Photovoltaic Cells: Pros and Cons of Crystalline and Thin Film Solar Panels
It’s the PV Cell Title Fight of the Century!
If you’ve done any sleuthing into solar energy, you know there are several types of solar photovoltaic cells (PV cells) now available to consumers.
“Photovoltaic” means the cell turns the sun’s energy into electricity.
But what’s best for your needs? Whether you own a home, business, or farm, the type of panels you install depends on your own priorities, the specific features of your land, and your cost limits.
This article will help you compare crystalline and thin film photovoltaic cells – the two main categories of PV cells on the market today.
The Main Event: Two Types of PV Cells
In One Corner: Crystalline Silicon (c-Si)
Crystalline silicon solar panels have two varieties – mono-crystalline and polycrystalline (also known as multi-crystalline). These are actual silicon crystals that convert solar energy into electric power – a process that happens naturally for certain materials. How it works is, the sun’s energy frees electrons and gives them the ability to travel through circuits. For a full explanation of solar power at a 6th grade science level – of how solar energy works, go here. Very fun stuff!
PV cells create what’s called DC power – direct current. Most home appliances use AC power – alternating current. To bridge this gap, you need an inverter as part of your solar installation.
You’ve probably seen crystalline panels in photos since they’re the most common variety in use. Coastal Solar installs both types – mono and polycrystalline.
You can identify them by the layout of the cells. See the photos here.
Mono-crystalline PV cells are circular, and polycrystalline cells are rectangular. Mono-crystalline are the most efficient and highest performing solar cells on the market, though they are also the most expensive. They also perform better at higher temperatures than the polycrystalline ones.
Polycrystalline cells are less wasteful during the manufacturing process, and thus more affordable. Some people also consider them less “attractive,” but of course that really depends on your personal tastes.
Both types of crystalline silicon PV cells have similar advantages over thin film cells. See the PV Cell Title Fight below for 7 reasons you would choose crystalline over thin film.
In the Other Corner: Thin Film
They’re called thin film because… they’re thinner. Originally, this was pretty similar technology and still used silicon. The most common place you’ve seen this is on solar powered calculators. That thin little window that reacts not just to sunlight, but even to indoor lights, is a thin film silicon photovoltaic cell.
Without getting too “sciencey,” the main difference is what the “light absorbing” material is mounted on. For crystalline, it’s usually some type of tempered glass, which is harder to break. For thin film, layers of the material are poured onto either plastic, metal, or glass. These layers are about 350 times thinner than the crystals used in c-Si cells.
Today, there are actually three viable types of thin film PV cells available. These include amorphous silicon (a-Si), cadmium telluride (CdTe), and the latest innovation, copper indium gallium deselenide (CIGS). Of these, silicon is the worst choice for larger uses. It works well for calculators and similar small uses, but not as well for larger ones.
So when we look at the advantages for each type of PV cell, we’ll also note some of the differences between these. Below you’ll find 7 reason to choose thin film PV cells over crystalline.
PV Cell Title Fight – Which One Wins?
Let’s take a look at what each type of PV cell has in its favor:
Crystalline Silicon Advantages:
In the ‘boxing’ metaphor, c-Si has a longer reach and greater stamina than thin film cells. Here’s what that means:
- Largest Market Share. This matters because they’re easier to find. A lot of thin film manufacturers have gone out of business too as it’s still an evolving technology.
- More Efficient. Estimates vary by brand and by type, but recent advances have pushed c-Si panels to over 20% efficiency. Most thin film varieties are closer to 10%, though the CIGS versions are outperforming the others and are closing the gap with crystalline. This matters because if you choose thin film, you’ll need more panels to get the same power output. If you have a smaller roof, this becomes problematic.
- Longer Lasting. 30 years is common, and you will see a lot of 20-25 year warranties. Some estimates say crystalline panels may well produce useful levels of electricity for up to 50 years.
- Minimal Power Losses. C-Si cells only lose about 1% in power output each year. Thin film is similar, but that’s after a 20% initial loss that happens the first time it’s exposed to the sun.
- More Resistant to Breakage. Tempered glass protects the crystalline cells and helps them withstand flying debris in a windstorm, for example. Thin film won’t work on tempered glass, and flat glass is more fragile. That said, thin film can be applied to other surfaces too, like plastic and metal, making it more durable as well.
- Non-toxic. One of the major reasons to use solar is to protect the environment. If you use CdTe thin film cells, you’re using a toxic material (cadmium) that is hard to dispose of safely. Crystalline silicon does not harm the earth.
- Sinking Costs. The costs for silicon are coming down, which makes crystalline PV cells ever more affordable.