The essential part of the refractory materials production on a basis of sintered dolomite as raw material is the process of dolomite calcination. The technology process usually takes place in shaft or rotary kilns, where the dolomite stone, CaMg(CO3)2, is subjected to a high temperature heat treatment. The calcination of the dolomite is highly endothermic reaction, requiring significant amount of thermal energy to produce sintered dolomite (CaO, MgO), generating a large flow of hot gases at the furnace outlet. The objective of this work was to assess the possibilities of utilization of waste heat of exhaust gases from a shaft kiln in order to improve the overall energy efficiency of the technology process. Several different options were analyzed: (a) preheating of a raw material, (b) preheating of heavy fuel oil, (c) preheating of combustion air, (d) preheating of combustion air and raw material with flue gas, and (e) preheating of air for combustion and for drying of a raw material. Option (e) was selected as the most attractive and therefore it was analyzed in more details, showing significant annual energy savings and relatively short simple payback period on the investment.

Improvement of the energy conversion processes efficiency helps to achieve a more reliable energy supply, a cleaner environment, more competitive businesses, and higher living standard. Industry data indicate significant potential for improving the efficiency of steam systems and minimizing their operating costs by implementing various measures. The present work is a result of a systematic approach for energy performance analysis and identification of opportunities for optimizing the steam-condensate system of the combined heat and power plant ESM Energetika, Skopje, North Macedonia. The boiler plants provide superheated steam used in a hot-water station for the district heating system, for electricity generation, and as process steam for industrial customers. As the main operating costs of the plant stem from the natural gas consumption, the implementation of a set of energy efficiency measures will lead to its reduction, accompanied by less environmental impact. As a result of the system analysis, a number of energy efficiency measures have been identified. For each measure, the impact on individual parts of the system, as well as on the system as a whole, is evaluated using the steam system modeller tool. This paper elaborates some of the identified measures that are considered more reliable from an operational and financial aspect, mainly focused on steam production for the district heating system. Based on a conservative approach, significant potential for savings of natural gas, electrical energy, and treated water is estimated, which will lead to annual financial savings of about 245000 Euro.

The paper investigates the potential of biomass pyrolysis as a sustainable and renewable energy solution. The study focuses on three biomass types: corn cob, vine rod, and sunflower, which are abundant agricultural residues with potential for biofuel production. The pyrolytic gas, oil, and char produced during pyrolysis at a heating rate of 10 °C/min were analyzed. At the pyrolysis temperature of 500 °C, the corn cob showed the smallest final residual mass of 24%, while the vine rod exhibited the largest mass loss of 40%. Gas analysis revealed the concentrations of CO₂, CO, H₂, and CH₄ in the pyrolytic gas, indicating its energy potential. Sunflower presented the largest calorific value of the produced biogas, while corn cob was the lowest. The chemical composition of the bio-oils was determined, with aliphatic acids identified as the dominant compounds, suggesting their potential for biodiesel production. Fourier Transform–Infrared Spectroscopy (FT-IR) analysis of raw biomass and char products demonstrated varying extents of decomposition among the biomass samples. A multicriteria assessment approach was employed to evaluate the differences between the selected three biomass feedstock and determined that sunflower biomass ranked the highest among the three, although the overall difference was small, confirming the suitability of all three biomass samples for pyrolysis conversion to higher-value-added fuels.

Given the variable nature of wind speed and the importance of accurately determining the energy that can be generated at a given site, understanding the wind speed at different time scales is crucial. In addition to differences within a very short period (i.e., hourly and daily), these changes are also pronounced throughout the seasons. They are affected by the atmospheric conditions and the terrain's complexity. Therefore, this study investigates the seasonal wind speed variability and its impact on the potential energy generation in a representative study case of Koznica, the mountainous region in Kosovo. The wind speed measurements campaign started in May 2019 and ended in April 2020; the measurements were made at a 10 min time scale. Ground measurements show that the wind direction is mainly northwest and southeast. Then, the wind speed and potential energy generation variability analysis were conducted for three different measurement heights. The results show that winter and spring have the highest potential wind energy capacity with an average speed of 6.7 m/s. In comparison, the average wind speed is 6.12 m/s. Potential energy generation for each season (i.e., spring, summer, autumn, and winter is as follows: 64,396.7, 22,040.3, 42,539.3, and 46,417.2 MWh/year, respectively, while the average capacity factor is 25%. Solution-oriented findings from this study might provide valuable insights to policymakers and investors regarding wind power energy exploration in Kosovo and other places with similar geo-climatic conditions.

Among the current challenges facing the energy sector is finding environmentally friendly and high-performance forms of energy generation. One such form of energy generation is from the wind. In addition to the fluctuations that cause changes in the generated energy, another factor that significantly affects the overall efficiency of wind farms is the distance between the turbines. In that context, a distance of at least three diameters (3D) onwards is necessary to enable a stable operation. This is more difficult to implement for mountainous terrain due to the terrain configuration’s influence, the turbine units’ positioning, and the mutual influence resulting from their position in the area under consideration. This work investigates the interdependence of the terrain features, the placement of ten turbines in different scenarios, and the impact on the overall efficiency of the wind farm. The place where the wind farm is considered is in Koznica, a mountainous area near Prishtina. An analysis has been carried out for two-diameter (2D), three-diameter (3D), and five-diameter (5D) turbine blade spacing for turbines with a rated power of 3.4 MW. The study considers placement in the following forms: Arc, I, L, M, and V. The results show that for 2D distance layout, the capacity factors for Arc, I, L, M, and V placements have the values: 32.9%, 29.8%, 31.1%, 30.6%, and 37.1%. For the 3D distance, according to these scenarios, the capacity factor values are: 29.9%, 30.8%, 30.4%, 29.3%, and 35.6%. For the longest distance, 5D, the capacity factor values are: 28.9%, 29.9%, 29.4%, 27.6%, and 30.6%. The value of the capacity factor for an optimal layout; is achieved at 39.3%.

The continued expansion of cities in economic, population and geographical terms leads to significant environmental and infrastructural pressures, including the need for efficient municipal solid waste (MSW) management. This research focuses on the characterization of MSW generated in the city of Skopje and the investigation of its thermo-physical properties and energy utilization potential. The analyses cover physical and chemical properties, including density, moisture content, volatile matter, ash, and higher heating value, using adequate testing methods. The results indicate that MSW has a relatively high gross calorific value, surpassing typical MSW ranges comparable to those of solid fossil fuels. With approximately 79.42% volatile matter and a low ash content of 7.76%, the considered MSW demonstrates excellent combustibility. Chemical analysis reveals high carbon (53.12%) and hydrogen (7.69%) levels, supporting high energy value, while low nitrogen (0.84%) and sulfur (0.26%) levels ensure minimal NOx and SOx emissions. These characteristics position MSW as a suitable feedstock for energy production in incineration facilities. However, the heterogeneous composition of MSW presents challenges to process stability, necessitating prior waste preparation. The research concludes that harnessing waste energy potential could contribute to sustainability, reduce reliance on fossil fuels, and improve the environmental conditions in large urban areas.