You may hear the term “efficiency” thrown around a lot when reading up on solar panels. It sure sounds like a good thing, but what exactly is solar panel efficiency? How is it measured?
We will go over a number of the main factors causative to the efficiency of solar panels, environmental factors that play a role, and some of the most efficient solar panels on the market today.
WHAT IS THE EFFICIENCY OF SOLAR PANELS?
Solar panel efficiency can be defined as a measurement of the panel’s electrical power production over the sun’s energy transferred to the panel. The electric power can be produced when sunlight interacts with the solar cells in the panel causing DC(Direct Current) flow through the wiring and bus bars to be converted into AC (alternating current) energy. The AC energy is then sent to your Main Panel and distributed throughout the house. You can read more about how solar panels are manufactured in this post.
Measuring efficiency is fairly simple. If a solar panel has 20 percent efficiency that means it’s capable of converting 20 percent of the solar light hitting a panel into electricity. The highest efficiency solar panels on the market today can reach almost 23 percent efficiency. The average efficiency of solar panels falls between the 17 to 19 percent efficiency ranges.
FACTORS THAT AFFECT SOLAR PANEL EFFICIENCY
Solar Technology is continuously getting better. Solar panels have been consistently increasing inefficiency at about 0.5% annually since 2010. Numerous scientific factors play into the solar cell efficiency equation. Three major components are:
- Panel material components
- Reflectance efficiency
- Thermodynamic efficiency
Monocrystalline vs. polycrystalline refers to the makeup of the solar cells in each type of panel. Monocrystalline refers to solar cells cut from a single source of silicon whereas if we talk about polycrystalline solar cells, they are typically less efficient due to their more fragmented composition.
If we compare efficiencies of both the type we can see that as Monocrystalline solar cells have uniform composition, they have better efficiency as compared to polycrystalline solar cells. Additionally, Monocrystalline solar panels tend to achieve superior performance in less optimal conditions such as high heat and low light. Nearly all residential panels today are monocrystalline.
Reflectance efficiency is determined by how much sunlight is reflected and how much is absorbed. Less reflection means better efficiency. Glass, one of the most important components of a solar panel, reflects a very small portion of the light that falls on it.
To reduce reflectance there are many ways, such as anti-reflective coatings, which are nearly used by all solar panels on the market today.
Thermodynamic efficiency is the maximum efficiency possible. The sun’s energy could be converted into electricity at the height. This number is right around 86 percent, the thermodynamic efficiency limit.
The way photons interact with solar cells, they can only generate electricity from the sun’s energy up to a certain point. After that point (86 percent) thermal energy, or heat, is created.
To improve the thermodynamic efficiency of solar panels we construct multi-junction or tandem solar cells. This improves efficiency by dividing the solar spectrum into smaller areas, which raises the efficiency limit for each section.
FACTORS AFFECTING CONVERSION EFFICIENCY
Not the entirety of the daylight that arrives at a PV cell is changed over into power. Indeed, its greater part is lost. Various elements in solar cell configuration assume functions in restricting a cell’s capacity to change over the daylight it gets. Planning considering these elements is how higher efficiencies can be accomplished.
WAVELENGTH – Light is made out of photons—or bundles of energy—that have a wide scope of frequencies and energies. The daylight that arrives at the world’s surface has frequencies from bright, through the noticeable reach, to infrared. At the point when light strikes the outside of a solar cell, a few photons are reflected, while others go directly through. A portion of the assimilated photons has their energy transformed into heat. The rest of the perfect measure of energy to isolate electrons from their nuclear bonds to create charge transporters and electric flow.
RECOMBINATION – One path for electric flow to stream in a semiconductor is for a “charge transporter, for example, a contrarily charged electron, to stream over the material. Another such charge transporter is known as an “opening,” which speaks to the non-appearance of an electron inside the material and acts as a positive charge transporter. At the point when an electron experiences an opening, they may recombine and consequently counteract their commitments to the electrical flow. Direct recombination, in which light-created electrons and openings experience one another, recombine, and transmit a photon, inverts the cycle from which power is produced in a solar cell. It is one of the crucial elements that limit productivity. Backhanded recombination is a cycle where the electrons or openings experience pollution, an imperfection in the precious stone structure, or an interface that makes it simpler for them to recombine and deliver their energy as warmth.
TEMPERATURE – Solar cells for the most part work best at low temperatures. Higher temperatures influence the semiconductor properties to move, bringing about a slight expansion in current, yet a lot bigger reduction in voltage. Outrageous expansions in temperature can likewise harm the cell and other module materials, prompting more limited working lifetimes. Since a significant part of the daylight beaming on cells becomes heat, appropriate warm administration improves both effectiveness and lifetime.
REFLECTION – A cell’s productivity can be expanded by limiting the measure of light reflected away from the cell’s surface. For instance, untreated silicon reflects over 30% of episode light. Hostile to reflection coatings and finished surfaces help decline reflection. A high-proficiency cell will seem dim blue or dark.
Scientists measure the exhibition of a photovoltaic (PV) gadget to anticipate the force the cell will deliver. Electrical force is the result of flow and voltage. Flow voltage connections measure the electrical qualities of PV gadgets. On the off chance that a specific “load” obstruction is associated with the two terminals of a cell or module, the current and voltage being created will change as indicated by Ohm’s law. Efficiencies are acquired by presenting the phone to a consistent, standard degree of light while keeping a steady cell temperature, and estimating the current and voltage that are created for various burden protections.