This chapter presents the results of the investigations leading to the development and application of a general procedure for the characterization of tidal current energy resources in data-poor sites. It implements methods to identify suitable sites for tidal power extraction, estimate effective power potentials, and assess impacts of tidal turbine arrays on the environment. The process relies primarily on results from high-resolution, three-dimensional circulation models. Guidelines for the development of circulation models in data-poor sites are provided. Furthermore, a decision support system embedding the entire resource characterization procedure that has been developed to facilitate analysis and support authorities in the assessment and spatial planning of tidal turbine arrays is presented. Results of the application of the proposed procedure to the target sites selected by the Indonesian government led to the improvement of information base regarding the potential of tidal energy in Indonesia.