California’s Global Warming Solutions Act (Assembly Bill 32) requires the state to reduce aggregate greenhouse gas emissions to 1990 levels by 2020. One of the challenges California faces is how the state should regulate the electricity sector. About 80 percent of the state’s electricity consumption is generated in the state, but about 52 percent of the greenhouse gas emissions associated with electricity consumption comes from outside the state. The question addressed in this paper is where to locate the point of compliance in the electricity sector—that is, where in the supply chain linking fuel suppliers togenerators to the transmission system to retail load-serving entities should the obligation for measurement and compliance be placed. The conclusion offered is that one particular approach to regulating the electricity sector—the “first-seller approach”—would be best for California. The alternative “load-based approach” has a running head start in the policy process but would undermine an economy-wide market-based emissions trading program.