South Korea's wasted renewable energy: Looking to China for grid solutions

South Korea's ambitious renewable energy expansion is being hampered by significant output controls, a problem also faced by China, which has since implemented strategies to mitigate the issue. In South Korea, the Honam region is seeing concentrated curtailment, posing a major obstacle to the government's 2030 target of 100 GW of renewable energy.

China, a global leader in renewable energy growth, experienced severe curtailment rates between 2015 and 2016, with wind and solar power losses reaching 17.1% and 12.6% respectively. This was largely due to a mismatch between where renewable energy was generated (western inland) and where it was consumed (eastern coastal areas), coupled with underdeveloped transmission infrastructure and a power grid historically centered on fossil fuels.

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The experience of China shows that it is possible to reduce output control while significantly expanding renewable energy.

Facing a crisis where discarded energy in four years equaled Thailand's total annual generation, China set a goal to reduce curtailment to below 5%. They achieved this through a multi-pronged approach: allowing 'generation rights trading' for coal plants, mandating minimum purchase hours for renewables in high-curtailment areas, and encouraging local governments to boost power demand. This strategy successfully lowered curtailment rates significantly by 2019.

However, China's success is not without its recent challenges. Data from early 2026 indicates a renewed surge in curtailment, with clean energy output controls reaching 26.1%. This resurgence, despite policies promoting renewables, highlights the persistent influence of fossil fuels, particularly coal, within the grid. The report suggests South Korea could learn from China's experience by incentivizing coal plant reductions, boosting demand in renewable-rich areas, and exploring power-sharing mechanisms to distribute the costs of curtailment.

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In 2025, the land grid's output control volume, excluding Jeju Island, is expected to increase eightfold for solar and 52-fold for wind compared to the entire output control volume in 2024, reaching 72.3 GWh.