The role of regional renewable energy integration in electricity decarbonization—A case study of Japan

Decarbonization strategies depend critically on the integration of region-specific renewable energy and social acceptance, yet their roles still need to be clarified. This study designs a regional-integrated electricity system and assesses the impact of regional decisions associated with renewable energy on cost-effective national decarbonization, using Japan as a case study owing to its active engagement in regional decarbonization. A high spatial resolution renewable electricity system model that explicitly considers all 1741 Japanese municipalities and employs a hierarchical optimization approach is developed. Based on the model, the opportunity cost of limiting renewable energy development is quantified for 30 representative municipalities. The results highlight that restrictions on municipal renewable energy can increase annual system costs by hundreds of millions of euros and national electricity costs by up to 0.4%, although it varies by region and energy source. This suggests that widespread opposition to renewables could be a significant barrier to cost-effective decarbonization. However, the impact of solar photovoltaic (PV) tends to be slight. In conclusion, investments in social acceptance of region-specific renewables can minimize opportunity losses and reduce system costs. Nonetheless, relocating the project to another region is possibly more cost-effective for solar PV.