Introduction
According to National Geographic, "Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year." (read more here) This abundant power source, which shows no signs of disappearing, is now being harnessed to provide for the energy needs of people on Earth with the latest solar technology.
Solar Installations
Solar installations, which convert the energy of the sun into usable electricity, are composed of three essential parts:
- Solar Array - a cluster of solar modules that gather energy from the sun in the form of direct current (DC)
- Inverter - a device that converts gathered DC electricity from a solar array into alternating current (AC)
- Load - anything connected to a power source that uses electric power
Now for a little bit about each of these parts.
Solar Array
Solar modules consist of cells made of silicon semiconductor material, which allow the conversion of light energy into usable electricity. Little particles of light called photons come beaming towards Earth from the sun and hit electrons resting in the semiconductors of solar arrays. The impact of the photons makes electrons move, and this movement of electrons is called electric current. This current eventually powers lights when we turn on a light switch, but first, it must be converted by an inverter. A group of solar modules is connected in series and parallel to form an array.
Modules vs Panels
Although the two may seem interchangeable, they are very different in design and function.
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Modules Create Electricty (Solar Photovoltaics PV) |
Panels Heat Water (Solar Thermal) |
It is a contentious argument since even the module manufacturers use the term "panel" when describing their products to the public. The public knows them as panels because the solar installers of long ago who installed solar thermal blazed the way for rooftop solar. Once solar PV became popular, people kept calling the glass on the roof "panels."
However, words matter and using the proper terminology is important!
Inverter
There are two types of electric current: direct current (DC) and alternating current (AC). The appliances present in homes require alternating current (AC), but solar modules produce what is known as direct current (DC), so it is an inverter's job to translate DC into AC.
As an aside, these two abbreviations are where the band AC/DC got its name.
The translation of DC into AC occurs through a process involving rapid switching of electronic circuitry. This switching produces the wave-like pattern you see above on the right. An inverter functions in concert with solar modules to follow an MPP (maximum power point), and inverters track this point so that modules connected to them produce the maximum power possible. Inverters often support multiple MPPs so that multiple strings, or rows, of modules, can be connected to them. We'll talk more about strings in the next article.
Load
The load of an electrical system refers to the part that uses energy. In the case of a solar installation, this load is usually a house's electrical system. As was mentioned earlier, the appliances used in homes require AC, not the DC provided by solar modules, so once AC current is passed from an inverter to a house's electrical system, that energy is used in the lights, appliances, TVs, phone chargers, and other electrical devices connected to the house.
Conclusion
These are the essentials of solar energy use! Switches, meters, and other smart devices like those produced by Tigo can be connected to the system to improve its functioning. Still, the core of every solar installation remains the same - a solar array creates energy, and an inverter converts that energy for use by a load.
One last note:
Sometimes, a solar array produces more energy than can be used by a house. This energy must go somewhere, so when this happens, an installation has two options:
- Send energy to a battery for storage and later use
- Send energy to the electric grid for someone else to use
In America, when energy is sent to the electric grid for someone else, utility companies pay homeowners for the excess electricity they produce, reducing electric bill costs. This makes solar energy not only a sustainable opportunity but a potentially lucrative one as well.