District heating systems can meet the heat and domestic sanitary hot water demands of the customers with lower resource use than the conventional individual supplies. They can also facilitate the integration of renewable energy sources and more efficient pollution controls (Frederiksen and Werner 2013). Despite these environmental advantages associated with district heating, these systems and their heat supply plants have associated other environmental impacts that may become overlooked when analysing and determining the heat supply options for new district heating systems, impacts that have a relevant importance if the inherent localism of district heating is accounted. The lack of comprehensive research on these environmental impacts that analyses them beyond the greenhouse gases emissions led to the following research question:
How environmental parameters other than greenhouse gases emissions can be incorporated in the heat supply selection for new district heating systems?
Therefore, this thesis aimed to create a model, EIDH-1a, to evaluate the environmental impacts associated with district heating supply options in a European context.
The Excel-based model incorporates air quality (both global and local impacts), water quality and land use indicators with the goal to provide tools and specific information to engineers, designers and decision-makers to select the most appropriate heat supply option for new district heating schemes in the early stages of the planning and design process. The model creation was based on a literature review that helped to select the fuels, technologies, and indicators to use alongside the inclusion of content in the tool.
EIDH-1a analyses heat supply options scenarios that are formed by a heat supply plant that provides the heat to meet the base demand and a peak plant to meet the peak loads of the system. The air quality indicators are determined by a ratio against a reference scenario minimising the errors inherent with the generalisations that the model encompasses. The water and land impacts are rated according the bibliography review. All indicators are pondered by the user of the tool allowing the introduction of specific particularities and goals.
In conclusion, although EIDH-1a requires some updating and polishment, the model can add value and insight to high-level studies aiming to implement new district heating schemes.