Why Solar Panels Are Grossly Inefficient (But Sometimes the Only Choice)|
Article - March 27, 2016 By LarsonElectronics.com
Why Solar Panels Are Grossly Inefficient (But Sometimes the Only Choice)
Solar energy is an unlimited power source that, in some ways, is very inefficient. At the moment, developments in photovoltaic (PV) technology cannot meet the expectations of mainstream consumers and commercial establishments. However, this does not mean that solar generators are useless. They play a very crucial role in delivering power to far-flung locations, temporary camps and remote bases.
Read on to find out why solar panels are inefficient and the importance of solar generators in supplying power to remote locations.
Second Law of Thermodynamics
The main culprit responsible for the inefficiency of solar cells lies in the second law of thermodynamics. Carnot’s theorem, which was developed by Nicolas Léonard Sadi Carnot in 1824, suggests that this law is the reason why it impossible to create a fully efficient solar cell. In application, for systems that rely on sunlight concentration, the maximum level of efficiency of such units is 85 percent. This figure decreases greatly, as low as 55 percent, when the panels do not track the sun’s UV rays. Interestingly, when outdoor conditions are unfavorable, solar systems have a difficult time tracking sunlight.
But this is only one of many variables that contribute to the drawbacks of solar energy; and it does not reflect the highest efficiency levels of mainstream solar PVs on the market today, which is significantly lower than 55 percent.
Furthermore, it is not possible to capture 100 percent of the sun’s light with PV cells. This is because the sun’s rays are not made up of 100 percent light (it also comes with heat). A study conducted by William Shockley and Hans Queisser, semiconductor physicists, revealed that under favorable conditions, roughly 1,000 watts of natural sunlight reaches earth per square meter. Out of this amount of sunlight, around 33.7 percent can only be used by solar PVs.
It is important to consider that extremely efficient solar energy systems that utilize an array of semiconductor technologies are too expensive for mainstream consumers at this time. An example of such units include concentrated PVs (CPVs), which can reach 86 percent efficiency through the use of thick, reflective mirrors. The rapid advancement of the sector indicates that pricing barriers may fall eventually, as the technology becomes more usable.
Additionally, most of the groundbreaking results recorded from solar energy systems were conducted in controlled environments, such as a lab. In order to get a realistic view of the performance of solar cells and modules, tests should be facilitated in their target environment, i.e., residential rooftops, open fields and commercial spaces.
Alternatives Are Not Any Better
Despite being inefficient, solar energy is sometimes the only choice for individuals or groups living in remote locations. Setting up access to the grid in such locations is a huge undertaking, which entails trenching for electricity poles, lengthy wiring and countless hours of labor. Relying on a fuel-powered generator is the closest option to remote power, but such systems require around-the-clock fuel trips. If the camp is in the middle of a disaster zone or extremely inaccessible due to bad weather, acquiring a constant supply of fuel can be difficult and dangerous.
In such cases, solar power is a very viable option. Deploying a solar generator after arriving at the target location takes less than an hour, depending on the number of devices being hooked up to the system. Compared to fuel-powered variants, solar generators operate quietly without emitting harmful smoke and can be setup close to high traffic areas. Maintenance for such machines are minimal, because they have less moving parts that are prone to wear and tear.
In another study, that was published in the U.S. National Library of Medicine, researchers tested the effectiveness of UV air treatment in commercial office spaces. The group focused on fungal build-up in air-handling units (AHUs) over a span of four months. If not properly maintained, fungus can easily thrive in HVAC systems (filters, insulation and cooling coils). Such contaminations have been linked to a number of respiratory medical conditions, including allergic rhinitis, asthma, and hypersensitivity pneumonitis.
With a reliable battery, users may use stored power when sunlight is not available (cloudy weather and after sunset). This would allow individuals in the area to continue working throughout the night with confidence. Lastly, it is important to consider that solar energy is free to use and does not contribute to harmful emissions and noise pollution. Hence, there is a lot of potential that comes with the nascent technology; and many believe that scientists will be able provide solutions for its inefficiencies in the near future.