Abstract
Following the recent expansion of eligible sea areas from territorial waters to the exclusive
economic zone, Japan’s offshore wind deployment is expected to accelerate toward carbon neutrality.
Because the designation of areas for the promotion of offshore wind power requires coordination
among national and local governments and stakeholders, decision support at the planning stage is
increasingly important. This article presents a GIS-based framework for assessing offshore wind
power sites from three perspectives: social acceptability, economic viability, and ecological risk.
Social acceptability is examined using spatial indicators such as distance from shore, vessel traffic,
and fisheries activities, with threshold settings treated as stakeholder-dependent rather than fixed.
Economic performance is evaluated through site-specific generation cost estimates that reflect water
depth, distance to shore, and grid constraints, ultimately demonstrating that low-cost sites are not
always optimal from a system-wide perspective. Ecological risk to breeding seabirds is assessed using
multiple models that combine species density and sensitivity. Overall, GIS helps visualize trade-offs,
compare alternatives, and support informed and transparent spatial planning.
