Choosing the Best Solar Panels or Photovoltaic Modules
What is a Photovoltaic Module?
There has, in recent years, been a huge movement worldwide, to harness renewable energy for both residential and commercial use. Energy from from sun, wind and water has been used in making mans work easier since man was first created. Let us hope that we are finally realizing that sucking the remains of decomposed prehistoric life from another earth age and burning it may not be such a good idea after all. The sun has warmed the planet since the beginning and contains photons that have provided light as well. These photons can now be harvested and converted into electricity by semi conductor cells of silicon. These cells, when placed in groups behind a glass panel, can produce electricity in amounts high enough to offset a substantial part of the cost of buying power when these modules, or solar panels as they are commonly known, are grouped together in an array on a south facing roof or in a field.
There are two basic types of these systems in use today, commonly referred to as on grid and off grid. The names mean exactly what they say. An on grid system produces electricity as DC (direct current) that is converted into AC (alternating current) and feeds it into the meter to the utility power grid, causing a reverse of power at certain times, and actually making the electric meter run backwards, crediting the user for the amount produced. The ability to flow in either direction is a characteristic of AC power. On grid is the most common solar energy producer used today. The efficiency of this system can be increased by daytime light havesting and geotherm heating and cooling. Off grid is an independent stand alone system that powers one or more buildings or machinery. These generally require large storage cells, or a UPS, (uniterrupted power supply), to keep the flow to the power inverter during non daylight hours of operation. These systems are far less common however the success of the MIT liquid battery could make this more plausible. Today we are all becoming more familiar with the rectangular arrays on the roofs of certain homes and businesses characterizing the on and off grid systems.
There are three basic types of photovoltaic modules common, and in use, today. Mono crystalline, poly crystalline and amorphic. All three are forms of silicone that is grown as ingots and sliced into thin wafers. The cost of this production is high and supply and demand makes the cost of the modules fluctuate. Unlike an electric flouoescent lamp or light bulb that costs a basic retail price, more or less, for its wattage, solar panels are priced at a per watt cost with frequent market fluctuations like any commodity.
Mono crystalline or single crystal silicone is the most expensive to produce and also regarded, by most, as having the greatest efficiency. It virtually never fails unless the wires that carry the current become corroded. That is not an expensive fix. These modules can have an expected lifetime performance of 35 years or more at 80% efficiency.
Poly crystalline or polysilicon is less expensive to produce and is regarded, by most in the industry, as slightly less efficient than Mono. Its many rough edges between crystals cause difficulty in the electrical flow. Poly crystalline panels still, generally, have a life expectancy of 25 years or more at 80% efficiency.
Amorphic panels have a thin film spread over a backing and contain a large number of tiny crystals that deter the flow of electricity and are subject to greater degradation over a period of time. This is a very inexpensive option but not for an extended period,
Regardless of the type of module utilized they all must rely on inverters to transpose the DC current into AC, and a monitoring system to continuously check the operation of the system for output fluctuations that could indicate a problem. The inverters can convert inividual panels as microinverters, or groups as central inverters.
Who Needs It?
If you have an overwhelmingly expensive KW rate for your electric power,or live in a state where the sun shines most of the time like New Mexico, and your state has put a demand on the power providers to produce a certain percentage of their energy from renewable sources and there is a state or power company rebate, solar energy is not something you should ignore. It is, in fact, a fast moving train that you should catch now before it pulls out. We can't all, of course live in New Jersey, Pennsylvania or California, where the incentives from the providers and the state government are high. However, despite the great rebate programs in those three states and others , they are not on the list of States that are considered the best choices in the US for solar enhancement. Why? Just because they offer rebates and incentives, in the form of SREC's. (Solar Renewable Energy Credits) that are tradable like stocks and sold at auction, there are other states that offer more, like daily hours of sunshine, or insolation as it is referred, low cost energy installation aside from a high KW cost and an offset of carbon emissions. A state that depends on burning coal creates a huge carbon emission compared to a state that utilizes hydroelectric power.
So to answer my own question, in the subtitle of this article, I will tell you who needs it. Anyone who is concerned with the depletion of natural resources on this planet, who is concerned about global warming due to emissions from power plants. Anyone who has respect for the next generation, if not only the children that will inherit the planet, but also the species of animals and plants that are vanishing as I write.
It is not about how many years until you get a payback or getting green, which you eventually will receive anyway, it is about how much you will pay back and what kind of an environmental legacy you leave or giving green.
Choosing Solar Panels for your Home or Business.
Since the influx of world interest in the implementation of renewable energy systems, several countries have become deeply committed. Germany has led the way in the world for her utilization of solar power. China has become the worlds leader in the production of PV Modules and now the most desirable country to market renewable energy to, according to a recent report. 95 percent of all panels produced in the US, Canada and Europe have at least 49 percent of their components outsourced to China. Other European countries have grabbed the reigns and held on without Chinese dependency. REC, the Norwegian Company with offices in the USA, being one example. They have chosen Singapore for their newest manufacturing operation and are holding to the specs that gave them their reputation of quality. There are a couple of US manufacturers that are still in the homegrown only game today and will remain. These companies will benefit well from the new demand caused by the "Buy American" movement. There are dozens of other brands from factories around the world of greatly varying quality and pricing, and that is what makes choosing confusing, especially for the consumer. Add to that mix layer after layer of manufacturers, vendors, distributors and master distributors, reps and subreps, retailers and internet marketers all claiming to have the best product at the lowest cost. Some who have just entered the market and will exit just as quickly. Some that require purchasing a minimum of hundreds or even thousand of units. Multiply that times several hundred dollars each and that is an enormous investment. Others will sell a freight container to anyone at the lowest price FOB China. If one needs only to buy a dozen, or two, for his residential or commercial roof where does he go? The home center, the installer, an electrical supply house or the internet? The correct answer is the internet but not to buy right away but to study diligently. There are several very informative websites that will rate the various products. Forums from professional groups like LinkedIn and blogs are also good places to get information to help in the decision making process. Check the PTC rating of any product on this California Solar Site. This will measure the true wattage against the manufacturers published wattage. Look for a rating close in number when choosing a product. For example if you are interested in a 240 watt module the PTC rating should be very near that number. The efficiency rating is important also, determined by the square footage output. The efficiency is not all that you should take into consideration. The two most important factors are the annual KWh and the cost. Do not rule out a product just because of its country of origin either. Some products made offshore are of very good quality like Alex Solar which are made in China but are inexpensive and highly PTC rated. As mentioned earlier, many US and European made products have mostly Chinese components and some do not. It is up to you, the buyer, to become educated before making a decision. Ask about support in the future. Will the company still be there to honor that 30 year warranty in 25 years? What about that warranty? Who is offering it? You would not buy an appliance without a sound warranty. PV modules are no different. It is a big investment that you will, hopefully, only make once. One last very important issue, always ask in advance for a factory spec sheet on the product that contains all of the manufacturers specifications and ratings. If it can't be provided move on to another source and do not look back!
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