Optimizing Micro Renewable Generation for Smart Cities by Combining Solar and Geothermal Energy Potentials - A Case Study of the Hannover Region Topics: Integrating Renewable Energy Sources into the Smart Cities Grid; Microgeneration; Planning and Design Challenges for Smart Cities In Proceedings of the 3rd International Conference on Smart Grids and Green IT Systems SMARTGREENS - Volume 1, 283-288, 2014 , Barcelona, Spain