Home Energy Storage Systems (HESS) are batteries and associated electronics installed in residential buildings for the purpose of storing energy. This report explores the current status of HESS energy efficiency, identifies current standards available to test HESS energy efficiency performance, identifies current barriers to lifting the minimum energy efficiency of HESS, and makes recommendations to address these barriers.

Energy efficiency is an important performance metric for HESS because inefficient products entering the market now will have lasting impact on energy consumption for the next decade, as typical product lifetimes exceed 10 years. The International Energy Agency projects 200 GW of behind-the-meter (HESS) storage capacity globally by 2030 under a net zero scenario. Differences in HESS energy efficiency performance now could result in substantially more energy consumed by 2030 if minimum performance standards are not implemented.