North Korea appears to have taken the first step toward constructing a long-planned tidal power station that could become the world’s largest once built, according to NK Pro analysis of satellite imagery, weeks after leader Kim Jong Un said such a project could help solve “power shortages.”

Planet Labs imagery shows construction crews started building a new embankment in late January across Haeju Bay, located on the southwest coast near the inter-Korean maritime border.

The project appears to be in the early stages and has so far been limited to artificial embankment work — reaching