How to choose solar panels? Expert advice

The co-founder of the Generation Roman Kapuka tells about what photo panels are, how they differ from each other and due to which they work more efficiently.

A set of panels is the most expensive part of a solar installation. Therefore, their choice should be approached carefully. Today I want to share with you the knowledge based on my many years of experience and tell you which type of solar panels to choose, which brand to give your preference to and how to pre-check the components you are interested in.

Choice of technology: single crystal or polycrystal

Solar panels can be of three types:

  • monocrystalline;
  • polycrystalline;
  • film.

The first and second types are used as a component of solar installations. You should immediately decide which type of panels suits you best: monocrystal or polycrystal.

In the first, the wafers (modules) for the panels are grown as a pure silicon monocrystal.

In the second, the wafers are produced by conventional silicon melt casting.

This difference in structure determines their performance in the future. And that’s why:

  • single crystal plates have the highest efficiency, they can collect up to 21-23% of the energy of the light incident on them. However, the full efficiency of the modules occurs only in direct sunlight. In weak and diffused light, their recoil is noticeably reduced;
  • polycrystalline plates have lower efficiency, up to 17-18%, and catch scattered light a little better. In addition, their price class is cheaper compared to monocrystalline panels of the same power.

When making a choice, it is also worth considering the location, orientation and illumination of the site. In general, a single crystal will work more efficiently in almost any of the options.

If the budget is limited, but the area is sufficient, polycrystal is suitable for surfaces oriented to the East or West. When orienting to the North, the placement of SPP is not advisable.

Please note: the decision must be made taking into account not only the parameters of the panel itself. It is necessary to calculate the total output of all installation fields, and then compare the energy output for different types of panels. The result can be surprising, especially when comparing annual volumes. But I’ll talk about this a little later.

In film panel modules, a thin amorphous silicon film is applied to a special substrate. Their main indicator is low cost, as well as small size. But very low productivity and too short service life (2-3 years) do not yet make it possible to use this class of panels in “green energy”. Moreover, their already low efficiency begins to decline almost immediately due to the burnout of the battery film.

Manufacturer’s choice: price, quality, warranty and reliability

When comparing solar panel manufacturers, the first thing to consider is the following:

  1. The company’s position in the Bloomberg rating. This agency introduced a gradation of firms in this area, conditionally dividing them into three groups:
  2. tier1 – premium-level companies that own their own module development facilities and separate research laboratories, and manufacture on the best equipment with strict quality control.
  3. tier2 – companies in this group do not differ much from tier1, but for the most part these are new firms on the market that do not yet have a strong authority in business. They use not their own, but ready-made developments of other companies. Their investments in the development of production are more modest, but the cost of such panels is also lower.
  4. tier3 – basically, these are platforms for assembling panels from ready-made component materials.
  5. Availability of a guarantee. Most manufacturers provide a guarantee that after 25 years the panel degradation rate will not exceed 10%. But it is important to remember that it is respected as long as the company exists. Here, too, the tier1 and tier2 firms have the best prospects. In addition, it will not be superfluous to make sure whether there is a service center of the selected company in Ukraine.
  6. Price / power ratio. We divide the cost of the panel by the power and determine the cost of a watt for each of the manufacturers under consideration. Using this ratio, you can compare the real price of potentially generated energy from each panel and choose the option that is best for you.

Choosing a model for a specific object

The best option is an open, well-lit place. But do not forget that on very hot days the temperature can affect the efficiency of the panels. In such a situation, it is important to pay attention to the temperature coefficient and give preference to the model with its lower indicator. Polycrystalline panels will be more acceptable in such a situation. For areas in cool places, this moment can be ignored.

On the other hand, if your station is located in an area with more cloudy weather, its capacity may also decrease. To prevent the occurrence of situations when the SPP does not generate the planned volume, you can add an additional number of panels to the installation specifically to ensure the required production volumes in the off-season.