The siting and resource assessment for hydropower installations in the ocean, which exploit tidal currents for the generation of electric power, as well as the analysis of environmental effects of such installations, requires detailed information on the spatial and temporal variations of tidal currents. Until now, such information has been obtained mainly from in-situ measurements and numerical simulations. We would like to promote the use of a satellite-based remote sensing technique, which will become available for operational use in the near future. A combined use of circulation models, in-situ data, and satellite data will permit dynamical analyses with unprecedented spatial and temporal coverage and resolution.