Municipal Energy Systems Research Articles

What drives energy storage deployment in local energy transitions? Stakeholders’ perspective

The global shift towards decentralised energy systems has assigned municipalities a key role in achieving national climate neutrality objectives. As the main stakeholders in the local energy transition, municipalities are responsible for the decarbonization of the local energy system through the extensive integration of renewable energy sources into existing systems. However, this integration requires new approaches and system adjustments, such as energy storage deployment, to satisfy the variable nature of renewable energy sources. The integration of novel solutions, such as energy storage, is difficult because of the diverse range of stakeholders involved, each with their own perceptions and expertise. This study uses the Fuzzy Cognitive Mapping (FCM) methodology to analyse the mental models of different stakeholders regarding their perceived importance of different factors influencing the implementation of energy storage in municipalities. The approach of this study enables a better understanding of municipal energy systems and its dynamics. The results reveal that support schemes such as subsidies and awareness campaigns are key to all stakeholders. Municipalities tend to focus on local needs and technological solutions, while energy experts prioritize technical aspects and national policies. Municipalities address challenges linearly, missing interconnections, whereas energy experts consider feedback loops and system requirements. The study highlights the need for common ground to drive effective policy and infrastructure development. The results could be used to facilitate discussions with policy makers on why energy storage is important and what policy measures should be considered to accelerate its deployment.

Developing energy system scenarios for municipalities - Introducing MUSEPLAN

The value of energy system scenarios is increasingly asserted in a decentralised and municipal context. There is, however, a lack of suitable tools for designing such scenarios, particularly tools that empower local planning practitioners in active participation. With this study, we introduce a novel tool designed specifically for municipal energy system modelling, thus bridging the gap between model developers and planning practitioners. The applicability and suitability of the new MUSEPLAN tool is investigated through its application in a case municipality, revolving around the needs of planning practitioners, supporting the build-up of modelling capacity, and focusing on the practical development of energy system scenarios. MUSEPLAN draws on the specialist simulation model EnergyPLAN but provides an environment for integrated design and comparison of multiple scenarios while reducing the complexity through discarding some of the more advanced options. In conclusion, MUSEPLAN resolves the identified challenges to the integration of energy system modelling in municipal energy planning, while simplifying the modelling and scenario evaluation process.

Municipal energy system modelling – A practical comparison of optimisation and simulation approaches

This paper investigates the impact of applying optimisation and simulation approaches for energy system modelling and scenario design in a municipal context. In doing so, the previous understanding of what constitutes “optimisation” and “simulation” is expanded with further distinctions and it is documented how the outlined modelling approaches are applied in the existing literature. In a practical comparison, it is tested how the choice of modelling approach influences the design of future energy system scenarios for a municipal case study. The energy system scenarios and results obtained from a proposed stepwise simulation approach are compared to an established multi-objective optimisation approach. The results show that for the investigated municipal case it is possible to obtain results with a simulation-based approach that are comparable to the results obtained from multi-objective optimisation. Ultimately, the choice of modelling approach is a complex issue in which modellers must consider the necessary degree of modelling freedom, stakeholder involvement, and available system knowledge. Modellers need to consider not only what tool to use, but also how it is used; a tool can be used for both optimisation and simulation, and both can be valid approaches for developing future energy system scenarios.

Analysing municipal energy system transformations in line with national greenhouse gas reduction strategies

Climate change mitigation and transformation strategies with expansion targets for renewable energy sources are defined at the national level. Due to the decentralised character of these sources, local energy system planning plays an important role. However, local communities often lack the capacity to develop energy concepts and thus exploit local renewable potentials consistently. This study develops a highly transferable methodology for deriving local energy system transformation scenarios in line with national greenhouse gas reduction strategies. Thus, an energy system optimisation model is substantially extended to collectively optimise the transformation of final energy demand in the residential, industry, tertiary and transport sectors, as well as established and niche greenhouse gas reduction technologies. Here, a focus is set on the building stock transformation, and a stochastic model is presented to better grasp and represent the dynamic developments and heterogeneity of the local building stock. Based on superordinate parameters such as retrofit rates and heating technology diffusion, the stochastic model generates informative building stock scenarios that are used as input for the developed energy system optimisation model. Exemplarily, the model is applied to the central European city of Karlsruhe. The results show that an increase of the retrofit rate to 2 %/a and strong electrification of the heat supply in the building sector is economically and environmentally beneficial. Furthermore, an accelerated expansion of photovoltaics compared to the national expansion rate can save costs and CO2 emissions. Building on the methodology presented, transferable infrastructure models for the electricity, gas and district heating network should be developed that can be used to assess the feasibility of the transformation paths determined by the methodology presented.

Planning and Energy–Economy–Environment–Security Evaluation Methods for Municipal Energy Systems in China under Targets of Peak Carbon Emissions and Carbon Neutrality

In order to mitigate the negative effects of global climate change, the Chinese government has committed to achieving peak carbon emissions by 2030 and carbon neutrality by 2060. Since municipal cities are the bottom administrative level for drawing up development plans, it is necessary and important to conduct decarbonization pathway research on municipal energy systems (MESs). However, there is little research on decarbonization at the municipal level, and the impact of development paths in each forecast scenario is mostly based on expert evaluation and qualitative assessment. Therefore, this study established a complete decarbonization framework for MESs, including general research procedures, models, and a sustainable evaluation method. The models of energy consumption and carbon emission were adapted and improved for MESs. In order to quantitatively evaluate the energy system development for each scenario, we proposed an energy–economy–environment–security (3E–S) evaluation method, in which principal component analysis (PCA) was adopted for multi-criterion decision making. According to the analysis results of the case city in Guangdong, this evaluation method was proved to be an effective way to identify the factors that may influence coordinated development. By adjusting the relevant parameters and factors in the model, the optimal decarbonization pathway can be found to promote sustainable and coordinated development, thus helping government decision makers to quantitatively evaluate planning paths.

Impact of CO2 reduction targets on the integrated planning of municipal multi-energy carrier systems with grid infrastructures and energy conversion units

National climate protection goals require the emission reduction in municipal energy supply systems. Those systems include energy conversion units like heatings, energy storages, and grids for electricity, gas, and heat. This paper presents a mixed-integer linear optimization model for the integrated and multi-modal planning of such municipal energy systems to reach a defined CO2 emission limit with the least-cost system design. The exemplary application of the model to a study case with 3900 buildings shows that the flexible hybrid energy system resulting without emission restrictions gradually transforms into an inflexible system solely relying on pellet heaters and photovoltaic units when tightening the emission limit by just a few percentage points.

Pathways for sustainable municipal energy systems transition: A case study of Tangshan, a resource-based city in China

Cities consume most of the global energy and account for approximately 75% of global CO2 emissions. Moreover, resource-based cities tend to consume higher amounts of fossil fuel and produce higher carbon emissions than other cities, whereas there are still insufficiencies about energy carbon reduction in resource-based cities in developed urban agglomerations. Therefore, it is necessary to explore the energy planning of such cities to achieve carbon peaking and carbon neutrality, and this is crucial for achieving carbon neutrality in urban agglomerations. This study aims to apply a scenario-based analysis approach to a resource-based heavy industrial city in China, Tangshan, based on the Long-range Energy Alternative Planning model, to explore Tangshan's future energy consumption, generation, and associated carbon emissions from 2010 to 2050. The impacts of different energy policies are analyzed for the Tangshan energy system by considering four scenarios. Under each scenario, energy consumption increased steadily by 2050, but the growth rate is different. The business as usual scenario is the fastest, and the low-carbon scenario is the slowest. In the comprehensive and integrated low-carbon transition scenarios, CO2 is expected to peak at 298.34 million tons (Mt) in 2028. The main industrial sectors of Tangshan with high output value, high energy consumption, and high carbon emissions include smelting and pressing of ferrous metals, petroleum processing and coking, raw chemical materials and chemical products, etc. Combining Tangshan's coal resource endowment, the development of renewable energy, and introducing advanced technology can effectively reduce carbon emissions and increase the diversity of energy supply. We analyzed the cost-benefit of the energy system and found that the implementation of carbon capture and storage technology could effectively reduce carbon emissions by 219.62 Mt and increased costs by 563.12 billion yuan. The research could provide a scientific basis for the medium and long-term energy sustainable transformation of resource-based cities, especially for resource-based cities in urban agglomerations.

Is total system cost minimization fair to all the actors of an energy system? Not according to game theory

A common approach to energy system optimization is to minimize overall costs at system level, regardless of the actors actually bearing those costs. This paper presents an approach inspired by Nash game theory concepts, in which the actors involved in an energy system determine their optimal strategies according to their own economic interests (profit functions) in a non-cooperative or in a cooperative way. A simple case study, considering an electric utility and individual heating consumers in the municipal energy system of a small town in northern Sweden, shows the differences between the two approaches. The game theory approach is able to represent more realistic interactions among the actors of an energy system, fair in fulfilling their conflicting economic interests, and, therefore, a more suitable tool for decision makers evaluating the impacts of policy instruments.

County Clustering with Bioenergy as Flexible Power Unit in a Renewable Energy System

The pressure on the energy sector to reduce greenhouse gas emissions is increasing. In the light of current greenhouse gas emissions in the energy sector, further expansion of renewable energy sources (RES) is inevitable to reduce emissions and reach the climate goals. This study aims at investigating structural characteristics of German counties regarding advantages for self-sufficient power systems based on RES. The modelling of the power sector based on RES is coupled with a cluster analysis in order to draw a large-scale conclusion on structural characteristics beneficial or obstructive for municipal energy systems. Ten clusters are identified with the Ward algorithm in a hierarchical-agglomerative method. The results underline a further need for RES expansion projects in order to close the gap between supply and demand. Only then, bioenergy can effectively balance the offset and support a truly self-sufficient local energy system. While the model results indicate that the majority of the counties are suitable for further expansion, this suitability is to be questioned in cluster 10. High population density is a critical characteristic, because with it come both a high demand and limited sites for further RES expansion projects.

Life Cycle Assessment of Biogas Production from Unused Grassland Biomass Pretreated by Steam Explosion Using a System Expansion Method

Reforestation is a threat to permanent grasslands in many alpine regions. Using these areas to produce biogas energy may help to preserve these important landscapes and save fossil fuels by adding a renewable local heat and electricity source. This case study compares (a) a status quo (SQ) reference scenario with heating oil, wood-chips, and grid electricity as municipal energy sources, and (b) a hypothetical local biogas (LB) scenario (to also be used as a municipal energy source) based on a 500-kWel biogas plant with steam explosion pretreatment. Here, hay from previously unused grassland is the main biogas substrate, whereas, in the reference SQ scenario, these grasslands remain unused. Life cycle assessment (LCA) results for LB and SQ scenarios are significantly different at p < 0.05 in all six impact categories. In three categories, the LB scenario has lower impacts than the SQ scenario, including climate change (0.367 CO2-eq kWhel-1 versus 0.501 CO2-eq kWhel-1). Dominant contributions to climate change in the SQ scenario are from the extant municipal energy sources that the LB biogas plant would replace; in the LB scenario, important contributions include unburned methane from the biogas plant, as well as CO2 emissions from hay production machines. In summary, important environmental impacts can be reduced and alpine grasslands can be preserved by biogas production from that grass. The advantages of integrating a local biogas plant in municipal energy and waste systems depend strongly on the extant municipal energy system characteristics.

Identification of Potential Off-Grid Municipalities With 100% Renewable Energy Supply for Future Design of Power Grids

An increasing number of municipalities are striving for energy autonomy. This study determines in which municipalities and at what additional cost energy autonomy is feasible for a case study of Germany. An existing municipal energy system optimization model is extended to include the industrial, commercial and personal transport sectors. Multiple regression methods are benchmarked in order to identify the model best suited for the transfer of individual optimization results to a large proportion of German municipalities. The resulting levelized cost of energy (LCOE) from the optimization of representative case study municipalities are transferred using energy-relevant indicators. The study demonstrates that energy autonomy is technically feasible in 6,314 (56%) municipalities. Thereby, the LCOEs increase in the autonomous case on average by 0.41 €/kWh compared to the minimum cost scenario. Apart from energy demand, base-load-capable bioenergy and deep geothermal energy have the greatest influence on the LCOEs. Overall, it appears that municipal energy autonomy is not economically viable under current framework conditions. This study represents a starting point for defining possible scenarios in studies of future national energy system or transmission grid expansion planning, which for the first time consider completely energy autonomous municipalities.

Modelling Grid Constraints in a Multi-Energy Municipal Energy System Using Cumulative Exergy Consumption Minimisation

Efficiency measures and the integration of renewable energy sources are key to achieving a sustainable society. The cumulative exergy consumption describes the resource consumption of a product from the raw material to the final utilisation. It includes the exergy expenses for energy infrastructure as well as the imported energy. Since consumers and renewable potentials are usually in different locations, grid restrictions and energy flows have a significant impact on the optimal energy system design. In this paper we will use cumulative exergy minimisation together with load flow calculations to determine the optimal system design of a multi-cell municipal energy system. Two different load flow representations are compared. The network flow model uses transmission efficiencies for heat, gas and electricity flows. The power flow representation uses a linear DC approximated load flow for electricity flows and a MILP (mixed integer linear programming) representation for heat and gas flows to account for the nonlinear pressure loss relation. Although both representations provide comparable overall results, the installed capacities in the individual cells differ significantly. The differences are greatest in well meshed cells, while they are small in stub lines.

Factors That Contribute to Changes in Local or Municipal GHG Emissions: A Framework Derived from a Systematic Literature Review

The changes observed in a municipal or local energy system over a period of time is due a number of concurrent dynamics such as the local social and economic trends, higher-level policies (e.g., national), and the local policies. Thus, a thorough identification and characterization of the many factors of change is key for an adequate assessment of the effectiveness of policies adopted at the local level, as well as for future planning. Such thorough identification and characterization of the factors that are determinant for the evolution of the local energy system is the content of this paper. The identification is performed through a systematic literature review, followed by a synthesis process. The factors identified are grouped into the categories of local context, local socio-economic and cultural evolution, higher-level governance framework, and local climate change mitigation actions. They are represented through a set of measurable variables. The factors and respective variables can be used to improve the disaggregation of changes in the local energy system into individual causes, leading to a better assessment of the evolution over time.

Reviewing Municipal Energy System Planning in a Bibliometric Analysis: Evolution of the Research Field between 1991 and 2019

In the context of the energy transition, energy system planning is becoming increasingly relevant for decentralized systems. Motivated by the strong increase of publications on municipal energy system planning (MESP), these studies are subjected to a bibliometric analysis in this paper. The 1235 articles, which are based on the Web of Science database, are examined using the R-tool bibliometrix. The study shows that China is the most important contributor with 225 articles, followed by the USA (205) and Germany (120). Most cross-country collaborations were conducted between China and Canada, focusing mainly on uncertainties in MESP. Among the institutions, the North China Electric Power University is responsible for most articles (42). The core journals on MESP are Energy, Applied Energy, Energy Policy, Energies and Renewable Energy, which published 37% of the 1235 articles. Publications on MESP focus on renewable energies, optimization and hybrid energy systems. Furthermore, district heating seems to be a core topic in MESP and is addressed in three of the top five most cited articles. The demonstration of global research trends in MESP can support researchers in identifying the relevant issues regarding this expanding and transforming research area.

Towards Optimal Sustainable Energy Systems in Nordic Municipalities

Municipal energy systems in the northern regions of Finland, Norway, and Sweden face multiple challenges: large-scale industries, cold climate, and a high share of electric heating characterize energy consumption and cause significant peak electricity demand. Local authorities are committed in contributing to national goals on CO2 emission reductions by improving energy efficiency and investing in local renewable electricity generation, while considering their own objectives for economic development, increased energy self-sufficiency, and affordable energy costs. This paper formulates a multi-objective optimization problem about these goals that is solved by interfacing the energy systems simulation tool EnergyPLAN with a multi-objective evolutionary algorithm implemented in Matlab. A sensitivity analysis on some key economic parameters is also performed. In this way, optimal alternatives are identified for the integrated electricity and heating sectors and valuable insights are offered to decision-makers in local authorities. Piteå (Norrbotten, Sweden) is used as a case study that is representative of Nordic municipalities, and results show that CO2 emissions can be reduced by 60% without a considerable increase in total costs and that peak electricity import can be reduced by a maximum of 38%.

Optimal Municipal Energy System Design and Operation Using Cumulative Exergy Consumption Minimisation

In developed countries like Austria the renewable energy potential might outpace the demand. This requires primary energy efficiency measures as well as an energy system design that enables the integration of variable renewable energy sources. Municipal energy systems, which supply customers with heat and electricity, will play an important role in this task. The cumulative exergy consumption methodology considers resource consumption from the raw material to the final product. It includes the exergetic expenses for imported energy as well as for building the energy infrastructure. In this paper, we determine the exergy optimal energy system design of an exemplary municipal energy system by using cumulative exergy consumption minimisation. The results of a case study show that well a linked electricity and heat system using heat pumps, combined heat power plants and battery and thermal storages is necessary. This enables an efficient supply and also provides the necessary flexibilities for integrating variable renewable energy sources.

Spatial high-resolution socio-energetic data for municipal energy system analyses

In the context of the energy transition, municipalities are increasingly attempting to exploit renewable energies. Socio-energetic data are required as input for municipal energy system analyses. This Data Descriptor provides a compilation of 40 indicators for all 11,131 German municipalities. In addition to census data such as population density, mobility data such as the number of vehicles and data on the potential of renewables such as wind energy are included. Most of the data set also contains public data, the allocation of which to municipalities was an extensive task. The data set can support in addressing a wide range of energy-related research challenges. A municipality typology has already been developed with the data, and the resulting municipality grouping is also included in the data set.

Assessing the contribution of simultaneous heat and power generation from geothermal plants in off-grid municipalities

A growing number of German municipalities are striving for energy autonomy. Geothermal plants are increasingly constructed in municipalities in order to exploit the high hydrothermal potential. This paper analyses the potential contribution of simultaneous geothermal power and heat generation in German municipalities to achieving energy autonomy. A linear regression estimates the achievable hydrothermal temperatures and the required drilling depths. Technical restrictions and cost estimations for geothermal plants are implemented within an existing linear optimisation model for municipal energy systems. Novel modelling approaches, such as optimisation with variable drilling depths, are developed. The new approach is validated with data from existing geothermal plants in Germany, demonstrating a Root Mean Squared Error of about 15%. Eleven scenarios show that achieving energy autonomy is associated with at least 4% additional costs, compared to scenarios without it. The crucial role of geothermal plants in providing base load heat and power to achieve energy autonomy is demonstrated. The importance of simultaneous modelling of electricity and heat generation in geothermal plants is also evident, as district heating plants reduce the costs, especially in municipalities with high hydrothermal potential. Further work should focus on the optimal spatial scale of the system boundaries and the impact of the temporal resolution of the analysis on the costs for achieving energy autonomy.

Developing a municipality typology for modelling decentralised energy systems

One solution to the large-scale integration of renewable energies could be decentralised autonomous municipal energy systems. Several studies have already analysed the technical and economic implications of the mainly decentralised future energy system, but most are restricted in their insights by limited temporal and spatial resolution. This study employs a cluster analysis to develop a municipality typology in order to analyse the techno-economic suitability of municipalities for autonomous energy systems. A total of 34 socio-technical indicators are employed at the municipal level, with a particular focus on the sectors of Private Households and Transport, and the potentials for decentralised renewable energies. Selected quantitative cluster validation methods are employed alongside qualitative criteria to determine the optimal number of clusters. This results in a total of ten clusters, which show a large variation as well as some overlap with respect to specific indicators. An analysis of the municipalities from three German renewable energy projects “Energy Municipalities”, “Bioenergy Villages” and “100% Renewable Energy Regions” shows that in eight of the ten clusters municipalities are aiming for energy autonomy (in varying degrees). It is challenging to differentiate between the clusters regarding readiness for energy autonomy projects, however, especially if the degree of social acceptance and engagement for such projects is to be considered. To answer the more techno-economical part of this question, future work will employ the developed clusters in the context of an energy system optimisation. Insights gained at the municipal level will then be qualitatively transferred to the national context to assess the implications for the whole energy system.

Optimization of Municipal Energy Systems with the Use of an Intelligent Analytical System

The paper presents the analytical and consultancy system which aims at a complex, comprehensive, multi-criteria energy performance analysis of a given building or a group of buildings and at making a recommendation for an energy source with regard to CO<sub>2</sub> emission and investment costs determined on the basis of indicators included in the knowledge databases. The analytical and consultancy system employs advanced energy performance computer simulations of buildings as well as innovative analytical algorithms worked out and contributed by the authors, including those based on the knowledge base developed on the grounds of performance data from selected buildings of various types situated in a dozen or so cities of different population in Poland.