Time and spatial resolved simulation as key instrument to develop sustainable urban energy systems based on renewable energies

A growing number of cities worldwide become aware that they are key actors to tackle global challenges like climate change and energy scarcity. To support cities to become sustainable the German Fraunhofer Society on applied research formed a research network under the brand name »Morgenstadt - City of the future«. Urban energy systems are a relevant research topic since energy is very important for cities to become sustainable. The transformation of an urban energy system to a sustainable energy system based on Renewable Energy Sources (RES) needs several years at least for large cities. New technologies, equipment and infrastructure must be developed and installed for generation, conversion, storage, distribution and consumption of electricity, heat and cold, and energy sources for transport. At the beginning of the transformation, an ENERGY MASTER PLAN must be developed including the ENERGY TARGET SYSTEM and the ENERGY ROADMAP, which describes the path to achieve the ENERGY TARGET SYSTEM. A procedure to develop the ENERGY MASTER PLAN step-by-step is described. An extensive involvement of main stakeholders and strong governance structures are important to implement such a process successfully. To identify the optimal ENERGY TARGET SYSTEM the ENERGY TARGET must be set precisely. Especially the origin of the RES and the balancing period must be well defined. Based on that ENERGY SYSTEM SCENARIOS can be simulated and the TARGET ENERGY SYSTEM identified. Since the fluctuating solar energy and wind energy are usually the main RES used, temporally resolved simulations of ENERGY SYSTEM SCENARIOS are necessary. Therefore Fraunhofer ISE is developing the model »KomMod«, which allows to simulate detailed TARGET ENERGY SCENARIOS as a sound basis for decisions on the ENERGY ROADMAP. To cover the interdependencies of the components of the energy system »KomMod« includes all four demand sectors and takes a macro-economic perspective. System design and operation are optimised simultaneously and the model is provided with perfect foresight. All components are implemented with the modelling environment AMPL, following a homogenous modelling approach and building one simultaneously solved equation system.