Solar power energy systems are becoming increasingly common fixtures both at home and in the workplace. However, perhaps owing to such characteristics as their default location out of sight on rooftops, working with quiet efficiency and very little need for maintenance or repairs; they are often easily ignored. In fact, when you dig a little bit deeper, you will discover that there is more than meets the eye when it comes to solar panels and the entire world of solar photovoltaics. We provide you a glimpse of this amazing world with these little known facts about how solar energy systems work.
1. Solar Panels Work better in Cold Weather than in Blistering Heat
Although direct overhead sunlight is great for producing electricity using solar panels, blistering hot weather is not good for the efficiency of solar PV cells. Once temperatures rise above 40 degrees Celsius, the efficiency with which solar electricity is produced drops down significantly. However, it is important not to take this observation out of context.
An area with good amount of sunlight will be better for solar panels than an area where the sky is usually overcast. But in the heat of day, solar cells will lose a bigger proportion of electricity due to inefficiencies within the cells than on a colder day.
A recent Yale study actually proved that some of the world's coldest areas hold the best potential for solar PV energy. Such areas include the Himalayas and the southern Andes. The areas are considered prime locations for installing solar panels because the high altitude means they get even more sunlight and the cold weather all day long means they can generate electricity with even more efficiency than in other areas on the earth's surface.
2. Electricity from Solar Panels has to be Converted from DC to AC and Back to DC
Solar Panels by default produce electricity in the form of direct current (DC). This would sound like a good coincidence since most household appliances such as electronics all require DC electricity to run. However, before the electricity from solar panels is connected to your domestic wiring, it needs to be converted to alternating current (AC) format. This conversion is performed by connecting solar panels to DC-AC inverters.
This conversion is necessary because manufacturers of electronic consumer goods design them to be plugged in to AC power connections (the type of electricity provided by utility grid companies). However, electronic appliances at home have inbuilt regulators which convert the AC electricity back to DC format. It is an oddity which ends up making solar energy systems much more expensive and less efficient than they should be. This state of affairs may not last very long as there are some experts who are contending that DC electricity is a better standard for grid transmission.
3. It is not Practical to Use Moonlight or Artificial Light to Power Solar Panels
Solar panels require direct illumination from the sun to produce any electricity. It is however worth noting that the only useful rays for production of electricity are the infra red rays from the sun. These are the ones which contain an adequate enough number of photons (energized light particles) to cause flow of electrons (electricity) in semi conductor materials such as silicon. Therefore, while sunlight is very effective in producing electricity in solar PV cells, the same cannot be said of moonlight and artificial light.
The moon does not produce its own light but rather reflects rays of the sun falling on its surface and beams this back to the earth. Of the light reaching the earth's surface from the moon, a very insignificant proportion comprises UV rays. The number of photons hitting the PV cells at night is unlikely to cause significant electricity to flow. Even on a night with a full moon, the little electricity produced will be lost out due to the inefficiencies within the solar cells and transmission media.
The same argument above can be made for other artificial light sources such as street lights. In particular, sodium lamps which are considered very efficient because they convert just about all the electricity they receive to visible light, cannot stimulate solar cells to produce electricity. However, incandescent lights such as the traditional filament bulb are thermal sources of light, much like the sun itself. Such light will contain a significant amount of photos from the ultra violet spectrum to power a solar panel. However, to make these work, it would be necessary to use mirrors or lenses to concentrate the light to the solar panels and thus defeating the purpose of having the street lights in the first place.