Solar power: the power of the future
Where do microinverters fit in solar power?
Perhaps the simplest fact we know about solar power is that it comes from the sun. The next fact is that it is classified as renewal energy in contrast to fossil fuels (such as coal, natural gas and oil) which are non-renewable. Renewable energy sources are those that are not finite and will not run out in the future. It is the most used renewable energy at the present and the probability of it being widely utilized in the future is likely. Before that happens, go grab a notebook and list down the basics of solar power.
The two faces of solar power
Solar power can be captured in 2 ways: through solar thermal, or through photovoltaic cells. The former is done through heating where the sun’s rays are used to produce steam. Series of Parabolic mirrors that reflect the sun’s rays are used to heat up water inside steel tubes. Steam produced would then be used to run turbines which would generate the electricity. This method is very ideal during summer in places like California but is economically unfeasible in cloudy areas like Northern Europe.
Another method is through the use of photovoltaic or PV cells. This method may be a lot familiar to us. These are used to directly produce electricity from light energy. This method would be the focus of further discussion below.
Photovoltaics: the basics
As you browse a dictionary, photovoltaic is an adjective that pertains to the generation of voltage when light energy falls on the boundary between two dissimilar materials, as in two different semiconductors.
The photovoltaic process converts free solar energy directly into solar power. Free solar energy is said to be the most abundant energy source on the planet. Mentioned earlier is solar thermal electricity technology which is a “passive” form of generating solar power. The latter is usually used in the heating of spaces and in the production of heated water.
A semi-conductive material is critical in a PV cell. This material is no other than silicon. It is placed as two or more thin layers inside a cell. When silicon is exposed to light, electrical charges are generated and conducted by wires as direct current (DC).
Actually, multiple cells comprise a single solar panel then multiple panels compose a grid system that consequently generates solar power. The output of electricity from a PV cell is very minute that multiple cells must be connected together and encapsulated behind glass to form the module otherwise known as a solar panel. The solar panel is actually the building block of the PV system where a number of panels can be connected together to create the desired electrical output.
The solar panel, technically speaking
As mentioned earlier, solar energy cannot be converted into solar power without the sufficient number of PV cells that are the building blocks of the PV system. Consequently, PV cells-> solar panels-> PV system or the PV array. The PV array, to further emphasize, is composed of individual PV modules combined to produce the desired current and voltage output. The usual domestic PV system that yields 1.5 to 2 Kilowatts peak (kWp) may cover an area of 12-40 square meters (sq m). But this would also depend on the level of technology and on the orientation of the array with respect to the sun.
As also mentioned earlier, electricity carried away by the wires as solar power is in direct current (DC). Appliances anywhere in the world run from alternating current (AC). The usual delivery of direct current by PV modules is 12 volts (V), while most household appliances run at 230 volts (it varies depending on which continent or country you are in). That’s where the dilemma sets in. How did technology overcome this (actually very simple) problem?
Here the power inverter comes into the scene. Solar power inverters are very critical components of the solar energy system. You can actually choose from the conventional string inverter or microinverters. This would be further discussed later.
Aside from these other components of a typical grid-connected PV system are the array mounting structure, cables and switches. These would ensure that the PV system is separate from the main building and from the main electrical source. A meter is also vital to ensure that the solar power supply from the PV generator is credited to the owner.
Solar power inverter, a bird’s eye view
As you have read, inverters or the solar power inverter are used to convert direct current (DC) to alternating current (AC). There is a specific kind of inverters that do the same however in a different kind of way called microinverters. You may ask, how do they work?
The conventional string inverters work in such a way where it is connected to a series or string of solar power panels. These panels would work like a single panel and would be affected by shading of a single PV module. For example, if one panel has a minor manufacturing defect that decreases its output by 5%, the entire series of panels as a whole will perform 5% less. Consequently this would translate to less solar power.
Conversely, microinverters in accordance to its name are small inverters. They are fashioned to suit the output of a single PV module. It can isolate and tune the solar power generated by a single panel. So in a single panel array of a 10-solar module series, the decreased output of a single PV module cannot affect the entire series because each has its own microinverters.
Microinverters are directly attached behind each panel. Solar power arrays are connected parallel to each other and then fed to the grid. Compared to a series, its major advantage is that it a single defective panel or inverter cannot bring down the entire system. More so, when a single panel is at fault it can be directly identified in contrast to a solar panel series.
Any major advantage always has a major disadvantage that comes with it. As there is none that come with its function, the cost being very expensive is its drawback. Not only the cost of its installation and parts are expensive, but most especially the cost of the electricity generated. Because of these, manufacturers limit the number of microinverters’ models they produce because of economic considerations. Models produced seldom exactly match the output from a solar panel, most of them over or under-matched.
There is always a silver lining on the clouds of doubt. Now that prices are decreasing plus that there are existing dual microinverters, the environmentally conscious consumer may still find his/her way to getting their home solar powered. These dual microinverters function the same, except that they are connected to two solar power modules. They accept direct current (DC) input from two which then translates to reduced cost of equipment for prospect solar power suppliers.
Microinverters have changed the name of the game in electricity, and shifted supply from big corporate electrical suppliers down to the grassroots. Microinverters are very ideal in the residential setting where homes have only a small number or solar power modules, more likely less than your five fingers can handle.
Now solar power is not just the power of the future, now that power is yours for the taking.
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