**2. Research Objects, Data Sources and Scope of Work**

The article analyzes anonymized data on the electricity consumption of customers from the C12 group running a business in the gastronomy and hotel industry. Hourly resolution data were provided by one of the Distribution Network Operators.

The research objects were in the south-west of Poland and were:


For the purposes of analyzing the insolation conditions in terms of the productivity of potential photovoltaic installations, the conditions in the vicinity of the capital of the Opolskie Voivodeship were assumed as the geometric center of gravity of the analyzed enterprises' distribution. The location of the Opolskie Voivodeship and the value of available solar radiation in relation to other regions of Poland are shown in Figure 3. The insolation data in the analyzed period were a set of hourly data of horizontal radiation values downloaded from the website [48]. Horizontal radiation is the sum of direct and diffused solar radiation. The above-mentioned data were extracted from the ERA5 database on an hourly basis.

Using statistical methods, the degree of similarity of the electricity consumption profiles in the analyzed enterprises was determined according to:


The calculation process was carried out in the RStudio environment (RStudio: Boston, MA, USA) on the hourly data of energy consumption in enterprises (Figures 4–10), hourly power demand in the National Power System (Figure 11a) and solar radiation conditions (Figure 11b).

**Figure 3.** Horizontal insolation in Poland (for horizontal surfaces) for years: 2010–2019 (numbers in black) and 2020 (numbers in blue). Source: own study based on references [48].

**Figure 4.** Course of hourly electricity consumption for the analyzed case study: (**a**) C1, (**b**) C2. Source: own study.

The analysis in Figures 4–10 shows the existence of certain differences in the course of the variability of hourly electricity consumption also within individual industries. These differences result, among others, from the characteristics and working hours of individual enterprises.

The horizontal blue bars indicate low electricity consumption on off-peak days, which is especially noticeable in C1, H2, R2 and R5. The work pattern adopted in other cases of enterprises results in the maintenance of a stable level of electricity consumption on a weekly basis, which is particularly visible in the case of C2 and R3.

The impact of restrictions introduced during the COVID-19 pandemic waves is particularly interesting. In all cases, except C2, the first lockdown in March 2020 is visible. The impact of the second lockdown in November 2020–January 2021, encompassing the "national quarantine" period, is visible in cases C1, C3, H3, R1–R5. However, in the cases of C1, H2, H3, R1–R5, the devastating effect of restriction is noticeable. A significant reduction in their activities is visible throughout the period from the second to the third wave of the COVID-19 pandemic.

**Figure 5.** Course of hourly electricity consumption for the analyzed case study: (**a**) C3, (**b**) H1. Source: own study.

**Figure 6.** Course of hourly electricity consumption for the analyzed case study: (**a**) H2, (**b**) H3. Source: own study.

**Figure 7.** Course of hourly electricity consumption for the analyzed case study: (**a**) H4, (**b**) R1. Source: own study.

**Figure 8.** Course of hourly electricity consumption for the analyzed case study: (**a**) R2, (**b**) R3. Source: own study.

**Figure 9.** Course of hourly electricity consumption for the analyzed case study: (**a**) R4, (**b**) R5. Source: own study.

**Figure 10.** Course of hourly electricity consumption for the analyzed case study: (**a**) R6, (**b**) R7. Source: own study.

(**b**)

**Figure 11.** Course of hourly electricity consumption for the analyzed case study: (**a**) Horizontal Insolation, kWh/m2/year (**b**) Load of Power System, GW. Source: own study.
