Yet…this study used current battery costs (at $350/KW-Hr), ignoring probably cost decreases, and then made more restrictive assumptions about how such a system might work. It’s not clear if “defection” meant complete self sufficiency, or reducing the generation portion (which in California about half of electricity bill.) Regardless, the study shows that grid defection is cost-effective in Hawaii, confirm the RMI findings. Even so, RMI said it would take at least 10 years before such defection was cost-effective in even the high-cost states like New York and California.
A more interesting study would be to look at the “break-even” cost thresholds for solar panels and batteries to make these competitive with utility service. Then planners and decision makers could assess the likelihood of reaching those levels within a range of time periods.