Background: In the past two centuries, energy consumption per capita has significantly increased. At the same time the fundamentals of energy provision have continuously developed towards fossil energy sources. This extended use of finite, unequally distributed and emission-intensive energy sources poses a challenge to both the energy, the climate and therefore the socio-ecological systems. Consequently, solutions are needed to reduce the fossil energy demand while fulfilling our daily energy services. District heating systems powered by renewable energy can contribute to this societal mission. Methods: This paper presents the co called Eco.District.Heat-kit, a novel planning model supporting future decision-making processes regarding grid-bound heating. The interdisciplinary approach assesses the feasibility of district heating systems at different locations from a qualitative and quantitative perspective. Given the lack of quick and simple planning tools in this field, the Eco.District.Heat-kit provides a time-efficient pre-evaluation on the basis of widely available input data. Results: The decision support model rates district heating networks regarding the thematic areas of (1) integrated spatial and energy planning (2) costs, (3) resources, and (4) environment and climate. In addition, it involves a longterm planning horizon by including spatial development and climate scenarios until 2050. Finally, the Eco.District. Heat-kit identifies parameters both positively and negatively influencing the overall rating. This enables end-users to sort out non-optimal configurations before entering a more detailed planning stage.Conclusions: Due to the straightforward methodological approach and the focus on basic parameters of district heating system planning, the Eco.District.Heat-kit supports energy suppliers, urban-planners and decision-makers at the beginning of planning processes. In order to increase both transparency and applicability of the model, its functionality and input parameters are disclosed within this paper, enabling the recreation and adaptation towards user-specific needs and local situations.

Background: District heating is widely used for thermal energy supply and offers a broad range of benefits like the possibility to integrate decentral heat supply technologies or to foster the utilisation of renewable energy sources. Thus, district heating has the potential to gradually contribute to a more sustainable thermal energy supply and to consequently facilitate the energy turn. However, due to specific requirements of this technology, strategic planning is required for the successful implementation of district heating networks. Previous research mainly focuses on either economic, environmental, or technological aspects of district heating. This study therefore aims to execute a comprehensive assessment of district heating systems in the following four sections: (1) integrated spatial and energy planning, (2) costs, (3) resources and (4) environment and climate. Methods: To this end, the recently developed Eco.District.Heat kit (EDHk) is used to evaluate and rate eight case studies consisting of 14 different urban typologies, while considering the aforementioned sections of interest. The paper applies the EDHk to assess different spatial structures and grid configurations as well as a broad mix of different thermal energy sources. Results: With regard to integrated spatial and energy planning (section 1), the assessment shows heterogenous ratings whereas the case studies exhibit quite constant positive ratings with regard to costs (2), environment and climate (4). Although a lot of material is used for the construction of networks (i.e. resources, section 3), the question whether or not to dismantle old grids for resource utilisation cannot be answered definitely. According to our results, future development scenarios in the context of climate change and building renovation until 2050 have little influence on the final ratings. Conclusions: Based on the comprehensive assessment of eight case studies, it can be concluded that district heating systems offer a long-term and sustainable solution of heat supply for different spatial archetypes and types of urban fabrics. Furthermore, the proposed methodology allows users to critically examine planned projects and to detect shortcomings at an early planning stage. The EDHk thus provides a suitable methodology to support strategic decisions in integrated spatial and energy planning.

In light of global warming and the energy turn, sector coupling has gained increasing interest in recent years, from both the scientific community and politics. In the following article it is hypothesized that efficient multifaceted sector coupling solutions depend on detailed spatial and temporal characteristics of energy demand and supply. Hence, spatiotemporal modelling is used as a methodology of integrated spatial and energy planning, in order to determine favourable sector coupling strategies at the local level. A case study evaluation was carried out for both central and decentral renewable energy sources. Considering the high temporal resolutions of energy demand and supply, the results revealed a feasible operation of a district heating network in the central areas of the case study municipalities. Additionally, building integrated solar energy technologies are capable of providing large amount of excess energy that could serve other demand sectors, such as the mobility sector, or could be used for Power-to-X solutions. It is suggested that sector coupling strategies require spatial considerations and high temporal comparisons, in order to be reasonably integrated in spatial and urban planning.

In 2018 the European Union has recognized wastewater as a renewable energy source, particularly due to its thermal energy content. To create and further develop knowledge on the possible role that wastewater could play in the energy transition, this article pursues two objectives: 1) it presents an overview on the electric and thermal energy potentials available at the wastewater treatment plants (WWTPs) in the Central European area also taking their spatial context to adjacent settlement structures into account. 2) It introduces a small number of easy to apply criteria to (pre-)assess the suitability of WWTPs for being integrated into local energy (heat) supply concepts from an integrated perspective (considering energetic, spatial and environmental aspects). The investigations address the energy generation potentials of 3,315 WWTPs (with a treatment capacity of at least 5,000 population equivalents) in the area under survey. Analysis reveal, that notable amounts of heat ranging to almost 26 TWh/a are available. Their exploitation appears very promising, as investigations also show, that about 73% of the considered WWTPs are situated near or even within existing settlement structures implying very advantageous heat supply distances. Following the estimation of energy potentials, which is made available in the supplementary material, the presented suitability criteria can then be used to identify the most promising WWTPs in a specific regional/local context, in the investigated Central European area and beyond.

<p>In the course of the energy transition, spatial and temporal aspects of energy demand and renewable energy supply are increasingly coming to the forefront of scientific studies and political debates. In this context, the use of spatiotemporal models has been identified as a decisive methodology for integrated spatial and energy planning. However, the transformation of spatiotemporal results into concrete spatial planning instruments has not yet been sufficiently discussed. Therefore, this research aims to provide answers by using specific results of a case study in Austria. In the case study evaluation, energy demand is considered in high spatial resolution using statistic data in 250m raster cells as a basis. The results are supplemented with an assessment of high spatio-temporal solar energy potentials. Taking these results as a basis, the following questions are addressed: How can spatial and temporal evaluations of energy demand and supply support the energy transition by means of spatial planning on the local level? What measures with respect to renewable energy generation, storage and grid capacity can be derived and which effects are expected to be achieved? With respect to renewable energy provision, initial results reveal added value for the spatial delimitation of district heating supply areas. Further, building integrated solar energy generation reveals high shares of excess energy – both thermal and electric – which has to be properly used, taking into account different sectors of energy demand. As a consequence, the results of this research also offer the opportunity to reflect on the benefits of sector coupling, as well as the new organization of energy supply via energy communities.</p>