Passive income: NO

Starting a home battery storage system design and installation consulting side hustle has the potential to earn passive income, but it is unlikely to be fully passive for most people. While there is a growing demand for renewable energy solutions, setting up and running this consulting business requires ongoing involvement and expertise. To reach a level of passive income, one would need to establish efficient systems for client acquisition, project management, and possibly outsourcing certain tasks. Some individuals may achieve a degree of passive income by scaling their operations and streamlining processes, but it typically requires continuous effort and monitoring. Success stories of fully passive income in this niche are more likely to be outliers rather than the norm.