# Evaluating Cybersecurity Risks of Bulgaria's Energy Sector: Focus on PV and HVAC-R
## 3 The Bulgarian Energy System--Current State, Issues, Trends, and Prospects  
### Energy Balance  
The Bulgarian energy system is part of the European energy system and its development, despite its purely Bulgarian specifics, is ultimately predetermined by the pan-European energy policy. The data presented here are for the Bulgarian energy system, as the authors know it best, but the forecasts for future development apply to the entire European Union. This statement can be supported by publications by other European [68] and Indian [69] researchers who have come to similar conclusions. The generation and consumption of electricity in the country over the last 10 years are presented in Figure 1. Electricity consumption remains constant within 5% with no discernible trend. Energy generation has been decreasing over the past 3 years due to the increasingly unfavorable conditions under which coal-fired power plants operate. The statistics on generating capacities are more insightful, particularly on the share of PVs in the total production. The growth of PV power plants over the last 10 years is shown in Figure 2 with the growth of the total installed capacity in the top plot and the share of PVs of the total installed capacity of all power plants in the country in the bottom one. Only PV power plants connected to the energy system are included in this statistic, so the actual installed PV power is even larger. The significant increase in the number of photovoltaic power plants, constructed over the past 3 years, has created a trend that appears to be set to continue in the near future. The increased construction of PV power plants is associated not only with specific measures to promote renewable energy sources but also with the significant price drop of all PV equipment, thus providing sufficient profit margins. The change in the price of PV panels is shown in Figure 3. The data are from the authors' own statistics and represent the average price per Watt-peak. The price increase in 2022 is due to logistics problems, supply chain disruptions, and the corresponding increase in transport costs that were intrinsic to that particular period in time. The average annual electricity price on the Independent Bulgarian Energy Exchange (IBEX) [70] is also shown in the same figure on the right-hand axis. The increasing difference between the electricity purchase price and the cost of PVs is a key factor in the growth of the installed capacity. Figure 1: Bulgarian annual electricity consumption and generation in 2015–2024. Figure 2: Growth of PVs in Bulgaria in the period 2015–2024. The top plot shows total installed PV power, while the bottom plot shows the percentage of the total installed power in the electric power system. The photovoltaic plants built over the last three years are mainly large-scale, concentrated facilities with a MW capacity. Although PVs account for almost one-third of the total generating capacities, the share of photovoltaic energy in the total annual electricity production is quite modest, as presented in Figure 4.  
The relatively small share in total energy production is due to the low annual hourly utilization of photovoltaics and the large number of winter cloudy days. Large photovoltaic capacities that operate without the ability to store energy create operational problems. There are intervals of the day (on sunny days with reduced consumption) in which there is excess power that needs to be balanced. The hourly change in the load of the entire energy system of the country on 7 May 2024 is shown in Figure 5. This is the day with the lowest consumption throughout the year (data from the Energy System Operator [71]). The simulated results for the energy generated by 4.6 GW of PV power plants, already operating in Bulgaria, are also shown in the same figure. The simulation used data from the EU Photovoltaic Geographical Information System (PVGIS) [72], which provides statistics on the performance of photovoltaic systems since 2005.