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This statement by the Rocky Mountain Institute (RMI) defends its 2014 research on 'grid defection'—the economic viability of customers disconnecting from utilities in favor of on-site solar and battery systems—against interpretations of a subsequent study by the Rochester Institute of Technology (RIT). RMI argues that while full grid defection may currently only be economical in Hawaii, the downward trajectory of distributed energy resource (DER) costs creates a systemic risk of stranded utility assets and empowers customers to influence the pace of decarbonization and grid investment.

This executive summary by the Rocky Mountain Institute (RMI) and HOMER Energy analyzes the economic transition of residential and commercial customers from grid-only electricity to grid-connected solar-plus-battery systems. The report argues that while total grid defection is possible, the more likely scenario is a gradual shift where customers use the grid as a backup, potentially leading to significant revenue loss for utilities and stranded assets for central generation owners unless new regulatory and pricing models are adopted.

This executive summary analyzes the economic threat of 'grid defection' in the U.S., where solar-plus-battery systems allow customers to bypass utilities. The report finds that grid parity is already occurring in Hawaii and is imminent in California and New York, potentially stranding utility assets and rendering the traditional kWh-based cost recovery model obsolete.