*5.2. Photovoltaic Systems*

Private investors, especially prosumers, have noticed the advantage having of PV systems in Poland. Installed capacity in photovoltaics at the end of 2020 was almost 4 GW, which means a 200% increase year on year. According to experts, PV is one of the most flexible systems to establish many ecological distributed powerplants. Its growth was exponential and could be described with the Equation (10). The R<sup>2</sup> indicator—0.9672 was very high in that case and showed that the curve equation had described the analyzed data very well (11) (Figure 7).

$$y = 8E - 5\mathfrak{c}^{1.0858x} \tag{10}$$

$$\mathbf{R}^2 = 0.9672\tag{11}$$

The experts make a remark that, unfortunately, the situation on the PV systems market is highly dependent on politicians' decisions. Currently, there is information that the rules for collecting energy from prosumers will change dramatically; investing in PV systems will be unprofitable for the prosumers.

According to the Energy Regulatory Office, the number of photovoltaic installations at the end of 2020 was around 460,000. The average capacity of the installed PV system was 5.78 kWp. Photovoltaic installations account for 99.89% of all RES micro-installations. Since 2018, the share of monocrystal PV systems has hit 98% in the year-to-year sales.

**Figure 7.** Photovoltaic systems—installed capacity (MW) and trends.

The PV systems have tremendous potential for growth. It is estimated that there are 5,522,000 residential buildings in Poland that are suitable for PV systems. The size of the average roof of a residential building is about 100 m2. That gives about 552,200,000 m<sup>2</sup> of estimated area for PV systems to be installed. The total area could be from 182.23 GWp capacity installed from silicone PV systems to 662.24 GWp from hybrid or perovskite PV systems. That potential could be even more considerable because PV systems can also be installed on facades.

It is estimated that the PV system could fulfill from 4.0 to 10.0% of electricity demand in Poland.

The efficiency of PV systems could be upscaled 2–3 times by combining them with heat pumps, depending on the COP of the heat pumps.

The conclusion from the weighted SWOT matrix for the photovoltaic systems in Poland (Table 4) was also not very optimistic as for the weighted SWOT matrix for the Polish energy sector presented in Table 3. The internal factors ratio (IFR) was above one, meaning that the strengths were more critical than the weaknesses. The opportunities to threats ratio was 0.86, which means that the photovoltaic systems' development perspectives are not favorable because of extreme dependence on political decisions. The balance between the IFR and EFR was 1.10:0.86. The Polish policymakers' only strategy should be to not disturb the private sector and to provide energy distribution grids to handle the new installations. As shown in Figure 7, Polish private investors are very eager to build PV systems and understand the need to convert to a "zero-emissions" policy, but they have to see an economic reason to do it.

This vital activity should also be able to provide affordable and effective solutions to store energy, which requires further research and funding.
