Natural Resources and Technology

GEOCHEMICAL DISTRIBUTION OF ELEMENTS IN WATERS AND SEDIMENTS OF PLESENSKA RIVER WITH A SPECIAL FOCUS ON THE PRESENCE OF HEAVY METALS

Marjan Gorgievski — 2025-05-31

This paper presents the data from laboratory examinations of water and sediments in the autumn and early spring (September 2024 and February 2025). The examinations included waters and sediments from Plesenska River and the confluence of Kiselica River with Zletovska River, as well as a spring located in the immediate vicinity of Plesenska River. The water examinations were conducted to assess the actual condition and geochemical distribution of elements during the two studied periods, with a special focus on the presence of heavy metals. To obtain additional information about the components transported by the water flow and to gain insight into the cause-and-effect relationships and mechanisms, sediment examinations were also performed. The results obtained from the laboratory tests of water and sediments were analyzed in details, and correlation diagrams were made with interpretations of the findings.

TECHNO-ECONOMIC ANALYSIS AND COST-EFFECTIVENESS OF PHOTOVOLTAIC SYSTEMS FOR RESTAURANTS IN MACEDONIA

Sara Aneva — 2025-05-31

The technology of photovoltaics is constantly improving with increased efficiency and effectiveness, enabling lower investment and operational costs, as well as comprehensive solutions to address challenges such as mitigating price shocks and reducing dependence on fossil fuels. This, in turn, contributes to environmental protection by avoiding carbon dioxide emissions when compared to a power plant of the same installed capacity that uses fossil fuels as its energy source.

This paper presents a techno-economic analysis for the installation of a photovoltaic (PV) system on an average restaurant in Macedonia. The objective is to determine the feasibility of a photovoltaic system for an average restaurant that procures electricity from the open market, with the goal of reducing the energy dependence of restaurants and encouraging investments in PV systems by these commercial entities. Such investments can significantly contribute to increasing domestic electricity production from renewable energy sources.The analysis is based on the electricity consumption of an average restaurant and the electricity production from a PV system with a total installed capacity of 40 kWp, simulated using PV*SOL premium software. By comparing the hourly electricity production from the photovoltaic system, obtained through PV*SOL premium, with the hourly electricity consumption of the restaurant, derived from the standard load curve for restaurants, a techno-economic analysis was conducted in accordance with the forecasted electricity prices on the open market, taken from the HUDX electricity exchange. The analysis also considers the cost of the photovoltaic system, as well as its operational expenses.

COMPARATIVE ANALYSIS OF ENERGY EFFICIENCY AND ECONOMIC SUSTAINABILITY IN PUBLIC BUILDINGS: A CASE STUDY OF A KINDERGARTEN USING HEAT PUMPS AND PHOTOVOLTAIC SYSTEMS

Sara Aneva — 2025-05-31

Energy efficiency improvements and renewable energy integration in public buildings represent a significant step toward reducing operational costs and minimizing environmental impact. This study presents a comprehensive analysis of the energy performance of a kindergarten in Macedonia, with a total area of 1 200 m², an annual electricity consumption of 25 000 kWh, and a yearly consumption of 16 700 liters of extra light fuel oil for heating. The objective is to identify the most efficient and cost-effective solution by comparing three scenarios. The first scenario considers the current situation, where electricity is procured from the Universal Supplier, and heating relies on extra light fuel oil. An alternative option is analyzed, considering electricity procurement on the free market. The second scenario involves heating with a 150 kW heat pump powered by electricity procured from the free market and the Universal Supplier. The third scenario includes the installation of a 40 kWp photovoltaic (PV) system on the kindergarten's roof, utilizing the generated electricity for self-consumption, selling surplus electricity, heating with a 150 kW heat pump, and procuring additional electricity as needed. The study evaluates the return on investment (ROI) and operational cost savings for each scenario, with and without accounting for the reduction in CO₂ emissions based on the European carbon pricing mechanism. The results demonstrate the economic feasibility and environmental benefits of transitioning to renewable energy and energy-efficient heating systems in public institutions.