Urban Smart Energy Systems from a Climate Change Perspective: Technical, Economic and Environmental Optimization Analysis

Energetic Communities: Planning support for sustainable energy transition in small- and medium-sized communities

Kleine und mittelgroße Kommunen könnten sich als die Schlüsselakteure erweisen, da viele Probleme innerhalb ihrer Zuständigkeitsbereiche gelöst werden müssen. Die Stadtentwicklung beschäftigt sich mit einer Vielzahl von städtischen Veränderungsprozessen. Energie ist hierbei ein verhältnismäßig neuer Aufgabenbereich und vielen Entscheidungsträgern fehlen die Erfahrung und solide Kriterien für die strategische Entscheidungsfindung. Nach einer Phase großer Entschlossenheit, den Klimawandel zu stoppen, scheint sich inzwischen eine gewisse Resignation bei Politikern, Planern und der Öffentlichkeit breit zu machen, da manches nicht wie gewünscht umgesetzt werden konnte und die Hoffnung auf schnelle Lösungen zunehmend schwindet. 'Rebound-Effekte' scheinen einen großen Teil der Einsparungen aufzuzehren und alternative Ideen zur Umsetzung nachhaltiger Energiesysteme haben in vielen Fällen nicht überzeugt. Energiesysteme erweisen sich als komplex. Nach wie vor wird die Energiewende als wichtiges Thema gesehen, wobei sich um die richtigen Umsetzungsschritte ein wachsender Dissens zeigt. Diese Arbeit beschäftigt sich mit der Frage, was Entscheidungsträger in kleinen und mittelgroßen Kommunen benötigen, um einen erfolgreichen Energiewendeprozess zu initiieren und umzusetzen. Auf Basis dieser sehr allgemeinen Fragestellung wurden vier primäre Forschungsfragestellungen formuliert: • Wie können Kommunen langfristige Energiewendevisionen in ihren strategischen Entwicklungsplänen verankern? • Welche Werkzeuge und Modelle sind für die Analyse kommunaler Energiesysteme einsetzbar? • Wie können Werkzeuge und Modelle auf die spezifischen Anforderungen und Randbedingungen der Testkommunen angepasst werden, um eine langfristige Umsetzung geeigneter Maßnahmen und Technologien zu erreichen? • Wie funktioniert der Einsatz der adaptierten Werkzeuge in der Testkommune und welche Hemmnisse müssen für den langfristigen Erfolg noch überwunden werden? Um diese Fragen zu beantworten, wurde eine Kombination aus wissenschaftlicher Literaturrecherche, praktischer Anwendung und Auswertung des Modells in der Testkommune gewählt.

Prospects for key technologies of new-type urban integrated energy system

Co-optimization of urban morphology and distributed energy systems is key to curb energy consumption and optimally exploit renewable energy in cities. Currently available optimization techniques focus on either buildings or energy systems, mostly neglecting the impact of their interactions, which limits the renewable energy integration and robustness of the energy infrastructure; particularly in extreme weather conditions. To move beyond the current state-of-the-art, this study proposes a novel methodology to optimize urban energy systems as interconnected urban infrastructures affected by urban morphology. A set of urban morphologies representing twenty distinct neighborhoods is generated based on fifteen influencing parameters. The energy performance of each urban morphology is assessed and optimized for typical and extreme warm and cold weather datasets in three time periods from 2010 to 2039, 2040 to 2069, and 2070 to 2099 for Athens, Greece. Pareto optimization is conducted to generate an optimal energy system and urban morphology. The results show that a thus optimized urban morphology can reduce the levelized cost for energy infrastructure by up to 30%. The study reveals further that the current building form and urban density of the modelled neighborhoods will lead to an increase in the energy demand by 10% and 27% respectively. Furthermore, extreme climate conditions will increase energy demand by 20%, which will lead to an increment in the levelized cost of energy infrastructure by 40%. Finally, it is shown that co-optimization of both urban morphology and energy system will guarantee climate resilience of urban energy systems with a minimum investment.

Recently it has become important to establish the local environmental preservation level based on the Agenda 21 including the local energy system In this study we examined the improvement techniques on an urban energy system in snowy cold region. We surveyed the possibility of new urban energy system like waste heat from incineration plants and sewage plants. We analyzed the results using fuzzy utility function and structural modeling. We simulated several scenarios on the urban new energy system which can be introduced and evaluated by using cost-performance with environmental cost. We proposed the rational energy system in a residential area in Sapporo practically.

Guest Editorial: Special issue on flexible and resilient urban energy systems

It is important to deal with energy saving in buildings of one city level, and plan the energy system from one building to one city level. We strongly suggest conducting urban building energy planning (UBEP) in the urban planning field in China. There are two main characteristics of an urban building energy system. First, the terminal building energy demand is dynamically timely. Second, the energy demand, energy sources supply, energy equipments, and networks of heating, cooling, gas, and electricity, are distributed in an urban space. It is meaningful to conduct an innovative urban energy planning with space distribution and time dynamic simulation. Therefore, an UBEP simulation tool, developed by our research group, is introduced. Finally, a case of energy planning in Beijing City in 2010 for heating and air conditioning system is dynamically simulated and analyzed. To meet the same building energy demand in Beijing, such as heating, air conditioning, gas, and electricity, different energy equipments, such as boiler, combined heating and power, combined cooling, heating, and power system, and heat pump based on different energy sources, such as coal, gas, and electricity, should be planned alternatively. Also, an optimum urban energy system with high energy efficiency and low environmental emission can be achieved. This simulation tool contains most models of heating and cooling energy systems in China. We can validate the models with statistical data from previous or present simulation, and the simulation results in future planning can serve as guidance for the construction of municipal energy infrastructure. We can conclude that simulation in time dimension shows the characteristics of dynamic load in each nodes of the energy flow. The objective is to present the comparison of different scenarios and optimize the planning schemes.

An IGDT-based a low-carbon dispatch strategy of urban integrated energy system considering intermittent features of renewable energy

The emergence of renewable-energy-source (RES) envelope solutions, building retrofit requirements and advanced energy technologies brought about challenges to the existing paradigm of urban energy systems. It is envisioned that the building cluster approach—that can maximize the synergies of RES harvesting, building performance, and distributed energy management—will deliver the breakthrough to these challenges. Thus, this paper aims to critically review urban energy systems at the cluster level that incorporate building integrated RES solutions. We begin with defining cluster approach and the associated boundaries. Several factors influencing energy planning at cluster scale are identified, while the most important ones are discussed in detail. The closely reviewed factors include RES envelope solutions, solar energy potential, density of buildings, energy demand, integrated cluster-scale energy systems and energy hub. The examined categories of RES envelope solutions are (i) the solar power, (ii) the solar thermal and (iii) the energy-efficient ones, out of which solar energy is the most prevalent RES. As a result, methods assessing the solar energy potentials of building envelopes are reviewed in detail. Building density and the associated energy use are also identified as key factors since they affect the type and the energy harvesting potentials of RES envelopes. Modelling techniques for building energy demand at cluster level and their coupling with complex integrated energy systems or an energy hub are reviewed in a comprehensive way. In addition, the paper discusses control and operational methods as well as related optimization algorithms for the energy hub concept. Based on the findings of the review, we put forward a matrix of recommendations for cluster-level energy system simulations aiming to maximize the direct and indirect benefits of RES envelope solutions. By reviewing key factors and modelling approaches for characterizing RES-envelope-solutions-based urban energy systems at cluster level, this paper hopes to foster the transition towards more sustainable urban energy systems.

ABSTRACTAs urban areas expand, energy demands are escalating, necessitating the development of urban energy systems (UES) to achieve energy conservation and emission reduction goals. Although small‐scale regional integrated energy supply technologies have reached a level of maturity, urban‐scale integrated energy supply solutions are still in development. In response, this study introduces an architecture for the UES and an economic and low‐carbon operation strategy. The approach begins by constructing a highly reliable and robust integrated energy system (IES) within each independent region to accommodate a variety of energy needs, followed by the establishment of an operational architecture for large‐scale urban energy systems. The study then examines the energy flow and the mathematical model of multiple energies within urban energy systems, simplifying the complex model for practical application. Subsequently, a multiobjective optimization model is developed to facilitate the large‐scale consumption of clean energy, with considerations for economic and low‐carbon operations, and is formatted into a linear programming model. The model's accuracy is empirically tested through numerical simulation in a city divided into three regions. The simulation results demonstrate substantial improvements in clean energy consumption, a reduction in carbon emissions, and a decrease in operational costs. Specifically, the proposed strategy can boost the clean energy consumption rate to 96.41%, cut operational costs by up to 50.13%, and lower carbon dioxide emissions by up to 57.59% compared to traditional technologies. These findings robustly validate the methodology's effectiveness, paving the way for more sustainable urban energy management practices.

Climate change and increased urban population are two major concerns for society. Moving towards more sustainable energy solutions in the urban context by integrating renewable energy technologies supports decarbonizing the energy sector and climate change mitigation. A successful transition also needs adequate consideration of climate change including extreme events to ensure the reliable performance of energy systems in the long run. This review provides an overview of and insight into the progress achieved in the energy sector to adapt to climate change, focusing on the climate resilience of urban energy systems. The state-of-the-art methodology to assess impacts of climate change including extreme events and uncertainties on the design and performance of energy systems is described and discussed. Climate resilience is an emerging concept that is increasingly used to represent the durability and stable performance of energy systems against extreme climate events. However, it has not yet been adequately explored and widely used, as its definition has not been clearly articulated and assessment is mostly based on qualitative aspects. This study reveals that a major limitation in the state-of-the-art is the inadequacy of climate change adaptation approaches in designing and preparing urban energy systems to satisfactorily address plausible extreme climate events. Furthermore, the complexity of the climate and energy models and the mismatch between their temporal and spatial resolutions are the major limitations in linking these models. Therefore, few studies have focused on the design and operation of urban energy infrastructure in terms of climate resilience. Considering the occurrence of extreme climate events and increasing demand for implementing climate adaptation strategies, the study highlights the importance of improving energy system models to consider future climate variations including extreme events to identify climate resilient energy transition pathways.

The building sector is currently responsible of 40% of global final energy consumption, influencing the broader energy system in terms of new electricity and heat capacity additions, as well as distribution infrastructure reinforcement. Current building energy efficiency potential is largely untapped, especially at the local level where retrofit interventions are typically enforced, neglecting their potential synergies with the entire energy system. To improve the understanding of these potential interactions, this paper proposes a methodology that links dynamic building simulation and energy planning tools at the urban scale. At first, a detailed bottom-up analysis was conducted to estimate the current and post-retrofit energy demand of the building stock. The stock analysis is further linked to a broader energy system simulation model to understand the impact of building renovation on the whole urban energy system in terms of cost, greenhouse gas emission, and primary energy consumption up to 2050. The methodology is suited to analyze the relationship between building energy demand reduction potential and clean energy sources’ deployment to shift buildings away from fossil fuels, the key priority for decarbonizing buildings. The methodology was applied to the case study city of Torino, Italy, highlighting the critical role of coupling proper building retrofit intervention with district-level heat generation strategies, such as modern district heating able to exploit low-grade heat. Being able to simulate both demand and supply future alternatives, the methodology provides a robust reference for municipalities and energy suppliers aiming at promoting efficient energy policies and targeted investments.

Purpose of Review Cities are crucial for an effective energy transition, yet national transition exercises often overlook local urban conditions. This paper reviews the assessment of hydrogen integration in urban energy system models and the use of Geographical Information Systems (GIS) to facilitate high spatial resolution modelling.Recent FindingsEmbedded GIS frameworks can unmask local conditions crucial for energy transition planning, providing valuable insights to support informed decision-making. We found a gap in holistic modelling of the hydrogen supply chain and sector coupling. Furthermore, most studies lack future cost projections, and GIS is often underutilised. We also detected a general lack of transparency and low temporal resolution.SummaryThis review assesses urban hydrogen integration, highlighting how geospatial approaches are used to addresses the lack of local information in recent energy system modelling, Future research should enhance GIS use, integrate sector coupling, and improve transparency and temporal resolution to better understand the optimal integration of hydrogen.

Industrial process integration based on mixed integer linear programming has been used for decades to design and improve industrial processes. The technique has later been extended to solve multi-period and multi-scale problems for the design of urban energy systems. Assistance is indeed required for the elaboration of coordinated investment scheduling strategies to promote renewable and efficient urban energy infrastructure shaping the future energy context for the next decades. Major energy consumers, such as hospital complexes, airports, or educational campuses can act as a driving force for the development of renewable energy cities by attracting profitable large-scale energy networks and infrastructure. The proposed methodology generates optimal alternatives for the replacement, in a long-term perspective, of the various energy supply units and systems considering the evolution of the energy demand and the availability of the energy resources. Energy integration techniques are coupled to a parametric multi-objective optimization routine to select and size the energy equipment with both financial profitability and CO2 emission reduction as objectives. The originality of the developed method lies in the integration of a multi-period mixed integer linear programming formulation to generate long-term investment planning scenarios. The method has been demonstrated on a complex of eight hospitals totaling 466,000 m2 and an operating budget of 1.85 billion USD per year. The energy integration of new centralized and decentralized equipment has been evaluated on a monthly basis over four periods until the year 2035. The results show that among the four scenarios identified, the most optimistic alternative allows to decrease the final energy consumption of about 36%, cut the CO2 emissions by a half, multiply the renewable energy share by a factor 3.5 while reducing the annual total cost by 24%. This scenario considers mainly the integration of a very low temperature district heating with decentralized heat pumps to satisfy the heat requirements below 75°C, as well as heat recovery systems and the refurbishment of about 33% of the building stock.

Methods for reducing large speed differences in traffic streams