Solar Energy 101:
Introduction to Solar Energy
Solar is one of the most talked-about alternative energy sources in the world
today.
 | Enough energy comes from the sun in one hour to power
the global population for a year. |
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Sunlight is a totally renewable resource, unlike oil, coal and natural
gas. |
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We know that our sun is actually a very large and hot star emitting lots of
power in its rays. How do we go about harnessing that power effectively, so it
can help generate electricity, which is an important part of modern life?
The sun’s rays transmit both heat and light. The heat is used in thermal
systems to produce hot water and hot air for commercial and residential heating
use, as well as power generation with steam or sterling engines.
The light is used in photovoltaic systems to convert light to electricity
and this is one of the main areas where our solar industry is concentrating its
efforts today.
The solar industry, like many others, has its own unique vocabulary.
For example:
Photo (light) + voltaic (produces voltage) = photovoltaic (PV) system
How
solar modules work
Solar modules consist of layers of materials like a sandwich. A solar cell
is made from a thin wafer of silicon, similar to a computer chip, but
bigger.
The light carries energy into the cell and the cell and the wires connected
to the cell convert the light energy into another kind of energy – electric
current. No electricity is stored in the cell. If you want to understand more
about photons and electrons and how this all works view this quick video tutorial (26
MB video).
Solar cells are interconnected in a matrix to form a module. One solar cell
produces electricity at a voltage of approximately 0.5 volt at room
temperature, so 36 cells connected together in a module produce enough voltage
to charge a 12-volt battery. However, the solar cell heats up while exposed to
the sun, reducing the operating voltage to about 14-15 volts. A 12-volt battery
needs about 14 volts to charge it, so the 36-cell module is the standard used
in charging 12-volt batteries. The cells are connected and placed between a
tough glass front and a back surface within a frame and sealed, as shown in the
illustration.
Helping solar
cells and modules work better
Dow Corning is developing encapsulant technology to protect the cells
in the module. The encapsulant keeps out moisture and contaminants, which could
cause the module to fail, so it is a critical part of the manufacturing
process. Dow Corning® brand products are also used to seal the
frame, adhere the junction box on the back of the panel and potting agents are
used to fill the junction box. The potting agents protect the electrical
components in the junction box.
Solar modules in
use
Once assembled, the panel is ready for installation. Additional equipment is
needed for off-grid systems, including a battery storage system. Off-grid
systems are stand-alone units that do not feed electricity back to a power
company.
An example of an on-grid system is the solar panels installed by
Dow Corning and Hemlock Semiconductor Group at the Dow Diamond baseball
park in Midland, Michigan, USA, where the excess power generated is sold back
to Consumers Energy, the local utility company. The panels generate electricity
year-round.
Dow Corning and Hemlock Semiconductor Group both play significant roles in
the solar energy industry. Dow Corning provides materials and services for
the entire solar industry, from the basic building blocks of silicon feedstock
for ingots and wafers production to solar module frame assembly and sealing
materials. Hemlock Semiconductor is a world leader in the production of
polycrystalline silicon, the cornerstone material used to produce solar cells
that harvest energy from sunlight.
Learn how solar energy works in your home in Solar Energy 102.
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