Energy Institute at Haas

This study quantifies the extent to which the reported reductions in emissions from California’s electricity imports from 2011 through 2021 have been impacted by emissions leakage in the surrounding western electric grid. This evaluation looks at aggregate outcomes and does not evaluate specific transactions, imports for individual load-serving entities or compliance with regulatory provisions to minimize emissions leakage.Our empirical analysis presents two complementary estimation approaches. First, we apply marginal emissions estimation methods to quantify the amount of emissions caused by California imports each year and compare multi-year changes in our estimates of the import-driven emissions to the reduction in emissions from imports reported to CARB. Second, we apply an attributional approach to compare trends in the output of reported sources with their observed output overall. Both approaches indicate that Roughly half of the 29.6 MMT reduction in emissions from electricity imports could be construed as leakage.