What do investors not think about when choosing high power solar modules?

We are typically accustomed to thinking that the more powerful the solar module, the cheaper the project will be in the end.

However, this is not always the case in practice when considering indirect factors affecting the power-to-price ratio.

Today, we receive inquiries for the construction of solar power plants (SPPs) for green tariffs or for the company’s own needs.

In the first case, it will be important for the customer how quickly they will recover the invested funds and how much they can earn by the end of the green tariff period.

In the second case, the owner will primarily be concerned with the power of the SPP and the resulting savings.

The first questions asked by customers at meetings are: I have an area of n hectares, how much can be built? What power can be installed on this roof?

Thus, the first thing that limits the power of the future plant is the existing area for installation. For green tariff projects, it is more about the allowed capacity for connection to the power grid.

The next question usually is: how much will it cost?

The customer already has or is in the process of forming a budget they are willing to spend to achieve profit or savings, and this is our next constraint when choosing a product.

Usually, questions about whether it is necessary to reinforce the roof’s supporting structures, how costs for metal mounts and module installation change with different models, the module’s service life, and its performance changes, and most importantly, which module will generate the most electricity given the project constraints set by the investor, are often overlooked.

We wrote about the advantages of rooftop solar stations in the previous article here.

The increase in module power, say from 395 W to 650 W, has occurred due to a significant increase in their sizes, for our example from 1.85×1 m to 2.4×1.3 m.

Applying simple math, we see that a 395 W module provides 213 W per m2, while a 650 W module provides 210 W per m2.

Next, let’s take a small roof area of 1200 m2 and the calculations above, and we can build 255.6 kW with 395 W modules and 252 kW with 650 W modules, and possibly even less if the roof is narrow and the more powerful panels cannot be accommodated. As a result, a module with smaller dimensions and power will generate more electricity, return the investor’s funds faster, and therefore be a more economically advantageous solution.

Manufacturers note that with more powerful modules, system balance costs can be reduced, as fewer mounting materials are needed since the number of panels decreases. For the same 1200 m2 roof, 648 modules of 395 W or 384 modules of 650 W will be needed. However, having fewer 650 W modules does not necessarily mean savings, as the larger size and weight will require one and a half times more metal mounts, and the risks of damage during installation also increase, which is offset by the increased price of related services. Additionally, transport risks need to be considered, as the pallet size is significantly larger, weighing about 1 ton, requiring special equipment for unloading, which will also be more expensive.

For small roof or land areas, we recommend considering less powerful modules, as they will generate more profit compared to the dubious savings from powerful modules.

However, for large industrial projects, choosing larger modules can be economically advantageous; the power-to-price ratio should be individually assessed for the project.

If the choice still comes down to the most powerful model, we are ready to offer an alternative n-type TopCon technology, which, according to the manufacturers’ forecasts, will become mainstream next year. The innovative development has achieved a power increase of over 20 W without changing the module size, which is significant considering that annual growth has usually been limited to 5 W or simply increasing the product size to achieve the necessary power. In addition to increased efficiency per m2, the technology has improved temperature coefficients, reducing generation losses, cut power degradation from 15.2% to 10.6% over 25 years of service, and added 5 years of additional degradation warranty, resulting in a total of 30 years.

The technology is somewhat more expensive than the standard p-type PERC, but even the price factor, according to our calculations, does not affect the final result, which manifests as higher efficiency, better generation over 25 years, and greater profit.

At Unisolar, we implement rooftop and ground-mounted solar power stations of varying capacities, offering high-tech efficient solutions for various customer needs.