Search

Islands have increased potential to integrate renewable energy sources (RES) into their energy systems and shift towards sustainable decarbonization. The intermittent electricity causes issues such as the mismatch between the energy demand and supply, the grid instability and the electricity price volatility. The integration of the battery-powered electric ferries (BEF) into the isolated energy system (IES) powered with RES can be considered as an economically and environmentally friendly solution for matching the demand with the supply, since all-electric ships can connect to the grid and provide positive or negative balancing power. The carbon dioxide (CO2) emissions from shipping operations can be reduced to zero by utilizing batteries as a power source. This paper deals with a holistic approach that demonstrates opportunities that implementation of BEF offers in the framework of IES of an island. A method for modelling energy supply for a 100% electric ferry transport is developed to reduce the critical excess electricity production (CEEP) from the photovoltaic (PV) power systems. The energy modelling of the IES was carried out in EnergyPLAN program. The results confirmed that synergy between the PV power systems and BEF can significantly reduce the CEEP, the operating system costs and the emissions of CO2.

Value waste chain generates a significant amount of different agricultural wastes, co-products and by-products (AWCB) that occur during three major stages of a complex path, from farm to fork. This paper presents stages where and how waste occurs along the path from the ground to the table for a period of 7 years, from 2010 to 2016 in the 28 member countries of the European Union (EU28). Considering the specific conditions of the EU28 community, four different sectors with 26 commodities and waste types that occur in those sectors were analysed: 5 commodities in the Fruit sector, 10 commodities in the Vegetable sector, 7 commodities in the Cereal sector and 4 commodities in the Animal sector. The analysis consists of three stages of waste appearance: production (harvesting, farming), processing and consumption (raw, uncooked food). Production data were taken from Eurostat, import and export data were taken from FAOSTAT. Methodology and calculations consist of relations between specific values. Those specific values for every commodity are the production data, import and export data, and consumption of raw food by the inhabitants of a country. Total consumption of raw food by inhabitant is calculated from the specific consumption per capita and population. The results of the study showed that from 2010 to 2016 in the EU28 the estimated quantity of the AWCB appeared to be around 18.4 billion tonnes, with the sector percentages as follows: Animal ~31%, Vegetable ~44%, Cereal ~22% and Fruit ~2%. In the Animal sector, the most dominant were developed countries, with high population density and high level of industrialisation. The Cereal, Fruit and Vegetable sectors have shown to generate higher AWCB quantities in the countries with more available land area and appropriate climate conditions.

Environmental regulations are gradually striving to decarbonize short-sea navigation fostering the replacement of the conventional power systems with alternative ones. The electrification of ships has been proposed in the literature as a pathway to zero-emission shipping. Among various alternatives, batteries could ensure full conformity with the tightening emission restrictions. However, appropriate batteries for short-sea navigation need to be investigated, since each battery technology has its own environmental impacts and characteristics such as energy density, number of battery cycles, cost, fast charging ability and safety. The aim of this research is to compare the conventional power system with a diesel engine and alternative power system with a selected battery to identify convenient technology for zero-emission shipping according to the environmental and economic criteria. The Life-Cycle Assessment (LCA) and the Life-Cycle Cost Assessment (LCCA) are performed to analyze environmental and economic performance of different powering options. The analysis included ro-ro passenger ships from the Croatian short-sea navigation, highlighting the electrification by a Lithium-ion battery as the most appropriate alternative according to environmental and economic indicators.

Biogas is an instrument of synergy between responsible waste management and renewable energy production in the overall transition to sustainability. The aim of this research is to assess the integration of the power-to-gas concept into a food waste-based biogas plant with the goal to produce renewable methane. A robust optimisation was studied, using linear programming with the objective of minimising total costs, while considering the market price of electricity. The mathematical model was tested at an existing biogas power plant with the installed capacity of 1 MWel. It was determined that the integration of power-to-gas in this biogas plant requires the installation of ca. 18 MWel of wind and 9 MWel of photovoltaics, while importing an additional ca. 16 GWhel from the grid to produce 36 GWh of renewable methane. The economic analysis showed that the feedstock gate fee contributes significantly to the economic viability of renewable methane: a change in the feedstock gate fee by 100 €/tonne results in a decrease of production costs by ca. 20–60%. The robust nature of the model showed that uncertainties related to electricity production from wind and photovoltaics at the location increased the cost of gas production by ca. 10–30%.

The aim of this study is to investigate the operation of biogas plants in advanced energy markets after energy crops become limited in their use and biogas plants exit subsidy schemes for electricity production. Continuous biogas combined heat and power production and sale of electricity on the day-ahead market could be a viable operation strategy only in the case of low-cost substrates. When the break-even cost of electricity production in biogas power plants reaches 100 €/MWhel, selling electricity on the day-ahead market does not create profit. The study shown that a more profitable operation strategy involves coupling biogas power plant operation on the electricity balancing market with biomethane production or combining a small-scale sugar beet processing facility with a biogas upgrading plant to cover heat demand for sugar beet processing. Techno-economic analysis showed that the viability of both alternative operation strategies is severely impacted by the selling price of biomethane. In the given market conditions, a selling price of biomethane below 50 €/MWh is not viable for a biogas plant. The model developed could be used as a guideline for biogas plant operators on how to proceed after significant changes appear in both biogas production and biogas utilisation.

Large amounts of food waste and sewage sludge exert a hazardous environmental impact in several countries. Producing biogas and digestate from food and industrial waste is one of the solutions for waste management, stabilization of sludge, resource and energy recovery and reductions in the amount of waste. However, biogas production from such substrates has challenges in degradation efficiency, inhibitory effects and other challenges, and thus co-digestion and pretreatment techniques could be applied to enhance biogas production. The aim of this study is to explore the effects of co-digestion of food waste, meat and bone meal and rendering wastewater sludge. First, thermal pretreatment was performed (35°C, 5 days) by adding the rendering-industry streams to food waste in the amounts of 0, 5, 10 and 15% on a total solid basis, and further anaerobic digestion (40.5°C, ca. 40 days) was then performed. Both experimental and kinetic analysis were conducted, and the major factors regarding opportunities and challenges in the two-stage process are discussed. Results have shown that both co-substrates from rendering industry decreased the biogas yield of food waste. When 5% of them was added to food waste, meat and bone meal decreased biogas production by 12%, and wastewater sludge decreased it by 23%. Both co-substrates, on the other side, increased the rate of reaction of food waste digestion when applying different common kinetic models.

Heat pumps are recognized as energy efficient and environmentally friendly technologies for cooling and heating. The objective of this paper is to identify the economic and environmental potential of seawater heat pump installed in a specialized hospital on the Mediterranean coast. A seawater heat pump is operating in the heating mode throughout the whole year and it is used for pool heating and domestic hot water production. Energy demand was studied for a whole year, and the economic benefits, as well as primary energy savings and CO 2 emissions reduction, were analysed. The analysis showed that the seawater heat pump would lead to 25% lower costs, 52% primary energy savings and 63% of CO 2 emission reduction in comparison to fuel oil boiler.

The aim of this research is to evaluate the thermogravimetric behaviour of roadside grass and its digestate obtained from mesophilic anaerobic mono-digestion by quantifying its impacts on biomass composition and properties. Thermogravimetric measurements were conducted in a laboratory furnace under nitrogen flowrate of 100 mL/min in the temperature range from 35 to 800 °C at five different heating rates of 2.5, 5, 10, 15 and 20 °C/min. Friedman and Kissinger- Akahira- Sunose differential and integral isoconversional models were applied to determine the distributions of activation energies and modified pre- exponential factors per reacted mass (degree of conversion). The investigation demonstrated that anaerobic digestion of roadside grass can be used to generate biochar- richer material (with significantly greater yield of final residues after pyrolysis) with less energy required for subsequent pyrolysis in comparison with raw roadside grass.

Sustainable management in the biogas production via anaerobic digestion process intents the use of alternative biomass sources that are not competitive with food production. The aim of this study is to investigate the application of the abundant-quantity residue in more sustainable production of heat and electricity along with the production of the digested substrate as a fertiliser. The study has been divided into several sequential steps. First, the grass samples have been collected at the following locations: uncultivated land, river embankment and highway verge. The greatest grass yield has been determined for the riverbank grass, with an average value of 19 t/ha of fresh mass and 2.6 t/ha of dry mass. Next, the chemical characterisation of the collected residue grass and the laboratory batch mono and co-digestion tests with maize silage and cattle slurry have been conducted. The results show that all grass samples have satisfying digestive parameters (C/N ratio between 16.6:1 to 22.8:1) with the low presence of impurities, which makes them suitable for biogas production. The following biochemical methane potential in mono-digestion of residue grass has been recorded: uncultivated land (0.275 Nm3/kgTS), riverbank (0.192 Nm3/kgTS) and highway verge (0.255 Nm3/kgTS). The control of the process has been improved in co-digestion tests, by avoiding acidification in the first days of the operation. The estimation of kinetic parameters in mathematical modelling has shown that the degradation of residue grass shows some different parameters compared to the previous study. The model results for the gas phase show some small deviations compared to the experimental data. Based on the life cycle analysis results it can be concluded that there are perspectives in the use of residual grass compared to maize silage in the production of heat and electricity, especially in the improvement of ecosystem quality.

This paper presents a new approach for modeling energy flows in complex energy systems with parallel supply of fresh water and electricity. Such systems consist of renewable energy sources (RES), desalination plant, conventional power plants and the residual brine storage which is used as energy storage. The presented method is treating energy vectors in the system as control variables to provide the optimal solution in terms of the lowest critical excess of electricity production (CEEP) and highest possible share of RES in the supply mix. The optimal solution for supplying the demands for fresh water and electricity is always found within the framework of model constraints which are derived from the physical limitations of the system. The presented method enables the optimization of energy flows for a larger period of time. This increases the role of energy storage when higher integration of RES in the supply mix. The method is tested on a hypothetical case of Jordan for different levels of installed wind and PV capacities, as well as different sizes of the brine storage. Results show that increasing the optimization horizon from one hour to 24 h can reduce the CEEP by 80% and allow the increase of RES in the supply mix by more than 5% without violating the CEEP threshold limit of 5%. The activity of the energy (brine) storage is crucial for achieving this goal.

District heating systems represents one of the ways by which the European Union is trying to reach set goals in energy efficiency and security field. These systems allow the use of different energy sources including local energy sources such as waste and biomass. This paper provides economic viability assessment of using these fuels in the district heating system. Economic evaluation is based on regression analysis from data of existing plants and on the locally dependent data. Some of parameters that are dependent of local parameters are price and available fuel quantity, therefore these values are separately modelled; biomass as a function of location of the plant while municipal waste as a function of location and the time changes in waste quantity and composition which depend of socio-economic trends and legislation. This methodology is applied on the case of district heating plants in the City of Zagreb where internal rates of return are calculated for four considered scenarios. Results indicate that waste powered plant can improve its profitability by co-combusting other local wastes while economic viability is achieved by introduction of region wide waste management system. Reducing plant capacity, based on prognosis of waste generation, showed that these plants can be competitive with biomass plants.

Jordan is a country faced with several environmental and energy related issues. It is the Worlds' fourth most water deprived country with a water consumption of only 145 m3 per capita annually, less than a third of the established severe water poverty line. Jordan is also a country rich in wind and solar potential but practically no utilization with 99% of the produced electricity coming from imported fossil fuels resulting in high CO2 emissions and a potential security of supply issue. The utilization of reverse osmosis desalination in a combination with brine operated pump storage units and wind and (PV) photovoltaic plants can tackle both issues. The desalination plants can produce the much needed water and act as a flexible demand to increase the penetration of intermittent renewables supported by the brine operated pump storage units. This paper presents six scenarios for the development of the Jordanian energy system until the year 2050. The results have shown that the demonstrated configuration can increase the share of intermittent renewables in the production of electricity up to 76% resulting in a high reduction of fuel consumption, CO2 emissions and costs. These analyses have been performed using the EnergyPLAN advanced energy system analyses tool.

This paper investigates the application of riverbank grass as a potential alternative energy crop for maize silage in the production of biogas. Grass samples have been mowed on the embankments of the Sava River in the city of Zagreb, Croatia. Carbon and nitrogen content and C/N ratio have been determined in the grass samples. Further, laboratory investigations on the anaerobic mono- and co-digestion of the collected riverbank grasses with different ratios with maize silage and animal manure have been conducted. The laboratory reactors have operated under the mesophilic conditions (39 °C) with the dry matter contents of 6 %. During the anaerobic digestion process, the biogas production and composition and pH value of the reaction mixture have been monitored. Results show that the riverbank grass could serve as a (co)-substrate in the anaerobic mono- and co-digestion.

This paper investigates current and planned investments in new power plants in Bosnia and Herzegovina and impact of these investments on the energy sector, CO2 emission and internationally committed targets for electricity from renewable sources up to year 2020. Bosnia and Herzegovina possesses strong renewable energy potential, in particular hydro and biomass. However, the majority of energy production is conducted in outdated power plants and based on fossil fuels, resulting in environment pollution. New major investments The Stanari Thermal plant (300 MW) and the investment in Block 7 (450 MW) at the Thermal Plant Tuzla are again focused on fossil fuels. The power sector is also highly dependent on the hydrology as 54% of current capacities are based on large hydro power. In order to investigate how the energy system of Bosnia and Herzegovina will be affected by these investments and hydrology, the EnergyPLAN model was used. Based on the foreseen demand for year 2020 several power plants construction and hydrology scenarios have been modelled to cover a range of possibilities that may occur. This includes export orientation of Stanari plant, impact of wet, dry and average year, delayed construction of Tuzla Block 7, constrained construction of hydro power plants, and retirement of thermal units. It can be concluded that energy system can be significantly affected by delayed investments but in order to comply with renewables targets Bosnia and Herzegovina will need to explore the power production from other renewable energy sources as well.

In this paper, the energy potential of biomass from growing short rotation coppice on unused agricultural land in the Republic of Croatia is used to investigate the feasibility of Combined Heat and Power (CHP) facilities fueled by such biomass. Large areas of agricultural land that remain unused for food crops, represent significant potential for growing biomass that could be used for energy. This biomass could be used to supply power plants of up to 15 MWe in accordance with heat demands of the chosen locations. The methodology for regional energy potential assessment was elaborated in previous work and is now used to investigate the conditions in which such energy facilities could be feasible. The overall potential of biomass from short rotation coppice cultivated on unused agricultural land in the scenarios with 30% of the area is up to 10 PJ/year. The added value of fruit trees pruning biomass represents an incentive for the development of fruit production on such agricultural land. Sensitivity analysis was conducted for several parameters: cost of biomass, investment costs in CHP systems and combined change in biomass and technology cost.

Even though the Republic of Croatia is on track of achieving goals set in the Europe 2020 strategy, to achieve the goals set in the 2030 European framework for climate and energy policies will require more effort. The new 2030 framework calls for a reduction in greenhouse gas emissions by at least 40% compared to the 1990 level, yet the Republic of Croatia does not have such an ambitious plan. In times when wind plants and photovoltaic systems have reached grid parity in the majority of European countries, this paper analysed the influence of construction of wind and photovoltaic power plants in order to present the optimal constructing ratio of such systems on the Croatian power system load. Simulations have been conducted in the EnergyPLAN model for the year 2012. After the simulation presented promising scenarios, applying the Pareto analysis showed the optimal scenario for generating electricity from renewables, scenario with the lowest import of electricity, scenario with the lowest CO2 emissions and with the lowest critical excess electricity production. In addition, all of the scenarios were subjected to a multiple criteria decision analysis in order to find the best overall scenario. After showing that the best overall scenario was 1.65 GW of wind power plants and 1.6 GW of installed PV capacity, a multi-criteria analysis was performed in order to observe the behaviour of grading the scenarios. Indeed, all of the simulations proved that PV will have a bigger role in the Republic of Croatia than expected.

South East Europe consists of several smaller countries in terms of energy systems and thus, integrating energy systems of the whole region has significant benefits for allthe countries included. However, as there are large differences between energy mixes of the countries included, careful energy planning needs to be carried out in order tosatisfy energy needs of all the countries of the region.Due to the significant differences in geography and the climate of different parts of the region, many different technologies need to be introduced in order to have optimal,low-carbon energy mix.In this paper, steps toward the 100% renewable energy system (RES) for the year 2050 have been presented. Novelty in this paper, compared to the similar research alreadybeing carried out, is the sustainable use of biomass in 100% RES, as this is the only way in which biomass can be considered as carbon-neutral. Smart energy systems’approach has been used in planning of 100% RES, which considers significant integration of the electrical, heating and gas sectors. Many technologies have been employedin the year 2050, but the major share is put on photovoltaics and wind energy, followed by geothermal, solar thermal, CHPs driven on biomass, hydro power and syntheticfuel technologies. Finally, it was shown that the 100% RES in the year 2050 is cheaper than the reference system, developed for the year 2012.

This paper provides methodology for regional analysis of biomass energy potential and for assessing the cost of the biomass at the power plant (PP) location considering transport distance, transport costs and size of the power plants. Also, methodology for determination of an upper-level price of the biomass which energy plant can pay to the external suppliers has been proposed. The methodology was applied on the case of Croatia and energy potential of biomass in the Croatian counties was calculated, using different methodologies, for wheat straw, corn stover and forestry residues, types of biomass considered economically viable at the moment. Results indicate that the average energy potential of wheat straw is 8.5 PJ, corn stover 7.2 PJ and forestry residues 5.9 PJ.

Several Contracting Parties to the Treaty establishing the Energy Community of the South East Europe, currently in energy transition, have electricity production dominantly based on lignite which contrasts their new reality. Planning approach to designing a new feasible energy policy is presented in this paper. This novel approach in using EnergyPLAN tool stems from analysis of market operation of lignite thermal power plants on hourly basis, and quantification of the feasibility of the energy policy and its alignment with EU vision, and is presented in few scenarios. It was found out that the Serbian energy system is highly sensitive to the electricity market and CO2 tax increase, because the marginal costs for lignite generation will increase to more than 50€/MWh. Shifting in the merit order will be observed even at lower CO2 tax levels, because of the intensity of the emission of the electricity sector (calculated to be higher than 700gCO2/kWhel, according to current energy policy). Based on the increased use of renewable energy sources and more efficient energy conversion technologies, socio-economic and energy policy feasibility would be increased, while long-term marginal costs would be improved by 2€/MWh and emission intensity by 258 gCO2/kWhel, compared to the current energy policy. These contributions, shown in the Serbian case, are of general importance for other lignite dominated Contracting Parties to Treaty establishing the Energy Community. [Projekat Ministartsva nauke Republike Srbije, br. 42009]

This paper provides a solution for managing excess heat production in trigeneration and thus, increases the power plant yearly efficiency. An optimization model for combining biomass trigeneration energy system and pit thermal energy storage has been developed. Furthermore, double piping district heating and cooling network in the residential area without industry consumers was assumed, thus allowing simultaneous flow of the heating and cooling energy. As a consequence, the model is easy to adopt in different regions. Degree-hour method was used for calculation of hourly heating and cooling energy demand. The system covers all the yearly heating and cooling energy needs, while it is assumed that all the electricity can be transferred to the grid due to its renewable origin. The system was modeled in Matlab© on hourly basis and hybrid optimization model was used to maximize the net present value (NPV), which was the objective function of the optimization. Economic figures become favorable if the economy-of-scale of both power plant and pit thermal energy storage can be utilized. The results show that the pit thermal energy storage was an excellent option for storing energy and shaving peaks in energy demand. Finally, possible switch from feed-in tariffs to feed-in premiums was assessed and possible subsidy savings have been calculated. The savings are potentially large and can be used for supporting other renewable energy projects.

Water resources are a crucial problem for a number of arid countries. One possible solution for this issue is the implementation of desalination but its utilization can greatly increase the demand for electricity. An important concept for a wide scale implementation of desalination is the integration of water and energy resources. Jordan is currently one of the most water deprived countries in the world. It is also a country very rich in renewable energy sources but almost no utilization of that potential. A combination of desalination, pump storage that utilize the produced brine and renewable energy sources could solve both issues. The desalination plants could produce enough water to ensure the supply for Jordan’s ever growing population while the use of wind and solar power could provide much needed electricity and reduce the need for imported fossil fuels as well as CO2 emissions. The goal of this paper is to evaluate the impact of desalination in a combination with pump storage that utilizes the produced brine on the penetration of intermittent renewable energy sources in an energy system. The analysis has been conducted on a case study for the country of Jordan using the EnergyPLAN advanced energy system analyses tool.

Croatian energy system is currently highly import-dependent and integration of a high share of renewable energy sources needs to be considered. This paper studies eight scenarios; three proposed by the Croatian Energy Strategy, one proposed by the Indicative medium-term development plan of Croatia’s Transmission System Operator, and four alternative scenarios that propose extensive construction of hydro, wind and solar power plants in Croatia. Calculations have been conducted in the EnergyPLAN model based on modeled long term energy demand projections in the NeD model, with 2009 as the base year and a scope ranging until the year 2030. Each of the eight proposed scenarios is observed through different hydrological conditions while analyzing import dependency, economic costs and CO2 emissions. After the initial calculations, additional analysis of intensive wind power penetration has been conducted. The Results show that energy systems with a larger share of conventional and nonflexible power plants have more difficulty adjusting to wind power plants production. In case of a high share penetration of wind in a system based upon such power plants, the feasibility of investing in new large combustion plants that will spend most of the time working on minimum capacity is brought into question.

Macedonian energy sector is the main emitter of greenhouse gases with share of about 70% in the total annual emissions. Also, 70%–75% of emissions are associated with the electricity generation due to the predominant role of the lignite fuelled power plants. Recently, the government has adopted a strategy for the use of renewable energy sources (RES) which identifies a target of 21% of final energy consumption from RES by 2020. In this paper, analyses are conducted in order to investigate to which extent and in which way the absorption capacity of the power system for RES electricity can be improved. For this purpose, combining various conventional and RES technologies, including pump storage hydro power plant and revitalisation of the existing lignite power plants six scenarios for the power system expansion are developed by making use of EnergyPLAN model. Critical excess of electricity analyses are conducted in order to identify the maximal penetration of wind electricity. The results have shown that in the exiting capacities maximal penetration of wind electricity in 2020 is 13% of total electricity consumption. The revitalization of the existing lignite power plants and building of pump storage power plant would increase the wind penetration. Furthermore, the developed scenarios are comparatively assessed in terms of the associated greenhouse gases emissions and import of electricity.

Serbia has wind with a good capacity factor, the respectable potential of which has not hitherto been utilized. There are a number of proposed wind power projects with an envisaged capacity of up to 2500 MW and the project documentation has been developed for 1300 MW. Within the existing feed-in tariff scheme, only 500 MW are eligible. This limitation is set in a conservative manner bearing in mind moderation (balancing) needs due to the variability of wind power generation. The existing Serbian energy system, with significant hydro generation, available pumped storage hydro capacity, and strong interconnections has many moderators for variable wind generation and for reliable technical performance of the grid. In this study, energy imbalances under different levels of wind penetration into the Serbian energy system were analyzed. Possible new moderation strategies for lowering energy imbalances due to wind integration were evaluated using the EnergyPLAN tool and are presented in this paper.

Island communities require in-detail mapping of resources available for exploitation for energy purposes, since infrastructure and connections to the mainland present, in most cases, a weak point of the island energy supply. As the present energy supply on Croatian islands relies mostly on fossil fuels and electricity from the mainland, it becomes obvious that exploitation of renewable energy sources is the only solution that leads towards self-sufficiency and sustainable development. In order to design a self-sufficient and sustainable island, three major technological changes are needed: integration of renewable energy sources alongside with energy savings and improvements in energy efficiency in the energy production. Analyses for several other Croatian islands have been performed using Renewislands/ADEG methodology in order to assess all possible outcomes. The scenarios in these cases have shown that islands can become self-sufficient through combining renewable technologies and energy storage systems. Energy storage systems will be crucial for achieving desired objectives in terms of energy independence from the mainland and in general import of fossil fuels. The analysis conducted for the island of Hvar will result in creation of several scenarios which will clearly point out the favorable solutions for improvement of both security of energy supply and covering the majority of energy demand with renewable energy sources and storage technologies. Also, when talking about implementation of renewable technologies on island of Hvar, an optimal mix of technologies must be applied in order to avoid excess costs and to achieve minimal impact on environment in terms of visual pollution.

The most important problems the energy sector faces in Macedonia are an unfavourable energy mix with a high prevalence of lignite, a strong dependence on energy import, poor condition of the energy system and inefficiency in energy production and use. This paper investigates the prospects for realization of the 100% renewable energy system in Macedonia by making use of the EnergyPLAN model. Analysis was conducted for two renewable scenarios designed for the years 2030 and 2050. First scenario, the 50% renewable energy system, has been created for the year 2030 and represents the first step towards the 100% renewable energy future of Macedonia. The second scenario has been designed for the 100% renewable energy system based only on the renewable energy sources in the year 2050. Special attention in the design of these systems has been given to intermittent renewable energy sources and to storage technologies. The analysis reveals that at the moment the 50% renewable energy system seems much more likely than the 100% renewable energy system, but with additional energy efficiency measures, which will lead to a decrease of consumption and with installation of new generation capacities this goal can be easily achieved.

A building, energy demand and heating. Transport, fuel mix and demand Energy supply of buildings, transport industry. Electric fuel mix 2050

The energy sector in Macedonia is the main emitter of greenhouses gases (GHG) with share of about 70% in the total annual emissions. Furthermore, within the energy sector, 70–75% of emissions are associated with the electricity generation due to the predominant role of the lignite fuelled power plants. This makes the electricity sector the most significant key source and, at the same time, the main target for CO2 emissions reduction. Recently, the government has adopted a strategy for the use of RES which identifies a target of 21% of final energy consumption from RES by 2020. The main goal of this paper is to investigate environmental and economic aspects of higher penetration of renewables into energy system of Macedonia. For this purpose a reference energy scenario for the power system expansion is developed by making use of EnergyPLAN model. The reference energy system was developed for the year 2020, and then used in the scenario analyses. The analyses of four ‘RES’ scenarios reveal that renewables can reduce CO2 emissions between 0.84% and 9.54% compared to reference scenario. Increase of CO2 price for double, compared to today’s price, will lead to increase of annual operating costs over 26% in all the scenarios considered. In the case of doubling the lignite price, annual operating costs in scenarios will be increased between 6.5% and 7.6%.

The share of energy from renewable energy sources (RES) in the final gross energy consumption in Macedonia is about 14%, mostly due to the electricity produced by large hydro power plants and the use of biomass for heating. Macedonian energy sector is the main emitter of greenhouses gases (GHG) with share of about 70 % in the total annual emissions. Also, 70-75 % of emissions are associated with the electricity generation due to the predominant role of the lignite fuelled power plants. Recently, the government has adopted a strategy for the use of RES which identifies a target of 21% of final energy consumption from RES by 2020. In this paper analyses are conducted in order to investigate to which extent and in which way the absorption capacity of the power system for RES electricity can be improved. For this purpose, combining various conventional and RES technologies, including pump storage hydro power plant and revitalisation of the existing lignite power plants six scenarios for the power system expansion are developed by making use of EnergyPLAN model. Critical excess of electricity (CEEP) analyses are conducted in order to identify the maximal penetration of wind electricity. The results have shown that in the exiting capacities maximal penetration of wind electricity in 2020 is 13 % of total electricity consumption. The revitalization of the existing lignite power plants and building of pump storage power plant would increase the wind penetration. Furthermore, the developed scenarios are comparatively assessed in terms of the associated greenhouse gases emissions and import of electricity.