the U.S. and Russia sparks significant investments in solar technology. Some of the earliest man-made satellites, including Vanguard 1, were powered by photovoltaic cells.More...
20% Efficient Cells
A silicon solar cell breaks the 20% efficiency barrier. High-efficiency, low-cost silicon solar cells make their way into commercial production.More...
1GW of Solar
Cumulative global solar installation passes 1GW, a critical turning point for our industry’s global development.More...
The Silicon Rush
Solar industry surpasses the computer industry as the largest consumer of high-purity silicon. Although this created a temporary silicon supply shortage, it sparked major industry investments that lowered the price of solar panels.More...
$1/Watt Solar Panels
The cost of high-quality silicon solar panels falls to roughly US$1 per watt, opening new markets around the world and driving a global energy revolution.More...
New Global Leader
Yingli Solar becomes the world's largest solar panel manufacturer, as global demand for solar panels grows to over 30GW per year.More...