Predictable Renewable Generation, Coal Displacement, and Energy Security

This paper examines whether large-scale tidal energy can contribute to decarbonization and energy security by reducing fossil fuel dependence and carbon dioxide (CO 2) emissions intensity. Focusing on South Korea, we exploit the full operationalization of the Sihwa Lake Tidal Power Station in 2012 as a quasi-experimental policy intervention. Using national time-series analysis, difference-indifferences estimations against Japan and a broader group of Asia-Pacific economies, and a synthetic control approach, we analyze changes in energy intensity, electricity generation by fuel type, and per-capita CO 2 emissions. The synthetic control method constructs a data-driven counterfactual for South Korea based on comparable Asia-Pacific economies, allowing us to assess post-treatment deviations in coalbased electricity generation and coal-related emissions. Across the empirical approaches, the evidence is most consistent for a reduction in coal-based electricity generation after 2012. Coal-related per-capita CO 2 emissions also decline in several specifications, although the synthetic-control placebo evidence for emissions is more suggestive than conclusive. By contrast, aggregate per-capita CO 2 emissions remain broadly stable, and evidence on overall energy intensity is more sensitive to the choice of comparison group. The estimated coal effects persist after controlling for international climate policy through a Paris Agreement indicator, indicating that South Korea's post-2012 energy transition is not fully explained by common policy shocks. Overall, the findings suggest that large-scale tidal power can support decarbonization primarily through the displacement of coal, with potential implications for energy security in highly import-dependent economies.