Solar energy is by far the most promising means of non-conventional sources of energy, next to Nuclear. At the present, you can find solar arrays on top of buildings like factories, offices & even residential structures. With the advancement in solar technology, people have even started to invest in solar power for homes. However, not everyone can afford big bulky solar PV panels on their roof, this is where thin film solar panels come in.
They light, flexible & most of all, they are affordable. They are the latest in the solar energy market, and they just might be the thing for you.
What are Thin Film Solar Panels?
As the name suggests, these are very sleek solar panels, and the average thickness of a solar cell on these panels can be less than a hair. Since they are thin, they require less material to make, thin film solar panels are also easier to make than traditional solar PV cells. Thus, they are cheaper as compared to traditional solar panels.
Due to their cost these types of panels can be applied in a wide variety of situations. More people are switching to a thin film solar power system, especially for personal use.
Different Classifications of Thin Film Solar Panels
There are 4-types of thin film solar panels, based on the materials they are built from. They all have different key properties, pros & cons.
So, let’s do a brief discussion & comparison between different types of thin film solar modules.
Amorphous Solar Panels
These solar panels are made from silicon, much like a traditional solar module. Although, where traditional solar modules use two layers of crystalline semiconductor wafers. These use a non-crystalline layer of silicon covered by plastic or glass. Several cells like these are layered over one another for an amorphous solar panel.
Pros
a) They don’t have toxic materials inside them, making them applicable in a variety of environments.
b) Contain less silicon, making them cost-effective. They can be applied to small appliances like calculators.
c) They are very flexible, making them more durable & resistant to damage.
Cons
a) They have very low efficiency when compared to traditional silicon solar panels, I.e., less than 50%.
b) You cannot use them to power larger loads, like homes.
Cadmium Telluride (CdTe)
Unlike the previous type of panel, these use cadmium telluride (CdTe) instead of silicon as a semiconductor. These are made from thin layers of CdTe surrounded by a layer of conductive material. A CdTe solar cell generates electricity using the photovoltaic effect and the conductive layer collects & transfers it to the battery/inverter, etc.
Pros
a) These can absorb shorter wavelengths of sunlight, compared to traditional crystalline solar panels.
b) Shorter wavelength light has more energy.
c) They cost less to produce than traditional panels.
Cons
a)Cadmium is an extremely toxic heavy metal. Making it difficult to dispose of these panels at the end of their life.
b)They are less efficient at converting sunlight into electricity, around 11%.
c)Tellurium is one of the rarest elements on earth, limiting the production of these types of panels.
Copper Indium Gallium Selenide (CIGS)
These are a type of flexible solar panels. They use a film of Copper Indium Gallium & Selenide, covered by layers of plastic, glass and conductive materials. These layers combined act as a semiconductor solar PV cell that generates electricity using sunlight. Due to the thinness of the layers and a flexible back cover, these panels are very flexible.
Pros
a) They are highly efficient (more than 20% efficiency), and they can compete with traditional solar arrays.
b) Cheaper than traditional panels.
c) May completely replace traditional panels in the future with further development.
Cons
a) Like CdTe, these also contain a small amount of cadmium, which is highly toxic.
b) More expensive than amorphous or CdTe panels.
c) Not environment friendly.
Organic Photovoltaic Cells
These are the last and the most interesting type of thin film solar cells. OPV (Organic Photovoltaic Cells) uses thin layers of organic vapour or polymers with an electrode on each end. When the sunlight hits the cell, it energizes the electrons inside the polymers, creating a potential difference between the electrodes.
Pros
a) They have an aesthetically pleasing quality, thus used in Building Integrated Photovoltaic applications.
b) These cells are made from materials that are abundant in nature, making them easier & cheaper to produce.
Cons
a) Like most other thin film solar cells, these are less efficient than traditional panels, with around 11% efficiency.
b) Due to its organic nature, the layers are in a constant state of degradation, leading to a far shorter lifespan.
How Do Solar Panels Work?
Solar Panels are the primary & most efficient form of harnessing solar energy. They work by converting solar radiation/sun rays into usable electricity, through a principle called the photovoltaic effect.
Before we dive deeper into the workings of solar energy, let’s discuss the components of a solar panel in a solar power system.
Components of Solar Panels
A solar panel have 4 basic components,
1. A layer of silicon/photovoltaic cells
2. Glass Casing
3. Metal Frame
4. Wires
The glass casing & metal frame are there to protect the Solar PV (photovoltaic) cells. The wires carry the current from a solar cell to the battery. The main component of a solar module is the solar cell, which is responsible for generating electricity. So, let’s discuss how it works.
How Does a Solar Cell Generate Electricity?
A solar cell uses the photovoltaic effect to generate electricity by harnessing energy from the rays of the sun. But how does it work & what is a solar cell made of? Let us find out.
Solar cells are made of two layers of silicon wafers, one positively charged & the other negatively. Silicon is a semiconductor, when sunlight hits the photovoltaic cells, the photons knock the electrons inside the semiconductor free. These electrons then start to flow from the positive layer to the negative layer, generating an electric current.
What are the Types of Solar Panels?
Now that you know the key information about thin film solar panels, let’s discuss in broader terms, the different classes of panels. There are three different classes of solar panels, depending on their structure.
Monocrystalline
These types of solar panels use two layers of silicon crystal wafers sandwiched together. Each wafer consists of a single silicon crystal. Single crystals the size of a solar cell are difficult & expensive to produce, making these the most expensive type of solar panels. However, due to the single crystal structure, these are also the most efficient at creating electricity.
Polycrystalline
These are the same as monocrystalline cells; the only difference is that each cell is made up of multiple crystals. The polycrystalline structure makes them cheaper to produce than monocrystalline panels but also makes them less efficient.
Thin Film
As discussed above, these do not use a silicon crystalline layer. Instead, they use layers of different semiconductors to create electricity using the photovoltaic effect. Due to their ease of production & different materials, the total cost of these panels is far less than traditional mono/polycrystalline ones. However, they are also far less efficient than them, except for CIGS panels.
Advantages and Disadvantages of Solar Energy
Solar power systems use the sun’s rays to create electricity without any pollution as a by-product. That sounds like a perfect solution to me, then why don’t we completely switch to solar? It’s not like the sun is going to run out anytime soon unless 5 billion years is a small time for you.
To be a lot of development need to do before completely adopting it. To make it easier for you to understand, let's check out the pros & cons.
Advantages of Solar Energy
a) 100% clean & requires less to no human intervention.
b) No moving parts mean no need for regular service or repairs.
c) Most solar panels have a very long operational lifespan, from 35 to 40 years.
d) Massively reduces electricity bills & dependence on the electric grid.
e) Solar energy can have very diverse applications, from homes to vehicles.
Disadvantages of Solar Energy
a)It is very difficult and expensive to recycle solar panels after the end of their lifespan.
b) They are very expensive; on average it takes 4 to 5 years for a solar power system to recover its cost. In India, the average cost of solar power for a home is around 2-3 lakhs.
c) A solar PV system depends on sunlight to create electricity. Thus, making them less efficient or useless in weather conditions with no sunlight.
d) Mounting a solar array requires a lot of space, with direct access to sunlight.
It is very expensive to store solar power for later use, due to the high cost of batteries.
e) It is very expensive to store solar power for later use, due to the high cost of batteries.
Frequently Asked Questions:
Q1. Are thin film solar panels better?
Ans. It depends on your application & budget. In short, thin film solar panels are cheaper than traditional silicon crystal panels. However, they are also less efficient than them.
Q2. What are the disadvantages of thin films?
Ans. There are some disadvantages of thin film solar panel systems:
a) They have low efficiency, around 11 to 13%.
b) They are not suitable for homes, because they need more space than available at most locations due to their lack of efficiency.
c) They have a shorter lifespan as compared to monocrystalline & polycrystalline panels.
d) They may contain toxic substances & heavy metals like cadmium.
Q3. What are 2 advantages of thin film PV panel?
Ans. Thin Film solar PV panels are increasing in popularity nowadays. This is simply, due to two things-
a) They require less material & are easier to build, therefore, they cost considerably less.
b) Capable of absorbing short wavelength sunrays, enabling them to absorb larger quantities of energy.
Q4. Why thin film solar cells are cheaper?
Ans. Unlike silicon crystalline solar cells, thin film panels need less material to produce. They also use simple manufacturing processes and are easy to scale. This enables thin film solar cells to be vastly cheaper than traditional solar panels.
Q5. What are the different types of thin film solar?
Ans. Thin Film solar panels come in 4-different classes, although they all use the same photovoltaic effect to generate electricity.
1. Amorphous
2. Cadmium Telluride (CdTe)
3. Copper Gallium Indium Selenide (CIGS)
4. Organic Photovoltaic (OPV) Cell
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