**4. Results**

## *4.1. Results of PV Electricity Production*

Based on MERRA-II data for the town of Łask near Łód ´z, a map chart of the intensity of solar radiation falling on the horizontal plane and a map chart of the outside temperature were drawn, as shown in Figure 7.

**Figure 7.** Weather data for the centre of Poland according to the weighted power of photovoltaic installations created under the "My Electricity" program, data for 2019: (**a**) solar radiation intensity on the horizontal plane; (**b**) outdoor temperature.

Similar data from the MERRA-II website were collected for all province capitals in Poland. Based on the data on the intensity of solar radiation and the outside temperature, detailed calculations of electricity productivity were made using Equations (1)–(5). There is no archived information on the arrangement of the panels in the databases relating to the "My Electricity" program, and therefore, it cannot be assumed that all installations are located in terms of ensuring maximum energy gains per year. The calculations used data on the total annual intensity of solar radiation registered on the horizontal plane (insolation).

The calculation results for each province in Poland in terms of insolation, yearly unit production electricity from PV (YUPVP), and the average annual temperature are presented in Table 1.


**Table 1.** Insolation, yearly electricity productivity, and yearly average temperature outside per province. Authors' study based on [66].

YUPVP'—yearly electricity production directly from MERRA-II database [66].

The highest value of insolation in relation to m2 of the panel area per year was obtained for the Lesser Poland Province, as 1257 kWh. Additionally, the highest productivity was found for the Lesser Poland Province (1104.32 kWh/kWp/year), and the lowest for the Warmian-Masurian Province (1025.71 kWh/kWp/year). The obtained values of yearly electricity production (YUPVP) were similar to the results presented by MERRA-II (YUPVP'). The convergence of values was greater than 99% (difference YUPVP and YUPVP' < 1%).

On the basis of Formulas (5) and (6), electricity productivity was calculated in the first year and over 30 years. Based on information on the amount of co-financing for each province (DI), the cost of co-financing electricity production was calculated per 1 MWh. The results are presented in Table 2.

In the perspective of 30 years, the production of 1 MWh of energy from PV was subsidised in the amount of approximately 6.52 EUR on the national scale. The highest amount was co-financed for installations in the Podkarpackie Province (7.46 EUR/MWh), and the lowest in the Opolskie Province (5.78 EUR/MWh). The differences in the amount of co-financing result from weather conditions, as well as the average size of installations in individual provinces.


**Table 2.** Globally electricity production and dotation per MWh per province.
