District energy management systems (DEMS) offer the capability to harness the energy potential of districts. Currently, there is a lack of research describing the necessary underlying information ...systems. An overview of lessons learned is presented from a series of workshops with experts from industry, research, and further roles, predominately from Germany. Seven workshops discussing challenges within digitalization, data requirements, district energy system planning, common elements in district energy systems are conducted, ensuring long‐term operation and transferability, and validation of prior findings. Based on these discussions, insights into topics such as the key data and its requirements, typical distinctions in DEMS, their infrastructure, considerations in the information modeling, as well as challenges in data availability, are offered. These findings are mapped to a data value pipeline, illustrating key resources and tools needed to plan and operate DEMS. As demonstrated in this article, the requirements for DEMS highlight their complexity. Distinct categorizations, such as the ownership or heterogeneity in building and technologies, form the landscape of DEMS. The need for standardized, interoperable systems is often a contrast to the uniqueness of individual systems and their needs. Further adoption of the described concepts necessitates sustainable business models.
The authors host workshops on district energy management systems with experts from Germany, where they explore a range of questions and share their findings. The main topic is the planning, operation, and evaluation of said systems. They map key tools and methodologies onto a data value pipeline, categorize different types of districts, and propose concepts for further research.
Due to the potential for deploying distributed generation, improving energy efficiency and adopting sustainable energy-related practices, consumers provide significant value in the energy sector ...transformation. If their interests and goals are similar, they can group together and form energy communities. Energy communities enable consumers to jointly pursue their individual and collective economic, environmental and social goals, while simultaneously contributing to the decarbonisation of the energy system. Considering the growing interest in this field, this paper aims to enhance the understanding of the social arrangements, the technical designs and the impacts of energy communities. The social arrangements of energy communities are discussed in relation to the different actors, their roles and interactions. Then, the paper reviews the technical aspects of designing various local energy systems, while taking into account the goals of energy community members and outside actors. The reviewed literature is benchmarked with respect to the methods, modelling objectives and the constraints used in the design process. Finally, the paper quantifies the economic, environmental, technical and social impacts of energy communities, reviews the numerical indicators used to quantify these impacts and provides a critical discussion of the findings. Based on the findings, future research directions are highlighted.
•The social arrangements, roles and interactions in energy communities are reviewed.•Literature on optimal design is benchmarked in terms of objective and modelling.•Economic, environmental, technical and social impacts are reviewed.
In the framework of distributed energy planning, evaluating reliable energy profiles of different sectors has a prominent role. At the same time, it is a quite challenging task, since the ...availability of actual energy profiles of buildings at the district level is not widespread. A survey of over 70 studies in scientific literature has been accomplished and a set of criteria has been defined for classifying the selected contributions based on the energy demand data features, source and/or estimation methods, highlighting the ones adopting hourly energy profiles. As final results, tables summarizing the main methods characteristics and a selection of studies providing directly useable energy profiles are reported. Therefore, this study could be useful for stakeholders involved in energy simulations of buildings stocks and community energy planning in assessing the buildings energy demand, with different desired level of detail and available data. The research, broadly, demonstrates that the potential replicability of analysed methods is constrained to the datasets availability and, particularly, highlights the need of reliable hourly energy profiles definition for developing accurate energy scenarios.
•A review of over 70 studies focussing on urban buildings energy demand is presented.•A set of criteria for classifying the selected studies is defined.•The selected studies are classified by estimation method and time resolution.•Tables on methods' features and on studies with useable energy profiles are provided.•The review can support stakeholders involved in assessing buildings energy demand.
Renewable energy planning, electrochemical battery storages and advanced energy management strategies are flexible solutions for transformation towards smart grids, whereas the complex battery ...cycling ageing is nonlinearly dependent on intermittent renewable supply, stochastic load profiles and dynamic charging/discharging behaviors. In this study, a nonlinear mathematical model is developed to explore effective strategies for smart grids. A general regression learner-based battery cycling ageing prediction method is proposed for quantifications of lifetime battery cycling ageing and battery replacement times, including the database preparation, surrogate model training with typical feature extraction and classification, cross-validation, and performance prediction in various battery groups. A machine learning (ML) algorithm selection approach is proposed through the statistical analysis, to guide the accurate surrogate model development, considering the diversity in dynamic charging/discharging behaviours and intrinsic cycling ageing performances of each battery. Afterwards, a novel battery discharging control strategy is proposed, to address the contradiction between the economic cost-saving and the associated battery replacement cost. Last but not the least, the machine learning-based models are thereafter integrated in the district energy community for technical performance analysis. This study can provide a regression learner-based battery cycling ageing modelling method, a machine learning algorithm selection approach, and a holistic framework for systematic integration with avoidance on techno-economic performance overestimation, which is critical to guide renewable energy planning, electrochemical battery storages, and advanced energy management strategies.
•A regression learner-based model for dynamic battery ageing prediction.•Statistical analysis for selection of machine learning algorithm.•A novel battery control strategy to compromise operating and degradation cost.•An interactive energy sharing community with renewable and electric vehicle groups.•Techno-economic analysis on a district energy community with battery storage.
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•Energy efficiency, flexibility, robustness and resilience in multi-energy systems.•Sustainability and decarbonization transition with power supply reliability.•Typology ...transformation from centralized to distributed energy prosumers.•Cross-district spatiotemporal energy sharing for energy resilience and efficiency.•Preparation, survivability and restoration for energy resilience enhancement.•Frontier guidelines for planning, design and operation on district energy systems.
Energy efficiency, flexibility, and robustness can promote system sustainability and decarbonization under low-impact and high-probability events, whereas energy resilience is significant to survive power systems when suffering from high-impact and low-probability events. However, energy resilience is at its pregnancy stage with inconsistency in multiple perspectives, ranging from concept definition to quantification approach. Moreover, the consideration of energy resilience will conflict with energy efficiency, calling for the necessity on trade-off solutions. In this study, in order to ensure the survivability of district power systems when suffering from extreme events, an up-to-date review on concept definition and quantification approach of energy resilience was conducted, together with distinguished boundary and correlation with reliability, robustness, and flexibility in multi-energy systems. Recent advancement in distributed renewable systems, electric vehicles, peer-to-peer energy sharing, electrification and hydrogenation in power systems was provided, together with their potential contributions in future smart energy systems. By enabling each agent to become a power supply agent, a typology transformation from centralized to distributed energy prosumers was proposed, with an intermediate step-by-step transition from centralized power plants to distributed energy prosumers. Afterwards, multi-scale applications and future prospects of energy resilience are provided, including resilient heating/cooling of buildings, dynamical downscaling for robust design on urban morphology, mobility-based interactive energy sharing in regional districts, and smart microgrids with V2X (vehicle-to-everything) and energy flexible buildings. This study can highlight the significance in district energy resilience with joint and continuous endeavors and tradeoff solutions, during energy planning, design and operation stages.
•Two seasonal-regulatable solar energy utilization systems have been proposed.•Comprehensive performance is greatly enhanced via multi-objective optimization.•Solar year-round effective utilization ...period can be enhanced by 2.63-fold.•The investment is dramatically reduced by over 70% under the same conditions.
Space heating via fossil energy accounts for tremendous energy consumption and carbon emissions. Solar energy has enormous potential for building space heating in the heating season, but the more abundant solar resource is often in excess during the non-heating season, which leads to vast seasonal residual solar energy being wasted. In this paper, two solar seasonal-regulatable energy systems are proposed to solve this problem, i.e., System A: solar thermal and photovoltaic integration, and System B: solar thermal incorporating the organic Rankine cycle. Both systems are aimed at regulating the year-round solar energy for space heating in the heating season and making full use of solar seasonal residual energy for electricity generation in the non-heating season. The results show that the two systems can improve the effective solar utilization efficiency by 69.12% and 18.65%, respectively, and both can enhance the solar effective utilization period by 2.63-fold over the conventional solar thermal system. Besides, in comparison to the actual solar seasonal storage system monitoring data, both systems will dramatically decrease the investment cost by 72.69% and 72.22%, respectively. Overall, the superiority of solar seasonal-regulatable energy management systems in district-level applications is proven and it is instrumental in achieving the decarbonization goal.
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•A comparative assessment of district energy modelling tools was carried out.•Different levels of data detail and features for reliable results were explored.•A lack of robustness for ...result validation at the district level was identified.•29 energy modelling tools were evaluated with a focus on result validation.•The capabilities of such tools were stressed based on different criteria.
In order to reach the goal of reducing emissions by at least 55% by 2030 and achieving decarbonization by 2050, the increasing emphasis on net-zero energy buildings/districts encourages the development of advanced modelling tools to better design and manage district energy systems. This paper presents a critical review of such tools, considering the different detail level of building data and analysing the reliability of obtainable results. Initially, it elaborates on the characteristics of data resources and formats, energy demand representations of individual buildings, and the interconnection between individual buildings and districts, which are subsequently used to analyse the accuracy level of case studies. Then, the most used evaluation criteria for comparing tools are revised. Five categories are defined: (i) input data and representation of buildings, (ii) district energy system components (i.e., generation, distribution, storage), (iii) outdoor environment, (iv) user behaviour and mobility, and (v) validation and licencing. 29 tools suitable for district energy systems modelling are critically analysed with a focus on accuracy and validation, as well as on their application and future perspectives. The results highlighted the importance of data reliability in modelling approaches and results. Difficulties in achieving accurate results included robust data acquisition, interconnection among individual buildings, outdoor environment, and modelling approaches. The results also emphasized that, although no tools can cover all the possible features at the current stage, this study can support the selection of the most suitable tool for specific applications at the district scale.
Electrification and hydrogenation in buildings and transportations are estimated to reduce around 30% carbon emission in 2060, whereas the current literature provides few state-of-the-art reviews on ...advanced materials and approaches on electrochemical battery and hydrogen (H2) for the transition towards carbon-neutral districts. In this study, a systematic and comprehensive review on the transition towards carbon-neutral districts was conducted with energy storage techniques, spatiotemporal energy sharing, electrification and hydrogenation. Cutting-edge technologies on electrochemical battery and hydrogen storage are reported, in terms of advanced materials, prioritized storage approaches, and bottleneck technical challenges. Principal roles and underlying mechanisms on electrochemical battery and hydrogen storages were demonstrated, together with application prospects, such as decentralised and centralized battery sharing strategies, and the transfer from building-integrated micro-H2 systems to H2 stations. Afterwards, feasibility and possibility of mobility integration in a district energy community have been demonstrated, in terms of current status and public infrastructures (like electric vehicle and hydrogen refueling station), opportunities for electrification and hydrogenation in transportations, economic analysis on interactive energy sharing frameworks, and synergistic function with mutual benefits. In order to improve the efficiency of H2 systems with idling constraints, social acceptance among building owners on high-pressure H2 storage, and to provide frontier guidelines on mobility integration in within-city and inter-city energy systems, novel energy frameworks have been proposed, for district energy sharing and inter-city energy migration. Research results can provide optimal planning on national energy strategies, flexible integration, technical guidelines and economic incentives, to make preparations for the carbon neutrality transition.
•Electrification and hydrogenation in buildings and transportations.•Advanced materials and approaches for battery and hydrogen storages.•Roles and mechanisms of battery and hydrogen storages in a district community.•Interactive energy sharing with renewable power and hydrogen.•Frontier guidelines and economic incentives for carbon neutrality transition.
•Discuss data centers from perspective of energy prosumers in district energy system.•Review renewable energy usage in data centers and the related advanced controls.•Review data center’s waste heat ...recovery and reuse for district heating.•Review existing green data centers and related economic/environmental analysis.•Identify future research directions for improving data center’s overall performance.
As large energy prosumers in district energy systems, on the one hand, data centers consume a large amount of electricity to ensure the Information Technologies (IT) facilities, ancillary power supply and cooling systems work properly; on the other hand, data centers produce a large quantity of waste heat due to the high heat dissipation rates of the IT facilities. To date, a systematic review of data centers from the perspective of energy prosumers, which considers both integration of the upstream green energy supply and downstream waste heat reuse, is still lacking. As a result, the potentials for improving data centers’ performances are limited due to a lack of global optimization of the upstream renewable energy integration and downstream waste heat utilization. This study is intended to fill in this gap and provides such a review. In this regard, the advancements in different cooling techniques, integration of renewable energy and advanced controls, waste heat utilization and connections for district heating, real projects, performance metrics and economic, energy and environmental analyses are reviewed. Based on the enormous amount of research on data centers in district energy systems, it has been found that: (1) global controls, which can manage the upstream renewable production, data centers’ operation and waste heat generation and downstream waste heat utilization are still lacking; (2) regional climate studies represent an effective way to find the optimal integration of renewable energy and waste heat recovery technologies for improving the data centers’ energy efficiency; (3) the development of global energy metrics will help to appropriately quantify the data center performances.
The present study explores the implementation of district heating and cooling systems across a broad set of case studies reported in the literature. Topics addressed include their history, system ...identification, energy sources, design considerations, environmental impact, economic feasibility, performance analysis and the role of energy policy. The history of district heating and cooling systems reveals how available technology has influenced the configuration of district energy systems as more efficient and cleaner methods of providing heating and cooling have arisen. This leads to system identification based on primary energy sources, including the deployment of more and more renewable energy streams. Advantages and disadvantages of each energy source are examined in detail. Policies created by government and international entities will have a major impact on the future of research and development in district energy systems. Incentives may become necessary for creating favorable conditions for the efficient construction and utilization of district heating and cooling. Outcomes of these policies influence design considerations underlying any district energy system and their contribution in sustainability. Studies on greenhouse gas emissions along with the economic impacts of district energy construction are part of the design process and optimization of district energy systems should include economic and environmental considerations and not solely thermal efficiency. District heating and cooling systems are often integrated with components such as absorption chillers, cogeneration and thermal energy storage. Performance analysis using exergy and energy analysis have revealed several sources of irreversibility in district heating systems with these elements. If understood properly, these can greatly enhance system operation. Awareness and accommodation of the many factors discussed in this paper can improve the soundness of any district heating or cooling installation.
