Competition and synergy between energy technologies in municipal energy systems

The dynamic energy optimization model deeco is a tool for analyzing competition and synergy between different technologies of the rational use of energy and for utilizing renewable energies. For given time series of the fluctuating heat and electricity demand, deeco calculates the optimal combination of energy-conversion technologies while taking into account local parameters like ambient temperature and insolation. Thus, the model provides a flexible instrument which may support investment decisions when building or restructing municipal energy systems. As an example, deeco was applied to a model city called Würzburg which is based on a real city of the same name located in southern Germany. Gas-fired, medium-size cogeneration units are found to be the best solution (30% primary energy and 2% cost savings) in a cost-benefit comparison with a system providing heat from conventional oil-fired boilers and receiving electricity from the inter-regional public grid. The influence of energy taxes on relative costs of different technologies is analyzed.