South Korea's Renewable Energy Grid Bottleneck: 20-Year Capacity Gap as KDI Reports 154% Generation Growth vs. 26% Transmission Expansion

According to Korea Development Institute on July 27, South Korea's power transmission network expanded only 26% over two decades while generating capacity rose 154%, creating critical bottlenecks for renewable energy expansion. The KDI report, released by researchers Im Hee-hyun and Jeong Seong-hun, highlights that South Korea aims to deploy 100GW of cumulative renewable capacity by 2030, yet cumulative installed capacity stood at just 39.1GW as of mid-2026, requiring deployment rates four times the historical average.

The analysis reveals cost-effectiveness concerns in renewable subsidies. Cost-benefit analysis showed that excluding learning effects from accumulated capacity, solar subsidies yielded only 0.89 won in benefits per won spent, while wind power returned 0.80 won—below cost. In contrast, U.S. renewable subsidies generated 3.50 won and 5.21 won in benefits per won invested for solar and wind respectively, indicating South Korea's support programs lag in efficiency.