|Integrated spatial and energy planning (ISEP): Challenges always have a spatial relation, as do their solutions. Energy-related issues such as the efficient extraction, conversion, distribution, storage and use of energy as well as the choice of available technology need to be spatially coordinated. Here, the research field of “integrated spatial and energy planning” (ISEP) comes into action, dealing with the spatial dimension of energy supply and demand [39, 40]. The consideration of energy related aspects in the course of spatial planning can significantly influence the energy supply, distribution and consumption as well as the associated greenhouse gas emissions through the strategic organization and control of functions and uses in space.||
Costs: Costs play a central role in the probability of technological conversion. In the end, potential heating systems will be attractive to both investors and customers if alternative options available for heating are associated with higher costs. This requires not only the consideration of the costs of heat generation, but also the construction of the network and the heat generation facilities. Focusing on the chosen technology, it depends on both technical and spatial conditions, whether a technology can be cost-efficiently installed at one specific place.|
Those forms of energy carriers and technologies should be preferred which are regionally and/or locally available in order to reduce import costs and use potentials at hand, such as renewable energy, waste heat from sewage or industry and waste and sewage sludge incineration.
Resources: In line with the "Roadmap to a Resource Efficient Europe", EU Member States are called to remove barriers to resource efficiency. The roadmap claims to complement existing energy efficiency strategies for buildings with resource efficiency strategies that focus on a wider range of environmental impacts throughout the life cycle of buildings and infrastructure with sustainable use of materials and waste recycling .|
In the light of heating systems, resources cover all materials that are bound by both the energy grids, the production sites as well as the buildings of the energy consumers. Here, type and age of the “building” under consideration influence the amount, composition and efficiency of the used materials. Consequently, the size of power plants, the length of needed pipelines and the need for rare, valuable or harmful materials play a central role.
Environment and Climate: As briefly explained in the introduction, the energy system is a main driver of anthropogenic greenhouse gas emissions and thus the main cause of human-induced global warming [23, 42]. Regarding direct and indirect effects through carbon-dioxide-emissions, both the level of current energy consumption and, in particular, its composition plays a decisive role. The lower the energy consumption of our society, and the higher the share of renewable energy sources, the more emission-extensive and ecological compatible energy can be used.|
On European Level, the most common form of heating is the use of gas in combination with a combustion boiler at home. This has to be critically scrutinized due to high emissions per kWh. Other forms like wood boiler, heat pumps or solar heating are based on renewable energy. DH represents a special from, since the needed heat load can be provided by a broad spectrum of local available energy carriers. These include waste and sewage sludge incineration, wood waste, straw as well as the utilization of waste heat by communities or industrial sites .