Energy-Efficient City Competition

The five winning cities of the "Energy Efficient City" competition use different model-based planning tools that provide decision support in the evaluation of energy efficiency measures and greenhouse gas reduction strategies. This includes models for balancing energy flows and greenhouse gas emissions as well as simulating and optimizing energy system models.

The Institute of Industrial Management and Industrial Production has set itself the goal, within the framework of the accompanying research for the "Competition Energy Efficient City", to characterize the various modeling approaches in a comprehensive way, to analyze their transferability to other urban energy systems, and to overcome the identified obstacles to transferability within the framework of its own model development.

In a first step, the selected model approaches were characterized and integrated into the existing research landscape. It was found that a large number of models are being developed in the competing cities that are suitable for investigating different issues, from the evaluation of individual measures to the overall system design. In addition, the models differ in the type of methodology used, the temporal and spatial resolution, as well as in the choice of sectors depicted.

The evaluation of the transferability took into account, among other things, the concrete framework conditions of the respective city, such as the geographical location or economic structural and socio-economic data. In addition to the basic possibility of a transferability of the approach, however, the respective effort that would be necessary for this was also taken into account. It was found that the availability of the required input data for the application of the models in another city can be a major obstacle. In many cases, data was used that could not be collected in other cities for reasons of data protection or the effort required to collect data, or that could not be provided by third parties for competitive reasons.

In order to counter this obstacle, own methods were subsequently developed, which particularly address transferability. First, a method was developed to estimate the technical potential for the use of photovoltaics on residential buildings, which is based solely on freely available statistical data and can therefore be applied to all cities and municipalities in Germany. This method was subsequently refined so that the climatic conditions of the region under investigation are now taken into account in detail and statements can be made down to the level of individual buildings. In addition, methods for determining the potential of wind power and biomass were developed, which are also based on freely available data and can therefore be easily applied to any city or municipality.

In order to be able to derive useful recommendations for decision makers, a mixed-integer linear optimization model was developed, which minimizes the total system costs of the urban energy system under consideration of technical and user-specific constraints. This makes it possible, for example, to determine the optimal use of different technologies to achieve specific emission reduction targets. In the further course of the project, the model is to be tested in several cities and the experience gained is to be documented.

The result of the accompanying research activities of the IIP is thus a transferable planning tool for municipal decision-makers to evaluate measures to increase energy efficiency and reduce greenhouse gas emissions in cities.



Fehrenbach, D.; Merkel, E.; McKenna, R.; Karl, U.; Fichtner, W. (2013): Eine modellgestützte Analyse energieeffizienter Wärme- und Elektrizitätsversorgung in deutschen Wohngebäuden. In: M.K. Koch und H.-J. Wagner (Hg.): Wettbewerb "Energieeffiziente Stadt". Band 1: Gebäude und Haushalte, Berlin: LIT (Energie und Nachhaltigkeit, 14), S. 157–168.


    McKenna, Russell; Merkel, Erik; Mainzer, Kai; Seitz, Kilian; Fichtner, Wolf (2013): Energy in buildings. selected research in renewable energy and energy efficiency. Jahrestagung Energiewende – zwischen Konzept und Umsetzung. EA European Academy of Technology and Innovation Assessment GmbH. Wissenschaftszentrum Bonn, 03.06.2013.



    Mainzer, Kai; Fath, Karoline; McKenna, Russel; Fichtner, Wolf (2014): Ermittlung technischer Potenziale für die Photovoltaik-Nutzung auf Dachflächen von deutschen Wohngebäuden. In: Marco K. Koch und Jürgen Görres (Hg.): Wettbewerb "Energieeffiziente Stadt". Energieversorgung, Energiebilanzierung und Monitoring. Band 2: Energieversorgung, Energiebilanzierung und Monitoring. Berlin: LIT (Energie und Nachhaltigkeit, 15).


    Mainzer, Kai; Fath, Karoline; McKenna, Russell; Stengel, Julian; Fichtner, Wolf; Schultmann, Frank (2014): A high-resolution determination of the technical potential for residential-roof-mounted photovoltaic systems in Germany. In: Solar Energy 105, S. 715–731. DOI: 10.1016/j.solener.2014.04.015.



    Mainzer, Kai; McKenna, Russell; Fichtner, Wolf (2014): Modelle und Methoden zur Entscheidungsunterstützung bei der Planung urbaner Energiesysteme. In: Marco K. Koch und Russell McKenna (Hg.): Wettbewerb "Energieeffiziente Stadt". Modelle und Methoden. Band 3: Modelle und Methoden. Berlin: LIT (Energie und Nachhaltigkeit, 16).


    Killinger, Sven; Mainzer, Kai; McKenna, Russell; Kreifels, Niklas; Fichtner, Wolf (2015): A regional optimisation of renewable energy supply from wind and photovoltaics with respect to three key energy-political objectives. In Energy. DOI: 10.1016/



    Mainzer, Kai; McKenna, Russell; Fichtner, Wolf (2015): Integrating residential energy efficiency measures into optimizing urban energy system models. eceee 2015 Summer Study on energy efficiency. Chair of Energy Economics, Karlsruhe Institute of Technology (KIT). Presqu'île de Giens, 6/5/2015. Available online at


    Mainzer, Kai; McKenna, Russell; Fichtner, Wolf (2015): Rolling Horizon Planning Methods in Long-Term Energy System Analysis MILP Models. CORS/INFORMS International Meeting 2015. Institute for Operations Research and the Management Sciences (INFORMS). Montréal, 17.06.2015.



    Mainzer, Kai; McKenna, Russell; Fichtner, Wolf: Charakterisierung der verwendeten Modellansätze im Wettbewerb Energieeffiziente Stadt. In: Working paper series in production and energy.


    Babrowski, S.; Ensslen, A.; Jochem, P.; Fichtner, W. (2015): Akzeptanz von Elektrofahrzeugen im urbanen Raum. In: M.K. Koch, V. Krüger und J.A. Schmidt (Hg.): Wettbewerb "Energieeffiziente Stadt". Band 4: Stadtentwicklung und Mobilität, Berlin: LIT (Energie und Nachhaltigkeit, 18), S. 147–156.


    Babrowski, S.; Jochem, J.; Fichtner, W. (2015): Elektrofahrzeuge und das städtische Energiesystem. In: M.K. Koch, V. Krüger und J.A Schmidt (Hg.): Wettbewerb "Energieeffiziente Stadt". Band 4: Stadtentwicklung und Mobilität, Berlin: LIT (Energie und Nachhaltigkeit, 18), S. 137–146.


    Mainzer, Kai; McKenna, Russell; Fichtner, Wolf (2015): Städtische Energiesystemanalyse unter Verwendung öffentlich zugänglicher Daten. Karlsruhe (Workshop „Urbane Energiesystemmodelle“).