District Heating Sector Research Articles

Should end-users take their clothes off inside on a cold winter's day? Sustainability pressures on district heating professionals in Denmark

This research explores how district heating (DH) sector professionals /employees experience the low-carbon energy transitions-related change processes in the Danish heat supply sector. Enquiry draws upon mixed data collected among DH employees from 148 utilities. Geels’ triple embeddedness framework conceptualizes the connections between regime-level actor experiences of niche- and landscape-level pressures, sustainability imperatives, and the associated change processes. This neo-institutionalist perspective finds that the historically stable DH regime-level institutions are being destabilised. It also reveals the tensions and change inertia associated with, for example, sunk costs, infrastructural path dependencies, and professional culture. For the DH professionals, and regime-level actors, these destabilization processes challenge what were previously core regime-level professional practices, skills and taken-for-granted standards for a job well done. Indeed, professional identity and pride may be at stake. Paradoxically, the identified DH sector norms for stable, affordable, and invisible heat supply service provision may not necessarily motivate DH end-users /customers towards more sustainable heat-use behaviours: DH end-users in Denmark have come to expect these DH community heat supply provision as taken-for-granted societal goods, and the topics of space heating and thermal comfort are increasingly dissociated from consumption-related debates within public, and political realms. This DH case study shows how landscape, regime, and actor-level socio-technical trajectories interact, and it exemplifies actor-structure relationships in situations of regime stress. Perhaps it proves an exemplary case for exploring the lock-in mechanisms, inertia, restraints, and potentials of change-processes within also other societal domains and institutional realms.

Seasonal thermal energy storage employing solar heat: A case study of Heilongjiang, China, exploring the transition to clean heating and renewable power integration

Seasonal thermal energy storage (STES) offers an attractive option for decarbonizing heating in the built environment to promote renewable energy and reduce CO2 emissions. A literature review revealed knowledge gaps in evaluating the technical feasibility of replacing district heating (DH) with STES in densely populated areas and its impact on costs, fossil fuel consumption, CO2 emission reduction, and renewable power integration. The effects of large-scale STES applications on the power and DH sectors in a regional energy system were quantified by applying the 2030 and 2050 power structure scenarios. The results indicated that STES reduces fossil fuel consumption and CO2 emissions at an affordable cost. It facilitates the integration of wind and solar power into power grids. With 100 % replacement of DH by STES, fossil fuel consumption and CO2 emissions can be reduced by approximately 40 % and 45 % in 2030 and 2050, respectively, with an annual cost increase of 20 %. The CO2 avoidance costs were predicted to be approximately 60 €/t in 2030 and well below 50 €/t in 2050. STES will reduce renewable power curtailment by 10 % in 2030 and 18 % in 2050. This study investigated STES from an energy-system perspective, supporting the formulation of clean heating transition policies.

Nuclear engineering and design nuclear heat supply system for a small district heating reactor

Small Modular Reactors (SMRs) are currently considered to be a potential solution for decarbonizing the district heating sector. The LUT Heat Experimental Reactor (LUTHER) is a concept for a small modular nuclear heating plant that is being designed to meet the demands of Nordic district heating networks while also incorporating high safety standards. This paper presents an extension of the work pursued by LUT University by proposing a reactor module that allows for easy scaling of unit sizes ranging from 2 MW to 120 MW. The pressure tube assembly geometry, which has been developed specifically for the LUTHER reactor module, was analyzed by modeling two significantly different-sized variants that utilize this unique structure. The modular design of LUTHER enables complete factory-assembly and the use of standard road transport for unit sizes up to 120 MW. This design prioritizes high inherent safety, targeting for siting near population centers. The proposed heating reactor concept offers a viable means of decarbonizing the district heating sector by replacing existing combustion-based production with emissions-free nuclear heat.

Numerical study on the influence of plugging rate on the performance of adjustable steam ejector

During the operation of thermal power plant systems, severe challenges to the quality and safety of the heat supply arise owing to the effects of peak regulation. Steam ejectors, widely employed in the district heating sector, often exhibit poorer performance under off-design conditions as a result of their fixed structure. This study analyzes the effects of varying plugging rate, primary pressure, and induced pressure on the performance of adjustable steam ejectors. As the plugging rate increases, the mass flow rate of the primary fluid decrease, potentially falling below 32%, and that of the induced fluid initially experiences a minor increase, followed by a rapid decrease. Concurrently, the critical back pressure also decreases with an increase in the plugging rate, potentially falling by up to 65%. By contrast, the entrainment ratio surges with increasing plugging rate, with the maximum increase reaching up to 4.75 times. Under the same primary steam pressure and induced steam pressure, there exists an optimal entrainment ratio. Furthermore, both the critical back pressure and the optimal entrainment ratio increase as the primary steam pressure and induced steam pressure increase.

Development Forecast for the District Heating Sector to 2030

Development Forecast for the District Heating Sector to 2030

A New Method for the Techno-Economic Analysis and the Identification of Expansion Strategies of Neutral-Temperature District Heating and Cooling Systems

Neutral-temperature district heating and cooling (NT-DHC) is a recent concept in the district heating sector. The current literature does not directly address the ability to create comprehensive master plans for NT-DHC systems and reliably model their performance. This research presents a new approach for the evaluation and planning of NT-DHC systems. The methodology involves the use of a knapsack optimization algorithm to perform a comprehensive analysis of the conditions that make the NT-DHC solution competitive against individual heating and cooling technologies. The algorithm determines the optimal combination of potential extensions that maximizes overall economic value. The results of a case study, which was conducted in Italy, show that NT-DHC is more suitable in dense urban areas, while air-to-water heat pumps are better suited for low heat density zones. This methodology aims to reduce the risks associated with energy demand and provide more certainty about which areas a network can expand into to be competitive. It is targeted at energy planners, utilities experts, energy engineers, and district heating experts who require assistance and guidance in the planning and early stages of designing a NT-DHC system. This method might enable pre-feasibility studies and preliminary design to determine the opportunities and limitations of a system of this kind from an economic and technological perspective.

Modelling carbon emissions from the urban district heating sector based on system dynamics

Modelling carbon emissions from the urban district heating sector based on system dynamics

Dynamic simulation and experimental validation of a 35 MW heat pump based on a transcritical CO2 cycle

Replacing the baseload providers on the energy market with decarbonized renewable solutions increases frequency dynamics on the grid. In order to handle the concomitant risks and chances linked with this change of paradigm between energy producers and consumers, complex dynamic models are required to optimize energy management strategies. Industrial transcritical carbon dioxide (CO2) heat pumps, such as the one developed by MAN Energy Solutions Schweiz AG (MAN ES), offer a proven solution for the decarbonization of the district heating sector. Furthermore, they are associated with pathways to increase the usage of this solution for sector coupling applications. This work presents a detailed Modelica model of the high-temperature CO2 heat pump, focusing on the thermodynamic states of the refrigerant during load variations of the system. In a consecutive step, the model is validated against testbed data of a heat pump from MAN ES with over 35 MW heat supply and a lift from 40 to 100 K. The model results match the testbed data with an accuracy of over 95 % and demonstrate a full coverage of the performance map minimum to maximum speed, providing water-side supply temperatures of 50–109 °C. Realistic dynamics in fast load balancing operation are demonstrated where power consumption was varied by 80 % compared to maximum power within 30 s. Models of this kind are essential for an accurate prediction how decarbonized energy networks react by linking electricity and heat supply together. These predictions are ultimately useful to upgrade or optimize complex control strategies.

Battery energy storage utilization in optimization of heat production in district heating sector

Battery energy storage utilization in optimization of heat production in district heating sector

INTEGRATION OF HEATING SYSTEM OPERATION

Ukraine has a huge asset in the form of existing district heating (DH) networks and demand for related services. DH is transforming the European energy sector, attracting efficient, local and renewable energy resources where this was not possible. However, due to the old material base of spare parts, insufficient level of investment and low level of management, Ukrainian DH systems are ineffective and do not meet the needs of consumers. The experience of European Union member states in central Europe shows that deep and sustained reforms can address the current challenges of the heating sector, including improving energy efficiency and economic competitiveness, strengthening environmental sustainability and enhancing energy security. The DH sector in Ukraine has not yet undergone the structural reform that other sectors of the economy have already gone through: over the past 30 years, the quality of services has decreased; subsidies have increased; the old material base is falling apart; The question arises whether it is worth continuing to support DH. As a result, Ukraine's DH sector is in dire straits, with financial, operational and technical problems compounding each other. Comprehensive and well-planned efforts must be made to create the conditions for exiting this state. Such structural reforms are essential to attracting the investment needed to improve the quality, efficiency and long-term potential of the district heating sector.
 The article examines the possibility of using modern technological solutions to modernize heat supply systems in order to improve their efficiency, which can lead to improved district heating services, transparency and financial stability.
 Keywords: energy resources, renewable energy sources, fossil fuels, automated heat and power plant, electricity, hot water, hot air, heating, private households, electric water heater, geothermal heat pump, wind power generator, low-power boiler house.

Technical and economic analysis of a multicarrier building energy hub concept with heating loads at different temperature levels

Integration of renewable and waste energy sources, decentralisation, electrification and energy storage, are key pillars of energy transition in the district heating sector. Such a strategy can be implemented at the building level using the multi-carrier energy hub concept, which has recently gained popularity. This paper presents a technical and financial feasibility study of a building-integrated multi-carrier energy hub concept. The case study is performed for an existing large medical centre, where demand occurs simultaneously for electricity, cold, and heat at different temperature levels, including hot process water and steam. The central idea is to replace the high-exergy steam with heat from the municipal district heating network. The concept also includes the integration of heating and cooling loads, heat storage and implementation of an on-site photovoltaic (PV) power plant. The key components of the proposed hub technological structure are high-temperature heat pumps. Five alternative structures of the system configuration are examined using an hour-by-hour annual simulation. The results reveal that the proposed multi-carrier energy hub is fully operational. The project is also profitable, which results mainly from significant energy savings compared to the existing heat supply system using high-pressure steam. However, the profitability strongly depends on the system configuration, and the choice of the best option is ambiguous. The system with heat storage reaches the highest net present value (NPV) while the one without the storage results in the highest internal rate of return (IRR) due to significantly lower capital expenditures (CAPEX). In all cases, the project leads to a considerable cumulative CO2 emissions reduction, which is at the level of 1351 up to 2961 tons annually depending on system configuration.

Business Model Innovation for Digitalization in the Swedish District Heating Sector

Despite decades of research and development, digitalization remains a key challenge for the Swedish district heating sector. Business model innovation is believed to be necessary to capitalize on digitalization, yet it is especially challenging for municipal companies. This study aims to identify the potential impact of digitalization on the business models of Swedish district heating companies and to analyze the barriers that exist for digital business model innovation. Through case studies of eight municipal district heating companies, this study demonstrates how the entire business model is potentially impacted by digitalization. This study also identifies the barriers to digital business model innovation that are linked to two conflicting views (restrictive versus comprehensive) on digitalization. The restrictive view diminishes the importance of business model innovation, outsourcing innovation to minimize both costs and risks for the company. In contrast, the comprehensive view embraces digital business model innovation through trial-and-error and opens the innovation process to stakeholder influence. These two perspectives are motivated by different beliefs about the need for digitalization to secure future business opportunities, as well as differences in owners’ risk appetite. The implications for industry outlooks and the design of policy support for the digitalization of district heating are discussed.

Design and Development of a Conceptual Solar Energy Laboratory for District Heating Applications

The decarbonization of the district heating (DH) sector is receiving attention worldwide. Solar energy and heat pump technologies are widely considered in existing and new DH networks. There is a need to understand the influence of solar energy on district heating experimentally. However, only a few university laboratories are focused on district heating aspects. Further, the concept of such laboratories is not adequately disseminated in the scientific literature. The main objective of this paper is to develop a conceptual design of a solar energy laboratory with a focus on district heating systems. The proposed concept forms part of the preliminary study carried out by a research group at the Tallinn University of Technology. First, a brief literature review on solar energy laboratory development is provided. Then, the conceptual design of such a laboratory is presented, along with a case study. Regardless of project size, the main components of a district heating-based solar energy laboratory are solar collectors, thermal energy storage (TES) tanks, and a control system. The proposed laboratory is expected to serve multiple roles, such as a practical laboratory to provide interdisciplinary courses for students, a research and experimental platform for researchers, and a cradle to achieve the campus green initiative. It is roughly estimated that the thermal energy output from the proposed laboratory would meet around 25% of the heat demand of the institutional building during the summer season (May, June, July, and August). It is expected that the present study will be a reference material for the development of innovative energy laboratories in educational institutions.

Why go public? Public configurations and the supportive and divergent views towards public district heating in the Netherlands

IntroductionCities are taking up services of social importance under the (re)municipalisation movement. The Dutch government embarked on an ambitious heat transition and proposed in 2022 to make all district heating projects public or semi-public, with a majority public share. This proposal has sparked intense debates among groups in favour of and against a shift to public ownership.MethodsThis study assessed 16 public projects through qualitative research and uncovered the arguments for and against public ownership among key public and private stakeholders.ResultsWhile public ownership is deemed necessary to meet social objectives and address the shortcomings of private models, critical views question the economic performance and inappropriate political choices in some public projects. These critical views propose alternative ways to safeguard public values, such as ensuring affordability and meeting climate goals. Despite disagreements, public and private actors recognise the shared responsibility and the importance of the other's role. They agree that the central government's proposed mandate for public ownership may limit flexibility at the local level and prevent other effective configurations like public-private partnerships with equal public-private shares.DiscussionReflecting on the study findings, it is debatable whether mandating public ownership nationwide, as proposed by the Dutch government, should become the approach to tackle current challenges instead of allowing more flexibility. The upcoming Heat Act may reduce key issues justifying public ownership, such as affordability, cherry-picking and the lack of transparency of private projects. Further research is needed to determine whether public ownership would enhance citizens' support and speed up realisation. Public ownership may still be necessary if social and cost benefits outweigh those from other configurations or long-term concession contracts are too risky. Implementing regulations protecting public values and enabling the coexistence of public, private or public-private configurations tailored to each unique local context could be an alternative, as successful district heating sectors abroad demonstrate.

Smart heat tariffs in transition to free market

Innovative pricing mechanisms should motivate heat suppliers and consumers to move toward more sustainable energy systems and introduce low-temperature district heating systems and sector coupling in smart energy systems. Therefore, district heating regulation regimes should also be changed to stimulate transformations in the energy sector. The district heating tariffs depend on many factors, including fuel prices, operational parameters, taxes, investments, and other criteria. Therefore, an analysis of the DH tariffs has been implemented to find solutions to motivate DH enterprises towards energy efficiency and climate neutrality. The analysis results are based on the decision-making assessment approach by selecting various criteria and evaluating them from five significant aspects: engineering, environmental, climate, economic and socioeconomic. The central elements within the developed fuzzy cognitive mapping model are investment costs, heat production costs, and primary energy consumption. Considering the set boundary conditions, the most beneficial method for smart heat tariff definition could be heat tariff benchmarking with integrated energy efficiency standards for DH operators.

Energy transition for the rich and energy poverty for the rest? Mapping and explaining district heating transition, energy poverty, and vulnerability in Czechia

This paper considers the planned transformation of the district heating sector as an opportunity to protect households from energy poverty, while also acknowledging the potential for increased susceptibility. We aim to contribute to energy vulnerability research through a two/phased sequential explanatory research design, which is uncommon in energy poverty research. In the first stage, we develop an index to reveal the detailed socio-spatial distribution of urban energy vulnerability in Czechia. This index can be used as a primary tool for targeted regional and local policies. In the second stage, we confirm the validity and disaggregation of the index through local research. In addition, this process uncovers vulnerabilities not captured by the index or that add meaning and depth to known vulnerability factors. We identify multiple pathways of energy vulnerability stemming from socioeconomic and material-technical factors, as well as combinations thereof. Our research shows that urban energy vulnerability is rooted at different levels, ranging from the household to the state, and is influenced both by past deregulation/liberalisation efforts and rising energy prices, which can jeopardize planned projects. Our analysis highlights the crucial role of district heating systems in urban energy vulnerability, their socio-economic fragility, and their inherently political nature.

Solar Photovoltaics in District Heating and Cooling Sector: An Overview

With the prevalent energy scenario and climate changes, decarbonising energy sector has become the need of the hour. An environmentally friendly way is the utilisation of solar energy, which mainly involves the deployment of photovoltaic (PV) panels and/or solar thermal collectors. Unlike electricity generation, the application of photovoltaics in the district heating & cooling (DHC) sector is relatively new. Also, this energy route is not fully explored by scientific community. This paper aims to provide an overview of the photovoltaic application in district heating & cooling sector. At first, the utilisation of solar energy in the DHC sector is briefly described. Then relevant literature in PVDHC is reviewed. It was understood that different topologies are in place for solar energy integration in the DHC system. These topologies vary in terms of the chosen technology, energy storage, system configuration (centralized/distributed) and components. It was found that the research database on the studied topic needs enhancement, with a special focus on PV cooling. From the literature survey, it is deduced that solar PV could play a significant role in future DHC systems due to the possible combination with other energy sources or electric grid or storage technology. Based on the SWOT analysis, it is concluded that there is an enormous opportunity for PV integration in the DHC sector. However, adequate techno-economic support is required to overcome threats and weaknesses. This study is expected to be beneficial to policymakers, researchers and other stakeholders in district energy market.

Impacts of earlier natural gas phase-out & heat-saving policies on district heating and the energy system

Decarbonizing the district heating sector is essential for an affordable energy transition. Decarbonization strategies focusing on the interaction between power sector, individual heating technologies, heat-saving measures, and district heating expansion are missing in literature. We use energy system investment optimization to analyse the impact of decarbonization policies on district heating by comprehensively modelling the above-mentioned interaction across power and heating sector, and within the heating sector. We model decarbonization policy scenarios of massive investment into heat-saving measures and an earlier natural gas phase-out by 2030. Using Denmark as a case study, we identify policy-driven investments into heat-saving measures as non-optimal. Our results indicate that district heating expansion facilitates an earlier natural gas phase-out, which is a viable policy that inflicts only 0.07% extra system cost compared to a scenario with only net-zero emission targets. Furthermore, we find that decarbonized district heating sector has a very high reliance on industrial excess heat, biofuels, and electrification. A biomass tax reduces the high utilization of raw biomass and promotes its more sustainable use in carbon capture and storage. Our results show a cogeneration capacity reduction, which poses a challenge to the business model of conventional Danish district heating companies.

The problem of modeling the heating sector at the city level

The article proposes a model for the functioning of the district heating sector. However, at the city level, a number of problems arise: problems of modeling the heat supply of cities associated with the inconsistency of statistics on the production and supply of thermal energy - unequal estimates of heat supply, losses and specific fuel consumption; the problem of forecasting heat consumption in cities; the problem of modeling the financial balance of the DH sector in cities. These problems can lead to an erroneous description of urban heating systems and the possible adoption of incorrect decisions on the development of the city's district heating, which has an impact on the development of the country's industry.

A Brief History of District Heating and Combined Heat and Power in Denmark: Promoting Energy Efficiency, Fuel Diversification, and Energy Flexibility

The World Energy Council ranks the Danish energy system among best in the world judging by the energy trilemma criteria: energy security, energy equity, and sustainability. District heating (DH) and CHPs are pivotal for this ranking. This brief historical account illustrates how a mix of historical events, collective societal experiences, cultural and political values inform the Danish history of DH and CHPs. After the global energy crisis in the 1970s, public and political sentiment called for energy independence, alternatives to imported fuels, and alternatives to nuclear power. National-scale collective heat infrastructure planning initiatives targeted the energy policy objectives: energy independence, fuel diversification, and energy efficiency, and a political culture of broad coalition agreements made the necessary long-term planning possible. In the following decades, growing environmental awareness and concern called for renewable energy resources as alternatives to fossil fuels. Research considered the role of collective memories and temporal distance (i.e., time) for this sociotechnical journey; it notes the innovative thinking, re-use/re-cycling and energy efficiency focus that still characterize the Danish DH communities today, and it suggests that the intangible, yet reliable nature of heat could lead to the rebound effect in end-user heat-consumption behaviours. The methodological question of how, and to what extent, historical insights and lessons learnt may be translated across contexts is raised and discussed. Although sociotechnical trajectories may have granted the Danish energy system a head-start in the global race towards low-carbon energy transitions, perhaps the route was less direct than popularly portrayed. The Danish DH sector currently faces challenges of growing biomass import dependency, but also the potentials of sector coupling and energy flexibility. Energy efficiency and energy flexibility potential may be harvested via DH and district cooling solutions in future ‘smart’ energy systems globally. Hopefully, insights and lessons learnt from this brief history of Danish DH and CHPs prove informative elsewhere.