Primary Energy Factor Research Articles

Standardizacija u oblasti zelene gradnje - zgrade gotovo nulte energije nZEB (Nearly Zero-Energy Buildings)

European legislation EPBD [1] (Energy Performance of Buildings Directive) makes nearly Zero-Energy Buildings (nZEBs) a standard by 2020. The technology is already available and proven; however, the large-scale uptake of nZEB construction and renovation will be a big challenge for all market actors and stakeholders involved. A substantial gap in reliable data on current market activities makes it difficult for policy-makers to evaluate the success of their policies and measures [2]. As concrete numeric thresholds or ranges are not defined in the EPBD, these requirements let a lot of space for own interpretation and thus allow Member States (MSs) to define their nZEB in a very flexible way taking into account their country specific climate conditions, primary energy factors, ambition levels, calculation methodologies and building traditions. This is also the main reason why existing nZEB definitions differ significantly from country to country. It is thus a challenging task to find a common denominator for defining an nZEB on a European scale [1,2].

Achieving near Zero Energy Building in Albania: An Approach for the Retrofit of a Public-School Building

Since its introduction in 2010, the nearly Zero Energy Building (nZEB) concept has known a large diffusion in European countries. Albania, an aspiring candidate country to join the European Union EU, is paving the way towards its introduction by transposing EU directives in the fields of energy efficiency into the national legislation. Most of the national building stock includes buildings with low thermal and energy performance but with high refurbishment potential, too. The country can become an important contributor in the EU decarbonization strategy due to the high percentage of electricity produced by hydropower stations, making it one of the least carbon-intensity countries in the electricity production point of view. The article focuses on the evaluation of the energy performance of an existing school located in Tirana and the potentialities to reach the nZEB target, analysing both the suitable technological solutions and the energy market situation. The Primary Energy Factors PEF for the local electricity market are estimated referring to statistical data and in comparison, with neighbouring countries, Italy and Greece, in order to investigate the potential of the achievement of the nZEB target in Albania.

Influence of Thermal Retrofitting on Annual Energy Demand for Heating in Multi-Family Buildings

The paper presented the analysis of heat consumption for heating in multi-family residential buildings before and after thermal retrofitting. The analysis involved four groups of buildings, i.e., 43 buildings in total, located in various localities, belonging to one weather station. The predicted level of energy savings resulting from thermal retrofitting was achieved from the energy audits. The actual heat consumption, following the calculation into so-called external standard conditions, was obtained based on the readouts from heat-meters. For each building, the values of heat consumption over the periods of 6–10 years were read. The performance measurements involved the periods before, during, and after thermal retrofitting. The following statistical tests were used for data analysis: Wilcoxon–Mann–Whitney, Shapiro–Wilk, Bartlett, ANOVA, Kruskal–Wallis, Dunn and Holm post-hoc. The performed analyses showed that the mean value of energy savings predicted by audits reached 38.5% when the real mean value of savings, achieved from heat-meters, equaled 30.3%. The annual energy demand factors for heating were calculated for final energy and non-renewable primary energy factors. It was established that most of the analyzed objects fulfilled the primary energy factor requirements found in the Polish technical and construction regulations, which were valid at the time of investment.

Perspectives for Mitigation of CO2 Emission due to Development of Electromobility in Several Countries

The creep trend method is used for the analysis of the development of electric car production in three regions: The United States, the European Union and Japan. Based on vehicle registration and population growth data for each year the creep trend method using historical data for the years 2007–2017 is applied for forecasting development up to 2030. Moreover, the original method for calculating the primary energy factor (PEF) was applied to the analysis of power engineering systems in the regions investigated. The assessment of the effects of electromobility development on air quality has been performed, reduction values for pollutant and greenhouse gas emissions have been determined, which was the main objective of this manuscript. Mitigation of air pollutant emissions, i.e., carbon dioxide (CO2), carbon monoxide (CO) and nitrogen oxides (NOx) was estimated and compared to the eventual expected increase of emissions from power plants due to an increase of the demand for electricity. It can be concluded that electricity powered cars along with appropriate choices of energetic resources as well as electricity distribution management will play the important role to achieve the sustainable energy economy. Based on the emission reduction projections resulting from the projected increase in the number of electric cars, (corrected) emissions will be avoided in 2030 in the amount of over 14,908,000 thousand tonnes CO2 in European Union, 3,786,000 thousand tonnes CO2 in United States and 111,683 thousand tonnes CO2 in Japan.

Analysis of Primary Energy Factors from Photovoltaic Systems for a Nearly Zero Energy Building (NZEB): A Case Study in Lithuania

Following a new climate and energy plan, the European Union (EU) gives big attention to energy savings. The overall assessment of energy saving measures is very important. Thus, it is crucial to estimate in a proper way the primary energy factor, which is used in calculations of primary energy consumption from renewable energy (RE) sources in a Nearly Zero Energy Building (NZEB). The conduced studies of the literature and national regulations showed that different methods to determine energy from photovoltaic (PV) systems are used. The aim of this paper is to evaluate the primary energy factors of energy from photovoltaics and determine the average value. To achieve this aim, the data of 30 photovoltaic systems from Lithuania were analyzed. The results show a 35% diversification in the values of non-renewable primary energy factor, depending on the PV systems’ capacities, with the average on a level of 1.038.

Energy, Environmental and Economic Analysis of Air-to-Air Heat Pumps as an Alternative to Heating Electrification in Europe

Heat pumps (HP) are an efficient alternative to non-electric heating systems (NEHS), being a cost-effective mean to support European building sector decarbonization. The paper studies HP and NEHS performance in residential buildings, under different climate conditions and energy tariffs, in six different European countries. Furthermore, a primary energy and environmental analysis is performed to evaluate if the use of HPs is more convenient than NEHS, based on different factors of the electric mix in each country. A specific HP model is developed considering the main physical phenomena occurring along its cycle. Open data from building, climatic and economic sources are used to feed the analysis. Ad hoc primary energy factors and greenhouse gas (GHG) emission coefficients are calculated for the selected countries. The costs and the environmental impact for both heating systems are then compared. The outcomes of the study suggest that, in highly fossil fuels dependent electricity mixes, the use of NEHS represents a more efficient decarbonization approach than HP, in spite of its higher efficiency. Additionally, the actual high price of the electric kWh hampers the use of HP in certain cases.

High-Temperature Geothermal Utilization in the Context of European Energy Policy—Implications and Limitations

The European Union (EU) has made climate change mitigation a high priority though a policy framework called “Clean Energy for all Europeans “. The concept of primary energy for energy resources plays a critical role in how different energy technologies appear in the context of this policy. This study shows how the calculation methodologies of primary energy content and primary energy factors pose a possible negative implication on the future development of geothermal energy when comparing against EU’s key energy policy targets for 2030. Following the current definitions of primary energy, geothermal utilization becomes the most inefficient resource in terms of primary energy use, thus contradicting key targets of increased energy efficiency in buildings and in the overall energy use of member states. We use a case study of Hellisheidi, an existing geothermal power plant in Iceland, to demonstrate how the standard primary energy factor for geothermal in EU energy policy is highly overestimated for efficient geothermal power plants. Moreover, we combine life cycle assessment and the commonly utilized combined heat and power production allocation methods to extract the non-renewable primary energy factor for geothermal and show how it is only a minimal fraction of the total primary energy factor for geothermal. The findings of the study apply to other geothermal plants within the coverage of the European Union’s energy policy, whether from high- or low-temperature geothermal resources. Geothermal has substantial potential to aid in achieving the key energy and climate targets. Still, with the current definition of the primary energy of geothermal resources, it may not reach the potential.

Assessments of effects of implementation of strategic plans for development of Belgrade District heating system

The district heating system (DHS) is one of the key elements of the Belgrade energy system. Overview of the current state and basic characteristics of the DHS are presented in this paper. The focus is on the planned development of DHS and on the analyses of effects of realization of measures and projects defined by strategic documents related to DHS which are adopted by city authorities (Development Strategy of DHS and Strategy of Belgrade Development). Two exploratory scenarios were developed by using the LEAP tool. Heat consumption, fuel mix, and CO2 emission are presented for both scenarios. Different measures on the demand side and infrastructural development in these two scenarios are analyzed using indicators related to the security of supply (primary energy factor, import dependency) and to climate change (CO2 emissions). The results show that the aim of current strategic documents was to provide security of supply (mostly by the introduction of heat from the thermal powerplant and to less extent by the introduction of RES and improvement of efficiency), while the climate issues were mostly neglected. The positive effect of the introduction of RES to CO2 emission was nullified by the indirect introduction of lignite in the energy mix.

Analysis of the Impact of the Fireplace Heating on the Energy Performance of the Family House

Reduction of energy use in buildings is an important measure to achieve climate changes of mitigation. It is essential to minimize heat losses when designing energy efficient buildings. For energy efficient building in a cold climate, a large part of the space heating demand is caused by transmission losses through the building envelope. In compliance with the today's trend of designing sustainable and energy-saving architecture, it is necessary firstly to solve the factors influencing the energy balance. This year the subsidy for houses has been valued at € 8,000. The condition is that the building is classified in the energy class A0 according to the Energy Performance Act. Energy class A0 characterizes nearly zero energy buildings. The main concern is for the public to become interested in such buildings. The subsidy is designed to reward and promote those buildings that their heat and technical characteristics and modern technical equipment that meet energy class. In addition to a good plan to raise the profile of such buildings, there has been a lot of speculation to help make buildings in energy class A0. They are mainly owners of family houses where there is no gasification and are forced to have electricity as a source of heat and hot water. Electricity has a high primary energy factor, which means that buildings do not have to be approved.

Self-learning model predictive control for dynamic activation of structural thermal mass in residential buildings

Changes in the electricity supply system induce the challenge of matching the highly fluctuating and unpredictable renewable energy generation with the yet inflexible electricity demand. This leads to an increasing demand for energy storage and demand-flexibility. Electrification of residential heating systems in combination with advanced controls utilizing dynamically the structural thermal mass (STM) of buildings as thermal storage could provide some of the required demand flexibility.In this work, a model predictive control (MPC) algorithm is developed and applied within a simulation framework to control dynamic heating operation as a measure of STM based residential load shifting (LS). The self-learning algorithm is functional without extensive measurement data or expert knowledge for parametrization. It optimizes heating operations required for LS according to a dynamic primary energy factor signal, while observing transient thermal comfort constraints. The implemented auto-regressive black-box model with explanatory variables predicts thermal conditions within the observed thermal zone with sufficient quality to support MPC. Based on that model, the control algorithm successfully activates STM as a measure of LS according to the given primary energy (PE) oriented utility function. For the observed system, the PE demand can be reduced by 3–7% while maintaining or even improving the thermal comfort.

Heat dispatch centre – Symbiosis of heat generation units to reach cost efficient low emission heat supply

The application of renewable heat supply technologies underlies various constraints. To overcome these limitations to their application in this research, an interconnection of different heat sources in the so-called Heat-Dispatch-Centre is derived from the main characteristics of renewable heat supply technologies. A season-dependent operation state of generation and storage units allows low-emission and efficient heat supply. In addition, alternative connection possibilities are discussed and a visualization method for an analysis of heat generation units connected in series is introduced. For an exemplary network an overall primary energy factor of 0.09 and a specific CO2 emission factor of 27 gCO2/kWh is reached, with costs of overall heat generation at 11–12 €ct/kWh. In contrast to this, a parallel connection of the heat sources reduces overall efficiency, increases the costs to 13 €ct/kWh and increases the CO2-emissions in the overall energy supply system by decreasing renewable electricity infeed into the grid.

Cost-efficient Nearly Zero-Energy Buildings (NZEBs)

The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and even higher energy performance levels throughout many EU countries. However, most of the high performance buildings realised so far result in additional investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU Horizon 2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The project focus is on multi-family houses. In each of the four participant countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of market-ready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies. Since details of the CoNZEBs work are presented in several additional papers, this document gives an overview of the different tasks and results that are available so far.

The Development of Electromobility in Poland and EU States as a Tool for Management of CO2 Emissions

The article analyzes the dynamics of the development of the electromobility sector in Poland in the context of the European Union and due to the economic situation and development of the electromobility sector in the contexts of Switzerland and Norway. On the basis of obtained data, a forecast was made which foresees the most likely outlook of the electric car market in the coming years. The forecast was made using the creeping trend method, and extended up to 2030. As part of the analysis of the effect of the impact of electromobility, an original method was proposed for calculating the primary energy factor (PEF) primary energy ratio in the European Union and in its individual countries, which illustrates the conversion efficiency of primary energy into electricity and the overall efficiency of the power system. The original method was also verified, referring to the methods proposed by the Fraunhofer-Institut. On the basis of all previous actions and analyses, an assessment was made of the impact of the development of the electromobility sector on air quality in the countries studied. Carbon dioxide tank-to-wheels emission reductions which result from the conversion of the car fleet from conventional vehicles to electric motors were then calculated. In addition to reducing carbon dioxide emissions, other pollutant emissions were also calculated, such as carbon monoxide (CO), nitrogen oxides (NOx) and particulate matter (PM). The increase in the demand for electricity resulting from the needs of electric vehicles was also estimated. On this basis, and also on the basis of previously calculated primary energy coefficients, the emission reduction values have been adjusted for additional emissions resulting from the generation of electricity in power plants.

THE EFFECT OF EXOGENOUS FACTORS ON THERMAL POWER PLANT EFFICIENCY

This study focuses on the relationship between exogenous factors (that cannot be directly impacted by the actions of an economic agent) and combined heat and power (CHP) plant efficiency. As a measure of fuel utilization efficiency this paper proposes to use the Сoefficient of Fuel Utilization (CFU), which is the Russian equivalent of the Primary Energy Factor indicator. Climate conditions and fuel type were used as the exogenous factors in this article. Climate conditions were measured via climate zone proxies. The cause-effect relationships were analyzed using a linear regression model. The findings of the study showcase that the plants, which use natural gas as their primary fuel, show higher fuel utilization efficiency compared to coil plants. Climate conditions were also proven to be a statistically significant factor with plants situated in the third climate zone (mostly regions of the Central and North-Western federal districts) showing the highest average CFU of about 71%. The research shows that the exogenous factors account for close to 20% of CHP plant fuel utilization efficiency in Russia. The authors conclude that climate conditions and fuel type should be taken into account when constructing various energy efficiency models applicable to the Russian context.

Investigation and Evaluation of Primary Energy from Wind Turbines for a Nearly Zero Energy Building (nZEB)

In order to fulfill the European Energy Performance of Buildings Directive (EPBD) requirements regarding the reduction of energy consumption in buildings, great attention is paid to primary energy consumption. Wind energy is considered a type of primary energy. The analysis of the literature has revealed that wind energy is evaluated by different methods. Therefore, the aim of this article is to calculate the effect of the parameters of wind sources and wind speed on the primary energy factor of wind turbines. In order to achieve this aim, the primary energy factor of investigated 100 wind turbines and 11 wind farms operating in Lithuania was calculated. The results of the investigation show that the difference in the non-renewable primary energy factors between wind turbines with regard to their capacity is 35%. In addition, primary energy factor (PEF) values depend on geographic location and climate conditions. This paper provides a recommendation that the EU energy efficiency and renewable energy directives and regulations of all EU member states should use the same or, at least, a very similar methodology for the calculation of the primary energy factors of renewable and non-renewable energy sources.

Energy and Cost Analysis of Adapting an Existing Building to 2017 Technical Requirements and Requirements for NZEB

Energy efficiency is a very important factor in the Building sector. Building sector consumes about 40% of the world total energy. At present, new buildings in Poland and other European countries are designed according to very strict requirements. The problem arises when we take into consideration large number of the existing buildings. These buildings, especially the ones built in the last century, consume a lot of heating energy. Thermal protection requirements for the existing buildings subjected to thermo-modernization are specified in the technical regulations. Thermal protection requirements for thermo-modernized buildings in different countries are different. In Poland, a thermos-modernized building must meet the requirements for thermal protection of external partitions. In Ukraine, the requirements of thermal protection are modelled on European regulations. In Ukraine’s, thermos-modernized buildings must meet the requirements for thermal protection of external partitions and primary energy requirements. However, in Poland thermo-modernized buildings do not have to meet the requirement for a non-renewable primary energy factor – EP. [kWh/(m2y]. The existing buildings do not always have the option of converting a non-renewable heat source into renewable heat sources. In the article, the authors presented the energy analysis of adapting an existing building to the current technical requirements in Poland (WT 2017) and to the level of requirements for buildings of “almost zero energy consumption NZEB” (WT 2021) and adapting an existing building to the current technical requirements in Ukraine. The analysis was carried out based on thermo-modernization audits carried out for a single-family residential building. The analysed building was built in 80’s in traditional technology. It is a two-story building located in Krakow. The audits considered various options for improving energy efficiency. Financial outlays for each variant will be determined. The authors of the article pointed out that comfort in buildings subjected to thermo-modernization a very important issue. On the example of an existing residential building, the authors analysed how to improve the vibration comfort of use in the rooms of a building.

Renewable Energy Generation Scenarios Using 3D Urban Modeling Tools—Methodology for Heat Pump and Co-Generation Systems with Case Study Application †

In the paper, a method was developed to automatically dimensionalize and calculate central energy generation and supply scenarios with a district heating system for cities based on 3D building models in the CityGML format and their simulated heat demand. In addition, the roof geometry of every individual building is used to model photovoltaic energy generation potential. Two types of supply systems, namely a central heat pump (HP) system and a large co-generation (combined heat and power-CHP) system (both with a central storage and district distribution system), are modeled to supply the heat demand of the area under investigation. Both energy generation models are applied to a case study town of 1610 buildings. For the HP scenario, it can be shown that the case study town’s heat demand can be covered by a monovalent, low-temperature system with storage, but that the PV only contributes 15% to the HP electricity requirement. For the CHP scenario, only 61% of the heat demand can be covered by the CHP, as it was designed for a minimum of 4000 operating hours. Both the PV and the CHP excess electricity are fully injected into the grid. As a result, the primary energy comparison of both systems strongly depends on the chosen primary energy factors (PEF): with given German regulations the CHP system performs better than the HP system, as the grid-injected electricity has a PEF of 2.8. In the future, with increasingly lower PEFs for electricity, the situation reverses, and HPs perform better, especially if the CHP continues to use natural gas. Even when renewable gas from a power to gas (P2G) process is used for the CHP, the primary energy balance of the HP system is better, because of high conversion losses in the P2G process.

Impact analysis of energy efficiency measures in the electrolysis process in primary aluminium production

The Paris Agreement includes the goals of ‘holding the increase in the global average temperature to well below 2°C above pre-industrial levels’ and ‘making finance flows consistent with a pathway towards low greenhouse gas emissions’. Industrial energy efficiency will play an important role in meeting those goals as well as becoming a competitive advantage due to reduced costs for companies. The aluminium industry is energy intensive and uses fossil fuels both for energy purposes and as reaction material. Additionally, the aluminium industry uses significant amounts of electricity. The electrolysis process in the primary production of aluminium is the most energy- and carbon-intensive process within the aluminium industry. The aim of this paper is to study the effects on primary energy use, greenhouse gas emissions and costs when three energy efficiency measures are implemented in the electrolysis process. The effects on the primary energy use, greenhouse gas emissions and costs are calculated by multiplying the savings in final energy use by a primary energy factor, emissions factor and price of electricity, respectively. The results showed significant savings in primary energy demand, greenhouse gas emissions and cost from the implementation of the three measures. These results only indicate the size of the potential savings and a site-specific investigation needs to be conducted for each plant. This paper is a part of a research project conducted in close cooperation with the Swedish aluminium industry.

Cost-efficient Nearly Zero-Energy Buildings

The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and also even higher energy performance levels throughout all EU countries. However, most of the high performance buildings realised so far result in higher investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU H2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The focus is on multi-family houses. In each of the four participating countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of marketready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies.

Energy and emission impacts of liquid fueled engines compared to electric motors for small size motorcycles based on the Brazilian scenario

Real data from dynamometric essays of electric and internal combustion engines motorcycles pointed out a 3 times superior energy performance of electric driven vehicles (47.06% efficiency) compared to the average value for liquid fueled engines (15.32%). That conclusion motivated a more comprehensive assessment, based on a bottom-up methodology together with the Primary Energy Factor PEF, in order to enlarge the energy chain by considering the Brazilian energetic matrix. Environmental impact is considered through the evaluation of greenhouse gases. PEF is calculated for five motorcycles based on 2010 to 2016 production data, followed by a projection for the years 2021, 2025 and 2026. PEF average values for electric and liquid fueled motorcycles are 3.5 and 7.1 respectively. The experimental tank-to-wheel efficiency ratio of 3 to 1 from dynamometric essays turns to be a well-to-wheel 2 to 1 ratio whenever the enlarged energy chain is considered. PEF method applied to dynamometric results shows that electric driven motorcycles are still more energy efficient than liquid fueled similar vehicles for the Brazilian matrix. Emissions from electric conversion are still less harmful, nevertheless battery impact must be better studied.