• Energy Research

Abstract Using biowaste as a resource is required in order to meet the EU common objectives for waste management. Biowaste management should be considered from the economic, environmental, and social perspectives. The resulting complexity constitutes an important barrier to the implementation of biowaste planning projects. The goal of this study is to propose an effective tool to assess, compare, and select the best biowaste management alternatives for stakeholders. In order to reach research goal a methodological approach based on the combination of Multi-Criteria Analysis and System Dynamics method is proposed. The aim of the proposed method implemented in a modelling tool is mainly addressed to policy and decision makers specifically (1) to evaluate biowaste management options, (2) to assess the sustainability of bioenergy projects, and (3) to find an optimal solution for biowaste treatment given the conditions in a particular region. The proposed method can help to structure and assess complex problems while both responding to the interests of multiple stakeholders and avoiding the weaknesses of other evaluation techniques. The method has been applied to a case study involving the three Baltic States – Latvia, Lithuania and Estonia. The results obtained showed that separate collection and Anaerobic Digestion of biowaste is the best solution in all three Baltic States. Other acceptable options include incineration with energy recovery and Mechanical Biological Treatment with Anaerobic Digestion.

Abstract Using biowaste as a resource is required in order to meet the EU common objectives for waste management. Biowaste management should be considered from the economic, environmental, and social perspectives. The resulting complexity constitutes an important barrier to the implementation of biowaste planning projects. The goal of this study is to propose an effective tool to assess, compare, and select the best biowaste management alternatives for stakeholders. In order to reach research goal a methodological approach based on the combination of Multi-Criteria Analysis and System Dynamics method is proposed. The aim of the proposed method implemented in a modelling tool is mainly addressed to policy and decision makers specifically (1) to evaluate biowaste management options, (2) to assess the sustainability of bioenergy projects, and (3) to find an optimal solution for biowaste treatment given the conditions in a particular region. The proposed method can help to structure and assess complex problems while both responding to the interests of multiple stakeholders and avoiding the weaknesses of other evaluation techniques. The method has been applied to a case study involving the three Baltic States – Latvia, Lithuania and Estonia. The results obtained showed that separate collection and Anaerobic Digestion of biowaste is the best solution in all three Baltic States. Other acceptable options include incineration with energy recovery and Mechanical Biological Treatment with Anaerobic Digestion.

AbstractMember states of the European Union have undertaken to reduce GHG emissions and to achieve targets in 2020 and 2030. By using the system dynamic model, it is possible to analyze the possible GHG emission reduction, and the impact of suggested policy instruments on this reduction.

AbstractMember states of the European Union have undertaken to reduce GHG emissions and to achieve targets in 2020 and 2030. By using the system dynamic model, it is possible to analyze the possible GHG emission reduction, and the impact of suggested policy instruments on this reduction.

Active building envelopes that act as energy converters—gathering on-site available renewable energy and converting it to thermal energy or electricity—is a promising technological design niche to reduce energy consumption in the building sector, cut greenhouse gas emissions, and thus tackle climate change challenges. This research adds scientific knowledge in the field of composite building envelope structures containing phase-change materials for thermal energy storage. In this study, the focus lies on the cooling phase of the diurnal gain and release of solar energy. The experimental setup imitates day and night environment. Six alterations of small-scale solar facade modules are tested in two different configurations—with and without the adjustable insulation layer on their outer surface during the discharging phase. Modules explore combinations of aerogel, air gap, and Fresnel lenses for solar energy concentration. The results allow us to compare the impact of the application of an additional insulation layer at “night” for different designs of solar facade modules. The results show that modules with an air gap provide higher heat gains but do not take full advantage of the latent heat capacity of phase-change materials.

Active building envelopes that act as energy converters—gathering on-site available renewable energy and converting it to thermal energy or electricity—is a promising technological design niche to reduce energy consumption in the building sector, cut greenhouse gas emissions, and thus tackle climate change challenges. This research adds scientific knowledge in the field of composite building envelope structures containing phase-change materials for thermal energy storage. In this study, the focus lies on the cooling phase of the diurnal gain and release of solar energy. The experimental setup imitates day and night environment. Six alterations of small-scale solar facade modules are tested in two different configurations—with and without the adjustable insulation layer on their outer surface during the discharging phase. Modules explore combinations of aerogel, air gap, and Fresnel lenses for solar energy concentration. The results allow us to compare the impact of the application of an additional insulation layer at “night” for different designs of solar facade modules. The results show that modules with an air gap provide higher heat gains but do not take full advantage of the latent heat capacity of phase-change materials.

Abstract The article analyzes district heating system efficiency by using benchmarking system. The 26 biggest Latvian DH companies were taken as case study for analysis. Two main components were distinguished from existing district heating systems tariffs: cost of fuel in tariff and other costs. Non-linear regression model is used for benchmarking analysis. Equation, which describes other costs as dependent variable, whereas fuel part of costs in tariff as independent variable was obtained. Performance of Latvian district heating companies were evaluated by using various efficiency indicators describing systems technical, scale, dynamic and financial parameters. Data envelopment analysis was used for measuring efficiency of these companies by taking into account multiple factors. In order to indicate main parameters that influence heat energy tariff and efficiency of all district heating system, sensitivity analysis by using system dynamic model developed in previous study was carried out. The model finds out the possibility to introduce the 4th generation district heating system in Latvia. Model includes the transition of heat network to the low-temperature regime at 80% share of the renewable energy. Moreover, matrix with district heating system efficiency parameters, which are most vital for optimization, was made.

Abstract The article analyzes district heating system efficiency by using benchmarking system. The 26 biggest Latvian DH companies were taken as case study for analysis. Two main components were distinguished from existing district heating systems tariffs: cost of fuel in tariff and other costs. Non-linear regression model is used for benchmarking analysis. Equation, which describes other costs as dependent variable, whereas fuel part of costs in tariff as independent variable was obtained. Performance of Latvian district heating companies were evaluated by using various efficiency indicators describing systems technical, scale, dynamic and financial parameters. Data envelopment analysis was used for measuring efficiency of these companies by taking into account multiple factors. In order to indicate main parameters that influence heat energy tariff and efficiency of all district heating system, sensitivity analysis by using system dynamic model developed in previous study was carried out. The model finds out the possibility to introduce the 4th generation district heating system in Latvia. Model includes the transition of heat network to the low-temperature regime at 80% share of the renewable energy. Moreover, matrix with district heating system efficiency parameters, which are most vital for optimization, was made.