Energy Efficiency Scenarios Research Articles

Life Cycle Assessment with BIM Towards Sustainable Energy Policy-Making: The Case of Urban Transformation in Istanbul

Buildings are responsible for almost forty percent of global energy. Due to their high consumption of energy, buildings are on the front line of sustainability researches. In Turkey, six million out of twenty-two million buildings need to be demolished and rebuilt to meet seismic standards. These buildings are also far below the standards in terms of energy efficiency. Therefore, urban transformation can be thought of as a great opportunity for energy efficiency. This study investigates four things: (i) the energy-efficient urban transformation strategy in Gaziosmanpaşa-Istanbul region, which is selected as a case study; (ii) the effect of energy efficiency in this market; (iii) the adequacy of energy standards of Turkey; and (iv) contribution of digitalization in construction to sustainability with Building Information Modelling (BIM) and energy analysis. According to the energy efficiency scenarios, energy analyses were carried out on the BIM model. The most cost-effective strategy was determined with the Life Cycle Cost method. When compared with the current situation, it is possible to save energy up to 227 GWh a year, which is equal to the annual heating energy demand of approximately 30,000 housing, in the case study area with the most efficient scenario to be realized.

Impacts of reducing air pollutants and CO2 emissions in urban road transport through 2035 in Chongqing, China

The road transport sector in megacities is confronted with pressing local air pollution and carbon dioxide (CO2) control issues. To determine effective policy instruments for saving energy and the co-control of air pollutants and CO2, several mainstream measures were examined and compared in Chongqing's road transport sector from 2017 to 2035. An integration assessment framework was developed by combining the Long-range Energy Alternatives Planning (LEAP) system and a set of quantitative methods for evaluating the co-benefits of emission reductions (including the air pollutant equivalent (APeq), co-control coordinate system, and pollutant reduction cross-elasticity (Elsa/b)). Results showed that the shifting transportation modes scenario presented the most significant potential for energy-saving and emission reductions, reducing energy use by 30.9% and air pollutants and CO2 emissions by approximately 27–32% compared with the business as usual (BAU) scenario in 2035. The improving energy efficiency scenario also provided significant co-benefits for reducing air pollutants and CO2 emissions. Nevertheless, the promoting alternative fuel scenario may increase fine particulate matter (PM2.5) emissions by 2.2% compared to BAU in 2035 under the cleanness of regional electricity in 2017. Our findings suggest that the shifting transportation modes were effective measures to reduce air pollutants and CO2 in the short term synergistically, and highlighted the importance of cleaner electricity generation to develop electric vehicles in the medium and long term.

Typical Daily Profiles, a novel approach for photovoltaics performance assessment: Case study on large-scale systems in Chile

A growing photovoltaic industry shows exponential deployment worldwide, and it is expected to largely contribute to the energy transition. Because PV technologies will play a major role in achieving global sustainable development and climate goals, driving more energy-efficient scenarios will require efficient approaches to evaluate systems, especially when dealing with big data of a large region or portfolio. In this work, a novel approach for the PV performance assessment of photovoltaic systems, called “Typical Daily Profiles” (TDP), is presented. This approach is tested on the entire PV fleet operating in Chile from 2014 to 2019. The TDP approach can help to calculate key performance indicators, identify the mounting configuration of PV systems, and to detect major technical issues. A detailed validation carried on the Chilean PV fleet confirms the TDP approach's capabilities to provide accurate PV performance results, neglecting external factors such as failures, grid curtailment, or poor operation activities. Chile was chosen due to the large variety of climate zones in its unique geography, which helps to understand the PV performance under different environmental conditions. Besides, this study reveals the immense potential of PV technologies in Chile compared to mature PV markets worldwide. On an annual basis, their unit capacity factors can reach up to 38%, performance ratios above 90%, and the highest energy yield close to 3350 kWh/kWp. Proving to be an accurate tool, the Typical Daily Profiles approach can be easily applied to other PV portfolios in different regions, and a periodical execution could help to identify and understand long-term performance losses.

Infrared Signatures in The Modern Warship

A key aspect in design of the modern warship from the point of view of energy efficiency is undoubtedly the selection of its propulsion system. A large part of the total Infrared (IR) radiation emitted by the ship will be originated from propulsion, because not all the energy generated will be transformed into effective work. The remaining energy will contribute directly to the IR signature of the warship as a whole, thus increasing its susceptibility and, therefore, its casualty. The aim of this article is to describe the main sources of IR signature on frigates and destroyers, current and future IR signature reduction countermeasures, and present the results of an Infrared Control Measures (IRCM) study in which the vessel's ability to dissuade aerial threats through the use of deception techniques, within a stated energy efficiency scenario, is analysed. In conclusion, electrical variants to warship propulsion systems are more efficient under the same operating conditions, and their associated reduction of waste energy contribute favourably to IR signature control. The activation of IRCM will further reduce the IR susceptibility of a warship.

Long-term evolution of energy and electricity demand forecasting: The case of Ethiopia

Long-term energy demand forecasting is crucial for any country, in particular for developing countries with rapid developments of energy needs. This study focuses on Ethiopia, a country with a highly increasing energy demand resulting mainly from the currently low share of electricity access, rapid development of industrial parks, extensive expansion of the railway network, extensive irrigation schemes for agriculture, new cement and sugar factories, housing projects, power export plan to neighboring countries, etc. These all are on top of the 2.7% average population growth. In this study, the Long-range Energy Alternatives Planning System (LEAP) is used to explore different possible futures and also to forecast the long-term energy requirements in Ethiopia. The planning period is 33 years from 2018 to 2050. The study employs six different scenarios to unfold the future evolution. The developed scenarios are Business-As-Usual (BAU), Growth in Electrification and Urbanization (E&U), High Economic Growth (HEG) and three policy-driven, Improved Energy Efficiency (IEE-1, IEE-2 and IEE-3) scenarios. The pathways represented by these scenarios can show the maximum expected rise in demand under different drivers and the best-case energy saving opportunities. The model is also used to estimate the associated greenhouse gas (GHG) emissions.

A systems engineering framework for the optimization of food supply chains under circular economy considerations

The current linear “take-make-waste-extractive” model leads to the depletion of natural resources and environmental degradation. Circular Economy (CE) aims to address these impacts by building supply chains that are restorative, regenerative, and environmentally benign. This can be achieved through the re-utilization of products and materials, the extensive usage of renewable energy sources, and ultimately by closing any open material loops. Such a transition towards environmental, economic and social advancements requires analytical tools for quantitative evaluation of the alternative pathways. Here, we present a novel CE system engineering framework and decision-making tool for the modeling and optimization of food supply chains. First, the alternative pathways for the production of the desired product and the valorization of wastes and by-products are identified. Then, a Resource-Task-Network representation that captures all these pathways is utilized, based on which a mixed-integer linear programming model is developed. This approach allows the holistic modeling and optimization of the entire food supply chain, taking into account any of its special characteristics, potential constraints as well as different objectives. Considering that typically CE introduces multiple, often conflicting objectives, we deploy here a multi-objective optimization strategy for trade-off analysis. A representative case study for the supply chain of coffee is discussed, illustrating the steps and the applicability of the framework. Single and multi-objective optimization formulations under five different coffee-product demand scenarios are presented. The production of instant coffee as the only final product is shown to be the least energy and environmental efficient scenario. On the contrary, the production solely of whole beans sets a hypothetical upper bound on the optimal energy and environmental utilization. In both problems presented, the amount of energy generated is significant due to the utilization of waste generated for the production of excess energy.

GIS-based urban energy modelling and energy efficiency scenarios using the energy performance certificate database

The EU building stock is 97% not energy efficient and the promotion of energy retrofitting strategies is a key way of reducing energy consumptions and greenhouse gas emission. In order to improve the energy performance of buildings, the European Union released the Energy Performance of Buildings and the Energy Efficiency Directives. The certification of the energy performance of a building is a central element of these Directives to monitor and promote energy performance improvements in buildings, with the aim of increasing their energy efficiency level, thereby reducing greenhouse gas emissions. This work evaluates the energy performance of existing residential buildings using the energy performance certificate database and identifies the more effective retrofitting interventions by applying an urban-scale energy model. The novelty of this study is that a new retrofitting database is created to improve the results of a building energy model at urban scale taking into account the real characteristics of the built environment. The here presented GIS-based monthly engineering model is flexible and easily applicable to different contexts, and was used to investigate energy efficiency scenarios by evaluating their effects of city scale. An urban energy atlas was designed for an Italian city, Turin, as a decision-making platform for policy makers and citizens. This energy platform can give information on energy consumption, production and productivity potential, but also on energy retrofitting scenarios. The results of this work show that it is possible to obtain energy savings for space heating of 79,064 MWh/year for the residential buildings connected to the district heating network in the city of Turin; these interventions refer mainly to thermal insulation of buildings envelope with windows replacement and allow a reduction in greenhouse gas emissions of 12,097 tonCO2eq/year.

The effects of shading devices on office building energy performance in Mediterranean climate regions

Fixed shading devices (SDs) are still used as an essential and useful element in architectural design. Even with minor changes to be made when designing these devices, the energy performance of a building, especially in hot climate regions, can be significantly increased. In contrast to studies using one or a few parameters, this study aimed to make a comprehensive evaluation by considering more parameters simultaneously to determine energy-efficient fixed external SD scenarios that can be used in office buildings. This approach increases the accuracy of the results in terms of providing trade-offs. This study also aims to fill the gap of the research on SD strategies in Turkey. A total of 1485 scenarios were created with fixed external SDs (overhangs, horizontal and vertical louvers, and egg-crate variations) using the parameters of direction, glazing type, window-to-wall ratio (WWR), SD depth, and slope. Primary energy consumption values of all scenarios were calculated with the DesignBuilder software. Results were discussed according to the impact of each parameter on energy consumption and evaluated through descriptive statistical analysis. As a result, energy-efficient scenarios were determined. The best scenarios obtained for each SD type reduced the cooling energy consumption by between 37% and 49% compared to the no shading scenario using high-performance glazing type and by between 73% and 78% compared to the no shading scenario using low-performance glazing type. The total annual energy consumption was reduced by approximately 33% and 70%, respectively.

A novel spatial based approach for estimation of space heating demand saving potential and CO2 emissions reduction in urban areas

Space heating accounts for the most significant share of final energy demand in buildings in colder climatic regions contributing to greenhouse gas emission. In addition, there is a lack of data available to assess spatially, the potential of space heating demand reduction in different buildings when considering typical building refurbishment measures. Hence, in this paper, a robust information socket for urban building stock is developed to assess the impact of energy efficiency measures on space heating demand savings and CO2 emission reduction potential in the existing buildings based on a Geographical Information System tool. The model considers the topology and thermal performance of different building categories; houses with and without thermal insulation, apartments, commercial, public, office, and industrial buildings. Three scenarios, a reference and two additional scenarios using Prishtina city as a case study, have been created for standard (scenario 1), and advanced energy efficiency (scenario 2) measures based on the government’s proposed policies. The findings show that space heat demand saving potential for scenario 1 and 2 in comparison to the reference scenario was 50% and 68.5% respectively. Moreover, the CO2 emissions are reduced significantly from 502.3 mil kgCO2/year in reference scenario to 249.8 mil kgCO2/year for scenario 1 and 158.7 mil kgCO2/year in scenario 2 respectively.

Energy efficiency in leading emerging and developed countries

This paper defines the diverging interests of multiple actors in typically achieving and advancing energy efficiency. Gaps in the literature include the short elaboration of energy efficiency factors and conditions and the lack of information about developed and developing countries and thorough consideration of their specific features, impeding the development and implementation of detailed energy efficiency management strategies. It is against this backdrop that this paper seeks to identify the essence of energy efficiency and developing specific recommendations for achieving the most beneficial effect and well-balanced energy efficiency on the global scale, within the achievements of international goals in sustainable development. The paper exposes the critical factors of energy efficiency, accurately models the best energy efficiency characteristics, and settles the best energy consumption structure. The methodological purpose is to find different energy efficiency scenarios and disentangle fundamental differences in energy efficiency in developed and developing countries. The paper indicates that the reasonable likelihood of noteworthy achievement results in energy efficiency with insignificant mid-term changes. We give recommendations about well-balanced energy efficiency on the global scale and global progress in sustainable development.

Enabling NOMA in Overlay Spectrum Sharing in Hybrid Satellite-Terrestrial Systems

In this paper, a hybrid satellite-terrestrial spectrum sharing system allows terrestrial secondary network to cooperate with a primary satellite network and to further provide higher spectrum efficiency. For massive connections design, we implement non-orthogonal multiple access (NOMA) technique to form cognitive radio based satellite-terrestrial (CR-NSHT) system relying on NOMA and further achieve more benefits compared with traditional schemes. The secondary network only remains its stable operation when the outage probability of such system is guaranteed, and thereby, to explore advantages of spectrum sharing opportunities. Considering Shadowed-Rician fading for satellite links, and Nakagami- $m$ as well as Rician fading for terrestrial links, we derive the closed-form expressions of the outage probability to evaluate the performance of secondary network. We consider further system performance metrics including ergodic capacity, energy efficiency and multi-user scenarios. We also demonstrate the impacts of power allocation factors, transmit signal-to-noise ratio (SNR) at the source, parameters of satellite links, target rates, and fading severity parameters on the system performance. Numerical and simulation results validate our analysis and highlight the performance gains of the proposed schemes for CR-NSHT with relay link serving secondary network and direct link serving the primary network.

Energy Consumption and Transportation in Developing Countries: Need for Local Scenario-Based Energy Efficiency Plans

Energy Consumption and Transportation in Developing Countries: Need for Local Scenario-Based Energy Efficiency Plans

Defining Criteria for the Selection of Measures to Increase Energy Efficiency in Public Buildings

Buildings, although one of the largest energy consumers in the world, also represent big potential to reduce energy consumption, dependence on fossil fuels and carbon dioxide emissions, through the implementation of energy efficiency measures. Improvement of energy efficiency of existing buildings requires a dedicated, serious and detailed approach. Investors are often guided by economic criteria, which greatly influence on investments and interventions, potentially causing some negative side effects (comfort reduction, use of energy-intensive materials, etc.). Therefore, it is very important to rely on methods that provide detailed and affordable cost, technical and environmental analysis. Energy efficiency methods are often based on simple methods such as research, estimation of energy consumption, preliminary design, estimation of energy savings and financial cost-effectiveness. For example, in energy audits of buildings, annual energy consumption and cost-effectiveness are considered for analysis. For a more detailed assessment, a calculation tool based on the calculation of energy consumption of particular facility and the estimation of energy savings after the proposed energy efficiency measures is being used. The proposed measures generally represent a classic scenario of energy efficiency measures. In this paper, factors such as comparison of the share of fossil fuels and renewable energy sources (RES), the estimation of cost-effectiveness of the use of renewable energy technologies, aspect of embodied energy in materials and life cycle assessment in buildings are being considered. This paper defines the criteria for the evaluation of scenarios (functional groups of measures) for increasing energy efficiency of the building, which include, in addition to energy and economic aspects, environmental aspect. The six criteria have been defined for evaluation of energy efficiency scenarios related to: annual energy consumption, total annual primary energy, share of RES in primary energy, direct and indirect carbon emissions, embodied energy in applied materials and investment per scenario. For each criteria an expression for its calculation is given. Defined criteria are calculated for six scenarios of increasing the energy efficiency of Mechanical Engineering Faculty, University of Sarajevo. Based on the calculated different values of criteria of considered aspects, it is possible to identify in more detail way critical points, advantages and disadvantages of different combinations of energy efficiency measures, which can further serve to identify the best strategy necessary for evaluation of energy performance of the building before and after the intervention.

Contribution of the Basilicata region to decarbonisation of the energy system: results of a scenario analysis

This paper investigates the energy system of the Basilicata region (southern Italy) to highlight, through a scenario analysis, its possible future development in compliance with the European Commission's long-term vision. The IEA-ETSAP methodology was utilized to model and analyse the Basilicata energy system in a business-as-usual scenario, based on the assumptions of the 2010 Regional Energy and Environmental Policy Plan, and in two low-carbon scenarios, decarbonisation and high energy efficiency, which, in line with the long-term European strategy, foresee an 85% carbon dioxide emission reduction and a 20% energy efficiency increase in 2050. The results highlight that electricity production from renewable energy sources (in particular wind energy), strongly supported by the regional policy, goes beyond the Basilicata Regional Energy-Environmental Plan forecast, with a further increase in the decarbonisation scenarios. In addition, solar thermal and highly efficient technologies are adopted in commercial and residential end-use sectors. An additional 9% reduction in energy consumption is achieved in the high energy efficiency scenario by passive houses. The proposed approach shows the usefulness of a modelling framework typically used for national and supranational analyses to support regional authorities in their decision-making process to obtain results in line with the European and national strategies. Application to the Basilicata region shows the usefulness of a consolidated framework for policy assessment at a local scale to assess regional contribution to the achievement of national climate mitigation targets that tend towards climate neutrality.

Comparing energy and material efficiency rebound effects: an exploration of scenarios in the GEM-E3 macroeconomic model

This paper uses the GEM-E3 macroeconomic computable general equilibrium model to calculate the magnitude of greenhouse gas (GhG) emission rebound effects across a range of efficiency scenarios in the automotive sector supply chain. The scenarios are technically feasible as they are designed using bottom up information from the iron and steel industry. Rebound effects occur when efficiency improvements reduce prices, stimulating demand and offsetting some of the environmental benefits that would otherwise be had. This paper allows energy, material and product-service efficiency rebound effects to be compared for the first time. The results suggest that there is a greater risk of rebound effects for downstream emissions abatement strategies that save embodied emissions: 85% of the emissions savings in the product-service efficiency scenario and 77% of emissions in the material efficiency scenario are offset by economy-wide rebound effects. This compares to 7% in the energy efficiency scenario. These findings show that, in the current policy environment in which GhG emissions remain relative unconstrained, improvements in material efficiency that are particularly good at spurring growth are also likely to carry the greatest rebound effects. The conclusions of this paper are not purely dependent on the chosen macroeconomic model, but are a function of the underlying value structure along supply chains: downstream efficiency improvements that save embodied emissions involve greater potential monetary savings per unit GhG avoided, spurring rebound effects.

Service Embedding in IoT Networks

The Internet of Things (IoT) is the cornerstone of smart applications such as smart buildings, smart factories, home automation, and healthcare automation. These smart applications express their demands in terms of high-level requests. Application requests in service-oriented IoT architectures are translated into a business process (BP) workflow. In this paper, we model such a BP as a virtual network containing a set of virtual nodes and links connected in a specific topology. These virtual nodes represent the requested processing and locations where sensing and/or actuation are needed. The virtual links capture the requested communication requirements between nodes. We introduce a framework, optimized using mixed integer linear programming (MILP), that embeds the BPs from the virtual layer into a lower-level implementation at the IoT physical layer. We formulate the problem of finding the optimal set of IoT nodes and links to embed BPs into the IoT layer considering three objective functions: i) minimizing network and processing power consumption only, ii) minimizing mean traffic latency only, iii) minimizing a weighted combination of power consumption and traffic latency to study the trade-off between minimizing the power consumption and minimizing the traffic latency. We have established, as reference, a scenario where service embedding is performed to meet all the demands with no consideration to power consumption or latency. Compared to this reference scenario, our results indicate that the power savings achieved by our energy efficient embedding scenario is 42% compared with the energy-latency unaware service embedding (ELUSE) reference scenario, while our low latency embedding reduced the traffic latency by an average of 47% compared to the ELUSE scenario. Our combined energy efficient low latency service embedding approach achieved high optimality by jointly realizing 91% of the power and latency reductions obtained under the single objective of minimizing power consumption or latency.

Life cycle cost optimization of building façade: A social housing case

In this paper, a common social housing archetype design was studied in order to improve the energy and cost performance. The focus is on evaluating the effects of some parameters of the design of the façade in particular: the size of the windows and the optical and thermo-physical properties of the components. The aim is to obtain cost optimal energy efficient scenarios in accordance with the Recast of Energy Performance of Buildings Directive (EPBD Recast) by determining efficient thicknesses of the insulation for the exterior walls and efficient window sizes and types of glazing for each orientation, simultaneously. The parameters of the façade are optimized in order to obtain the dominant values and ranges in terms of energy and cost. There are remarkable differences in the dominant options for the thickness of the insulations, as well as the type and size of windows: they depend on whether they have a north, south and east–west orientation. The decision makers should design each façade in dependence on its orientation to determine its optimal optical and thermo-physical properties in terms of its cost and its consumption of energy. A reduction by approximately 5% in the life cycle cost and 17% in the primary energy use was achieved through the optimization of the base case.

Future energy pathways for a university campus considering possibilities for energy efficiency improvements

The study aimed to show in a systematic way possible energy efficiency measures that would decrease the total energy use at the university campus in Trondheim, Norway. The entire study was developed in close collaboration with the NTNU Property and Technical Management divisions, meaning that suggested energy efficiency scenarios and other assumptions were highly relevant. Currently, the campus floor area is about 300 000 m2 and consists of buildings combining offices, lecturing halls, study halls, and laboratories. The campus building stock has been built from 1910 to 2002. To perform this study, building performance simulation and the dynamic segmented modeling were combined. A dynamic neighborhood building stock model was utilized to aggregate the outputs from the building simulation and evaluate global effects of energy efficiency measures. Reference building models for each university cohort were developed based on the methodology for defining the reference buildings. The results of the single reference building analyses showed that a decrease of up to 50% in heating energy use might be achieved by increasing efficiency of the ventilation system and by decreasing the temperature of the heating system. The results showed that in spite of building stock growth, the estimated energy use would decrease from 2017 to 2050 by 10% for the standard renovation, and by 26% for the combination of ambitious renovation and technical improvements.

Edge Computing, IoT and Social Computing in Smart Energy Scenarios.

The Internet of Things (IoT) has become one of the most widely research paradigms, having received much attention from the research community in the last few years. IoT is the paradigm that creates an internet-connected world, where all the everyday objects capture data from our environment and adapt it to our needs. However, the implementation of IoT is a challenging task and all the implementation scenarios require the use of different technologies and the emergence of new ones, such as Edge Computing (EC). EC allows for more secure and efficient data processing in real time, achieving better performance and results. Energy efficiency is one of the most interesting IoT scenarios. In this scenario sensors, actuators and smart devices interact to generate a large volume of data associated with energy consumption. This work proposes the use of an Edge-IoT platform and a Social Computing framework to build a system aimed to smart energy efficiency in a public building scenario. The system has been evaluated in a public building and the results make evident the notable benefits that come from applying Edge Computing to both energy efficiency scenarios and the framework itself. Those benefits included reduced data transfer from the IoT-Edge to the Cloud and reduced Cloud, computing and network resource costs.

The Multiple Benefits of the 2030 EU Energy Efficiency Potential

The implementation of energy efficiency improvement actions not only yields energy and greenhouse gas emission savings, but also leads to other multiple impacts such as air pollution reductions and subsequent health and eco-system effects, resource impacts, economic effects on labour markets, aggregate demand and energy prices or on energy security. While many of these impacts have been studied in previous research, this work quantifies them in one consistent framework based on a common underlying bottom-up funded energy efficiency scenario across the EU. These scenario data are used to quantify multiple impacts by energy efficiency improvement action and for all EU28 member states using existing approaches and partially further developing methodologies. Where possible, impacts are integrated into cost-benefit analyses. We find that with a conservative estimate, multiple impacts sum up to a size of at least 50% of energy cost savings, with substantial impacts coming from e.g., air pollution, energy poverty reduction and economic impacts.