Before buying solar panels, you should take into account what type of solar photovoltaic system you need, assess their downsides, benefits, and typical scenarios where certain types would be the better than others.
The main characteristic of the solar panel is efficiency of solar energy conversion. Monocrystalline elements have the highest efficiency index, more than 20%. Polycrystalline panels have about 18% efficiency. A significant reduction caused by impurities of carbon, oxygen and other elements. Thin-film models show an efficiency of about 13%. And there are restrictions of the panels physical dimensions.
As you might have guessed, the cost of monocrystalline cells is higher than other panels when calculated per unit of power. The high cost of single crystals is associated with the complexity of technological purification of silicon. Polycrystalline panels are 15-20% cheaper, thin-film ones – 35% cheaper.
What to choose?
- High performance due to high purity silicon
- The performance of monocrystalline solar cells is 18 – 23%
- They are compact. High performance allows using a smaller area for the panel placement
- Long service life. Manufacturers guarantee that their products will last at least 25 years
- High price. These elements are significantly more expensive than other types, so building a system will require large capital investments.
- Acceptable cost. Easier method of manufacturing polycrystalline solar panels, makes their price much more attractive in the market
- Productivity. The efficiency rarely exceeds 14-18% due to low purity of silicon
- To achieve the estimated power you need have to install more batteries
- Sensitivity to high temperatures. Impurities in the polycrystalline cells worsen a temperature threshold, when certain chemical reactions begin to occur in them. This feature affects the battery life.
Panels with string ribbon solar cells are also made out of polycrystalline silicon. The name of the panel type comes from a manufacturing technology: temperature-resistant wires are pulled through molten silicon, forming very thin silicon ribbons. Such solar cells look similar to traditional polycrystalline solar ones.
- They use half the amount silicon as monocrystalline manufacturing. This contributes to lower costs
- The manufacturing technology is more costly
- Efficiency is around 13-14%
- The lowest space-efficiency of any of the main types of crystalline-based solar panels
- Low cost of production = low cost for the end user
- Pleasant aesthetics, formed by uniformity of silicon deposition
- Great heat resistance. At high temperatures, the film cells retain their original performance, so they are stable and versatile, suitable for a variety of climates.
- Require more space for installation
- It is required to install more batteries to reach the planned power, therefore you need more coverage area
- Additional expenses: costs associated with the purchase of supporting structures, cables and other consumables
- Short operational period
The output of electrical power is too low, cells are traditionally used for small-scale pocket-type applications. “Stacking” manufacturing technique builds several layers of amorphous silicon which results in higher efficiency (6-8%).
It is the only thin-film technology that has better cost-efficiency than crystalline silicon in a multi-kilowatt systems. The efficiency is about 9-11%.
Copper Indium Gallium Selenide
CIGS panels have great potential in terms of efficiency. They contain less amounts of the toxic cadmium than in CdTe solar cells. The efficiency is in the range 10-12 %.
Building-integrated photovoltaics combine several layers based on both crystalline-based and thin-film technology. In the future we may use roofs, windows, walls, facades, and many other things of photovoltaic material. For now, it is simply way too expensive for most homeowners.
See also our solar water heater article