This study evaluates the long-term impact of integrating an energy hub into a district heating system, with a particular focus on system autonomy, CO₂ emissions reduction, and cost dynamics up to 2050. A scenario-based approach was applied to assess three alternative development pathways, combining building renovation measures with different levels of heat supply decarbonization and energy resource diversification. The analysis considers changes in heat production structure, emissions balance, and economic performance under varying technological and market conditions. The results indicate that by implementing the energy hub, the share of purchased heat energy decreases from approximately 70% in 2023 to 35% in 2050, while the share of self-produced heat energy increases from approximately 30% to 65%. The emission analysis shows that energy efficiency measures in the building sector alone provide limited mitigation potential, achieving only moderate CO₂ reductions. Substantially higher emission reductions, up to 36% by 2050, are achieved when building renovation is combined with a diversified and decarbonized heat supply, including the replacement of natural gas with low-carbon heat sources. The economic assessment reveals a clear trade-off between cost efficiency and strategic energy independence. Scenarios with lower initial investments and increased reliance on wood-chip-based heat remain the most cost-effective option throughout the analysed period, while technologically advanced solutions with higher upfront costs, such as the integration of an energy hub with synthetic methane production, have higher annual costs despite additional revenues from electricity sales. Sensitivity analysis confirms that natural gas prices remain the dominant cost driver, although the implementation of the energy hub and synthetic methane production progressively reduces the systems vulnerability to gas price volatility. The findings highlight the necessity of an integrated approach to district heating system transformation, demonstrating that long-term emission reductions, energy security, and economic resilience can only be achieved through the combined approach to building energy efficiency, heat supply decarbonization, and strategic long-term planning.
This 50th volume of the International Journal of Sustainable Energy Planning and Management presents contemporary work from the energy planning arena with focus on the planning of renewable energy assets under grid and land constraints, and district heating decarbonisation from a hub-perspective. The two last papers in this volume address different aspects of photovoltaic development; Virtual Power Plant development in Bahrain and agrivoltaic development prospects in Indonesia.
The increasing demand for clean and cost-effective energy has driven the development of hybrid renewable energy systems, particularly those combining wind and solar power. This paper introduces a practical optimization model for sizing hybrid onshore wind and photovoltaic power plants, incorporating critical systemic constraints such as land availability, grid capacity, and natural complementarity between energy sources. Unlike traditional models focused solely on minimizing cost or maximizing energy output, this approach considers the temporal anti-correlation between wind and photovoltaic resources to enhance grid infrastructure utilization. Developed in Microsoft Excel® with the Solver add-in, the model is accessible and easy to implement for energy planners and developers. A real case study in Sento Sé, Bahia State in Brazil, where wind and solar generation patterns are strongly anticorrelated, demonstrates the effectiveness of the model. Results indicate that the proposed hybrid configuration reduced the annualized system cost from 237.6 M USD to 161.6 M USD compared to standalone wind solution, representing a cost reduction of approximately 32%. Furthermore, grid infrastructure utilization increased from 64% to 84%, highlighting the benefit of incorporating resource complementarity into the system sizing. These outcomes highlight the value of well-designed hybrid systems, maximizing renewable integration without overloading existing infrastructure. The model offers a replicable decision-making tool for early-stage project design and capacity expansion planning, supporting more efficient and sustainable energy transitions.
Heating is one of Europe’s most energy-intensive sectors. District heating (DH) offers a key pathway to decarbonisation by integrating renewable energy (RE) and excess heat (EH) and reducing fossil fuel dependency. However, as heat demand and supply vary geographically, planning DH expansion requires understanding the spatial variability of heat demand, resources and cost-effectiveness of the systems. This study presents a geospatial analysis of DH potential, combining RE/EH resources and investment costs to model the distribution and economic feasibility of DH systems. Key contributions include a harmonised assessment of DH potential across European Union countries, a prioritisation framework that identifies the most cost-effective locations for DH, and an analysis of regional differences in heat market share. These insights are supported by high-resolution mapping that highlights strategic priority regions at the NUTS 2 level. The study also improves the accuracy of the Pan-European Heat Atlas, making it available as an open-access dataset and tool. The results identify regional variations in DH potential and RE/EH availability, highlighting local opportunities for efficient deployment. These findings support policymakers, regional planners and researchers in designing strategies to accelerate DH deployment toward a 55% DH market share across Europe.
District heating grids (DHGs) offer substantial potential for decarbonising the heating sector, which accounts for around 40% of Europe’s total energy consumption. Although DHGs are a mature technology, the integration of renewable energy (RE) remains limited. This study evaluates Hybrid Network Solutions (HNS) through a one-year simulation of three heat supply scenarios in a southern German town. Two innovative HNS concepts incorporate rooftop photovoltaic (PV) systems and decentralised thermal energy storage (TES) to enable sector coupling via electric heating elements and air-to-water heat pumps (HPs). Scenario 1 integrates heat supply through a DHG with decentralised Power-to-Heat (P2H) units, enabling greenhouse gas (GHG) reductions by utilizing surplus PV electricity. Scenario two introduces a dual-grid structure with a low-temperature network supplied by a large groundwater heat pump and a high-temperature DHG using waste heat. While this configuration reduces final energy demand, it results in higher GHG emissions due to reliance on grid electricity with a high primary energy factor. The findings highlight the efficiency potential of HPs and the importance of aligning heat sector electrification with power sector decarbonisation. HNS concepts can serve as scalable models for sustainable district heating, provided that a renewable electricity supply and intelligent operational strategies are ensured.
The transition to a sustainable energy system requires the consideration of all available renewable heat sources. This study assesses the potential of wastewater and river heat for district heating networks in the federal state of Hesse, Germany, considering the seasonality of available heat and heat demand. Using standardised temperature and flow profiles for 443 wastewater treatment plants as well as interpolated river temperature and flow data for approx. 1,500 km of rivers, the study quantifies the heat extraction potential. By matching with heat demand profiles at daily resolution, based on forecast heat demand data for the year 2045, the long-term usable potential is determined. Possible heat network areas are identified based on the heat density indicator. For all building blocks with heat densities above 175 MWh/(ha·a), the usable heat potential amounts to 4.5 TWh/a for river heat pumps and 4.9 TWh/a for wastewater heat pumps. Applying a higher threshold of 415 MWh/(ha·a) reduces the potential to 1.3 TWh/a and 2.4 TWh/a, respectively. The usable potential of both sources together corresponds to 11 % to 28 % of Hesse's heating demand for space heating and domestic hot water. Using a new 1D energy balance model for an exemplary river it is shown that the heat extraction from the river is acceptable concerning cumulative cooling. The study provides municipalities with a comprehensive database that facilitates the incorporation of these underutilised heat sources into their mandatory heat planning. The methodology presented can be adapted to other regions.
This 49th volume of the International Journal of Sustainable Energy Planning and Management presents articles from the 11th Smart Energy Systems Conference held in Copenhagen, Denmark in 2025. The conference invites academia, industry, consultancy, and utilities to engage and discuss the transition of the energy system. District heating has always been a strong focus point of the conference, as is also evident in the present 49th volume of the IJSEPM. Topics presented in this volume include a study on alternative heat sources for heat pumps in district heating, such as wastewater and river water. District heating continues to be a focal point, in a study exploring hybrid network solutions for further development of district heating systems, and in a study on decarbonisation of combined district heating and cooling systems. Also connected to district heating, this volume presents work on novel methods for estimations of heat demand and heat sources for district heating across the European Union, in addition to a study on the mapping of waste heat potentials, and lastly, the global warming potential of district heating in Finland. Finally, this volume presents work on industry transformations and prominent barriers to this transformation, and a rare study on the maritime sector and the modelling of sustainable fuel pathways.
Municipal heat planning is becoming a mandatory element of local climate policy in Germany, yet many smaller municipalities lack geospatial tools that are transparent, reproducible and aligned with the German Heat Planning Act (WPG). This paper presents F|Heat, an open-source QGIS extension that supports early-stage municipal heat planning by automating data acquisition, building-level heat-demand preparation, heat-density and heat-line-density analyses, preliminary district-heating network routing, pipe dimensioning, heat-loss estimation and load-profile generation. The method is demonstrated for a district in Barntrup, North Rhine-Westphalia, Germany. The case study connects 268 buildings with an annual heat demand of 11.9 GWh and generates a 9.1 km preliminary network. Simulated annual heat losses amount to 1.6 GWh with standard insulation and 1.4 GWh with enhanced insulation. Using DN-specific network investment assumptions, the annualised network cost contribution is estimated at 0.042 EUR·kWh-1. The results show that F|Heat can provide a reproducible GIS-based workflow for suitability assessment, status-quo analysis and preliminary district-heating area assessment. The tool does not replace detailed techno-economic optimisation, heat-source assessment or engineering design, but narrows the gap between statutory heat planning requirements and the data-processing capacity of municipalities.
Climate change is expected to reduce heating demand in Finnish buildings, impacting district heating (DH) systems. This study models small, medium, and large DH systems for the years 2030 and 2050 using Representative Concentration Pathway (RCP) climate scenarios. The analysis uses energyPRO to simulate system operations based on fuel price prioritization, comparing future scenarios to a 2023 baseline. The transition from high-emission systems to sustainable energy sources—such as waste heat, electric boilers, and nuclear—poses challenges for revenue and energy security. While national-level studies exist, local-level insights are limited. Results show that reduced heat demand can lead to significant revenue losses in current systems, although renewable heat production increases. Smart future systems that minimize fossil fuel combustion and rely on biomass-based renewables maintain more stable revenues due to lower emission costs and consistent fuel pricing. These findings support strategic planning for sustainable, cost-effective DH systems aligned with national and EU climate goals.
In the maritime sector, sustainable alternative fuels derived from biological and non-biological origin such as hydrogen, ammonia, and methanol show high potential for novel propulsion technologies such as solid oxide fuel cells. Since transitioning to new fuels may require high investments, decision-makers and local municipalities need a systematic approach to identify the most relevant fuel pathways for their prerequisites. However, a modelling approach including fuel production, transport, demand, time-resolved supply rates for testing and comparing sustainable alternative fuels is still lacking. Here, a Python library called multi-fuel pathway explorer (MFPE) was developed, for fuel-cell applications in the maritime sector. The library offers the possibility of rapid screening and modelling of high-potential pathways depending on the constituents of the target port environment, allowing for in-depth evaluation of technical details compared to commonly applied life-cycle assessment (LCA) or techno-economical assessment (TEA) tools. For demonstration, a case study was set up at the port of Rotterdam to evaluate fuel pathways by calculation of selected key performance indicators (KPIs). Results demonstrate that the model is applicable on complex multi-fuel systems to compare fuel pathways, identify system-level bottlenecks, and analyse time-resolved dependencies between fuel demand and supply along the pathway.
The transition towards climate-neutral energy systems requires exploiting local renewable and residual energy sources to decarbonise the heating and cooling sector. District Heating and Cooling Networks (DHCNs) are key infrastructures for integrating Waste Heat (WH) into urban energy systems, but comprehensive spatial data on WH availability are often lacking and difficult to retrieve. This study develops a methodology for mapping WH potential from both industrial and tertiary sectors, providing critical information for the decarbonisation and expansion of existing DHCNs. The approach combines open geographic datasets, statistical information, and literature-based coefficients within a structured workflow to estimate potential annual WH availability at different temperature levels, along with its hourly profiles. The outcome is a detailed spatio-temporal characterisation of WH, presented in a geospatial package containing the georeferenced annual WH potential, coupled with a dataset of hourly profiles for each activity during a typical meteorological year. The methodology is applied to a case study in Milan with three main objectives: first, to test and validate the reliability proposed approach; second, to discuss the implications of WH integration in the development of a DHCN modernisation scenario; and third, to assess the uncertainty of waste heat potential estimation through comparison with Danish and Austrian reference databases. Thus, this study offers a replicable framework for WH potential mapping, supporting decision-making and planning for sustainable DHCNs and urban energy transition strategies.
Various renewable and infrastructure options are available for decarbonising the heating sector and at the same time cooling is getting increasingly important. Existing approaches and tools for urban heat planning often require detailed modelling and often only address a limited range of heating and cooling (H&C) options. This paper introduces a simplified approach for quick assessment of 4th generation district heating (4GDH), thermal source networks and individual solutions. The approach uses publicly available datasets, a seasonal representation of energy balances and levelised cost indicators under limited early-stage data availability. The approach is validated by comparison with a detailed hourly feasibility study for a large-scale 4GDH case study in the UK. Cost deviations are within pre-feasibility screening ranges (± 30%), while component-level capacities and costs can differ due to deterministic peak sizing and network correlations, which result from the simplified representation of peak loads and network structures. Since these differences are generally acceptable, the proposed approach enables rapid, transparent comparison of H&C systems and thus can support early planning decisions.
As part of the European Green Deal, Germany is committed to greenhouse gas neutrality by 2045. To accommodate these goals, manufacturing enterprises are aiming to futureproof their sites through site transformations towards sustainability. Such efforts are affected by an inherent competition for usable space, as each successive transformation changes the overall site composition. Despite economic sustainability having the highest priority for enterprises, land is nonetheless being allocated to socio-environmental measures. To gauge current industrial efforts for sustainable transformation, a interview study with 19 experts was conducted. The experts represented the fields of site planning, facility management, and sustainability management. The study primarily focused on plans for next generational energy systems, including challenges faced during their planning and execution, supplemented by how land is used for further sustainability measures. The interviews were analyzed using Kuckartz’ qualitative content analysis. The results show proactive engagement by enterprises to meet climate goals ahead of regional policies. Within this scope, the goal of ensuring economic competitiveness is pursued through a variety of different means, such as security of energy supply, self-sufficiency, adaptability to new technologies and regulations, and staff retention. Organizational challenges were found to outweigh financial ones.
Stakeholder engagement, data collection, and more importantly, the analysis of the collected data and their implementation are critical components for an effective energy system modelling. The energy modelling needs to also address local specificizes as in this case focused on African continent these needs to include specific energy challenges, such as inadequate access to electricity, unreliable energy supply coupled with a heavy reliance on traditional biomass. Stakeholder views on the energy modelling process within the three African regions with specific case studies in Morocco, Mozambique and the Niger river basin in Mali are investigated. To effectively capture the diverse and multifaceted viewpoints of stakeholders, a mixed-methods approach was employed, combining surveys with interviews and focus group discussions. The stakeholders included through Quadruple helix approach are representing academia & research institutions, civil society, policy makers and investors in the mentioned countries. The objectives of the research were to understand energy needs and priorities in different countries, assess current practices when it comes to energy modelling, facilitate collaboration between different stakeholders, and gather insights for development of energy models.
In this study participatory backcasting was refined to combine the use of existing visions in combination with stakeholder engagement and road-mapping and applied to the regional energy transition in Indonesia’s South Kalimantan Province, where the gross regional domestic product strongly depends on coal mining. Based on document analysis, interviews, consultations, and a focus group discussion, we determined necessary changes, driving factors and challenges, and co-created a roadmap towards the preferred Nett Zero Emission vision. The roadmap proposes: (1) to increase the capacity of renewable energy, particularly wind and solar, along with battery energy storage systems; (2) to transform economic activities currently based on coal towards bioenergy hubs and to build a regional economy based on renewable energy; (3) to enhance the quality of data on renewable energy potential, power grid flexibility, and variable renewable plants, and (4) to shift culture and behaviour towards energy saving, energy communities, electrification of lifestyles, and the use of renewable energy in industry. Our study contributes to the literature on participatory backcasting by a case on the clean energy transition in fossil fuel-rich nations in the Global South and advances backcasting by using existing visions instead of generating one or several new visions.
Different temporal and spatial dimensions of carbon accounting can yield varying carbon emission results. Fine-grained time- and region-specific carbon emission factor accounting for a target power grid can improve both accuracy and interpretability. This paper used a central China power grid as a case study to examine the calculation methods for carbon emission factors across different temporal and spatial dimensions. It focused on the differences in carbon accounting at substation, administrative, and voltage levels across various time periods. First, the paper summarized the development trends in power grid carbon emission factor calculations, highlighting the importance of regional division and time-based accounting. Second, a multidimensional carbon emission factor calculation method was proposed based on the coupling mechanism between power generation and carbon emissions, emphasizing the close relationship between carbon emissions and electricity under different generation structures and energy usage patterns. Finally, through quantitative analysis, the paper examined carbon emission variations across different temporal and spatial ranges and discussed the advantages and disadvantages of various partitioning strategies from the perspectives of power generation companies, electricity consumers, and the government. The study provides valuable insights for further research and standardization of carbon emission factors in power grids.
Biofuels are considered an alternative to sustainable energy production due to their potential to reduce greenhouse gas emissions. This paper presents a mixed integer linear programming (MILP) model to evaluate the optimal configuration of a supply chain for the production of bioethanol, electricity and bagasse pellets from sugarcane potential in Colombia. The results show that gasoline demand in Colombia is met through bioethanol production, and the demand for coal used in thermoelectric plants can be met through the production of bagasse pellets from 17 biorefineries located in 13 study regions. The avoided emissions represent 25.17% of the target proposed by the Colombian government, and transport emissions represent only 2.62% of the emissions generated by the model. Despite the promising results obtained in the optimization of the supply chain for bioethanol and bagasse pellet production in Colombia, there are challenges and limitations that must be considered. One of the main challenges lies in the uncertainty associated with the variability in biomass, bioethanol, and carbon credit prices, which can affect the long-term economic viability of the project. The sustainability of land use for sugarcane production must be assessed with a more detailed approach to avoid conflicts with food production and ecosystem conservation. These aspects represent key opportunities for future research and improvements in strategic planning for the bioenergy sector. Finally, the sensitivity analysis shows that the ±20% variation in the price of sugarcane and the price of bioethanol have a high impact on the payback period with respect to the base case.
Community ownership models for decentralised renewable energy (DRE) have been applied in various contexts across global south countries. However, their characteristics, effectiveness and limitations remain understudied. Understanding these ownership models is of interest in the context of bridging the persistent electricity access gap in the global south, particularly present among remote populations, and the imperative to achieve Sustainable Development Goal 7 by 2030. This study addresses this research gap through a scoping literature review and expert interviews. The findings shed light on the diverse definitions of community ownership in the context of decentralised renewables in the global south and on experiences of applying community ownership models in the global south, and identify four recurring themes: regulation, financing, roles and power, and capacities and skills. Through the lens of the multi-level perspective, we discuss the implications of our findings for energy access, socio-economic development policies and initiatives, and research.
Smart district heating systems play a major role in the sustainable energy conversation and utilization processes within energy systems by providing a novel and highly efficient way of supplying buildings with heat. This paper aims to advance the practical understanding and transformation of current use of coal cogeneration units by assessing the benefits of integrating higher efficient energy supply technologies in district heating while simultaneously modelling heat demand reduction in buildings. A bottom-up model was developed for capital city of Kosovo “Prishtina” using the referent year 2018 as a base case as the heating demand and district heating potential maps were generated for this year in previous research. Several scenarios for both district heating supply and building heat demand framed by existing and future policies were investigated. Among other the expansion of district heating system, renewable wind integration via large-scale heat pumps with thermal storage, solar thermal heating production with seasonal heat storage, changes in individual heating solutions and heat demand savings in buildings have been modelled and discussed in this article. The EnergyPLAN model was used to assess the share of primary energy supply savings for individual & district heating, electricity produced via wind turbines, while considering the synergies of sector coupling in an energy system with lowering CO2 emissions. The findings show that developed strategies for decarbonized heating and electricity sector and heat savings in buildings significantly impact the reduction in primary energy supply, renewable electricity production in an energy system with increasing flexibility and CO2 emission reduction.
This 46th volume of the International Journal of Sustainable Energy Planning and Management presents contemporary work within the diverse field of energy planning with important new contributions on local energy system transition and district heating transition – both scenario-based analyses applying the EnergyPLAN model. The volume also probes into spatial carbon emission factors for China. Moving towards implementation of energy transition measures, the volume includes work on community ownership models as well as trust and acceptance of geothermal projects in East Africa. Lastly, and novel to this journal, a final article addresses links between religious practise and energy management in Indonesian households.
