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Crop residues could provide a local, sustainable, and low-cost solid fuel alternative to woody biomass for heat supply in the agricultural community. However, utilization of crop residues on a small scale is associated with increased pollutant emissions, as well as ash-related operational problems. There is ongoing research on fuel conditioning measures, such as fuel leaching, fuel blending, and using mineral additives, as a manner to mitigate these issues. The purpose of this study is to investigate the applicability of additives in the combustion of crop residues under everyday conditions. To this end, wheat straw pellets were combusted in a 30 kW boiler with and without additives (kaolinite and MgO, 2 wt. % and 4 wt. %). Carbon monoxide (CO) and particulate matter (PM) emissions have been monitored during combustion experiments, as well as changes in bottom ash behavior and composition. The results have shown that additives slightly decrease the heating value of the fuel (3%–6%). During experiments with additized wheat straw pellets, higher emissions of CO were observed. Combustion of pure not additized wheat straw pellets resulted in a PM emission of 568 mg/Nm3, which decreased with additives. Both researched additives increase the four characteristic ash deformation temperatures. [ABSTRACT FROM AUTHOR]

Energy goal of Serbia is to reach the share of 27% renewables in its final energy consumption by the year 2020. Geothermal energy is the source that can significantly contribute to the achievement of this goal, particularly in the domain of direct utilization. Indjija municipality is located in the northern part of Serbia and is a typical representative of a region in the Pannonian Basin. In Indjija municipality two exploration boreholes are drilled. Conducted analysis has shown that one of them (Indj-3/H) did not achieve expected results and was labeled as negative. The second (Indj-1/H) was labeled valid for the evaluation of prospective use of geothermal fluid. The results have shown that around 1.25×10 6 m 3 of water can be obtained annually from the second drill. With complete effusion in the drill Indj-1/H, a total of 10.85 GWh can be expected annually. The aim of this paper is to evaluate the geothermal energy potential of Indjija municipality based on two exploratory drill sites. Firstly, geomorphological, geological, geophysical, hydrogeological and hydrothermal characteristics of the area are determined. In addition to this, physicochemical characteristics of geothermal and mineral waters, as well as drill׳s capacity are analyzed. In accordance with the results, possible applications of the geothermal fluid are considered and recommendations for direct use are given. Feasibility study was conducted for a combined multifunctional system. Investment is profitable after 3–5 years depending of the scenarios. It is concluded that balneology, spas, sports and tourism activities, as well as sanitary hot water supply and space heating are the most appropriate forms for direct use. [ABSTRACT FROM AUTHOR]

Energy has an essential role in the socio-economic development of a country, therefore reliable and sustainable energy supply is a prerequisite for its prosperity. Strategies that analyze and predict energy demand in the future emphasize that local, renewable and sustainable energy sources should be in the focus of interest. Autonomous Province (AP) Vojvodina is a northern part of Republic of Serbia and an energy-deficient province. Crop residues represent the most abundant and promising biomass type for sustainable energy production in agricultural regions, including Vojvodina. Biomass is most commonly utilized through combustion for heat generation. The aim of this paper is to give an overview of total solid biomass potential (from agriculture, fruit and vine growing, forestry and wood processing) for energy generation in AP Vojvodina. Although this potential was initially estimated at 6.45 Mt per year, after considering all the influencing factors, it was concluded that only 2.45 Mt could be used for energy purposes. Solid biomass potential is equivalent to around 0.8 Mtoe per year and is sufficient to substitute completely solid and liquid fossil fuel consumption in Vojvodina, according to final energy balance of AP Vojvodina. [ABSTRACT FROM AUTHOR]

Combustion of wheat straw was investigated in a fixed-bed reactor for two air flow rates, 1,151 and 2,125 kg/m2h. Measured temperatures, mass loss, and gas composition were used to evaluate the combustion characteristics in terms of ignition front speed, burning rate, and quality of combustion in general. At lower value of air flow rate difference between the ignition rate and burning rate was significant, which can be easily noticed by the measurement results. At higher value of air flow rate, there was still a small difference between the ignition and burning rate, while the content of oxygen in the flue gas was 10%, which leads to the conclusion that a change in the method of delivering the combustion air is necessary. [ABSTRACT FROM PUBLISHER]

Geothermal heat pumps have several advantages over conventional heating and cooling systems. They can operate in both winter and summer, have high efficiencies, and do not directly emit any greenhouse gases during operation. Investors (in developing countries) can use Clean Development Mechanism as a source of financing for new or existing renewable energy facilities by selling Certified Emission Reductions credits (CERs), which represent the amount of CO2 emission (1 CER¼1 tCO2eq) that is avoided using renewable energy. The aim of this paper is to analyze the possibility of CO2 reduction by using geothermal heat pumps for fossil fuel displacement with applying Clean Development Mechanism. Results have shown that by using geothermal heat pumps during a 7-year crediting period, the estimated emission reduction would be 79.45 tCO2 (equal to 80 CERs), enabling the investor to achieve profit from selling 80 CERs and thus helping to fund the proposed project activity. Three main factors which influence the amount of CO2 reduction have been identified: carbon-dioxide emission factor for electricity source, efficiency of technology used for baseline scenario, and coefficient of performance (COP) of heat pumps. [ABSTRACT FROM AUTHOR]

Abstract: The interest in increasing the participation of renewable energy sources (RES) in energy production arises with increasing population and growing demands for energy production and consumption, as well as the fact of the limited fossil fuels reserves. RES in the energy balance of any country has their share of energy, socio-economic and environmental benefits. Investment in energy sector in the RES domain enables Vojvodina Province to reduce energy dependence on the fossil fuel market. From the total RES potential in Vojvodina Province that is 1293ktoe/year, around 1.7% is located in existing geothermal sources. There are 73 drills with a total capacity of 72.6MW from which 65 drills are tested positive. Currently, 15 wells are in production, with a total power of 17.7MW. There are 27 drills that have never been in production and which are perspective, with a total power of 42.8MW. The aim of this paper is to perform data analysis of direct geothermal energy utilization according to the water temperature and geothermal fluid flow. According to the results of the analysis recommendations for geothermal energy utilization are given within certain sectors: agriculture (aquaculture and greenhouses), heating of the facilities and pools, industrial applications and balneology. [Copyright &y& Elsevier]