The survey showed that most households with a 30kWh residential energy storage system were able to maintain electricity demand during 70% of outages.
According to a study conducted by Lawrence Berkeley National Laboratory (LBNL), single-family homes equipped with residential solar systems and energy storage systems can handle multi-day power outages without shutting down critical loads such as lighting, heating and cooling impact, but this largely depends on the deployment level of the solar + energy storage system.
The study is the first in a series of reviews of solar-plus-storage systems conducted by LBNL in conjunction with the National Renewable Energy Laboratory (NREL). The report examines 10 outages over 24 hours and aims to provide a set of benchmarks for performance evaluation.
"In 7 of the 10 events, most households were able to maintain electricity using a 30kWh residential solar-plus-storage system," LBNL researchers concluded in a report published in September. "This is usually the upper limit of the size of residential energy storage systems currently on the market.
The report also points out that there may be significant differences between different household users, especially households with electric heating, which maintain electricity demand for a much lower period of time.
The researchers point out that its performance depends largely on the size of the energy storage system and the electrical load. However, if heating and cooling equipment is not considered, a small energy storage system with an energy storage capacity of only 10kWh can almost meet the power supply demand for three days.
LBNL said the study was limited because it used a variety of simplifying assumptions and did not take into account factors such as snow cover that may occur during winter events.
The report explains that snow cover is a very complex factor for residential solar installations because it depends not only on climate and physical characteristics, but also on behavioral factors. For example, whether and how often building occupants clear snow may itself depend on power outages.
It is reported that future research by LBNL and NREL may model energy efficiency and electrification measures in a wider area, including the use of heat pumps in cold climates, and the impact of battery usage other than backup power on the state of charge of solar-plus-storage systems.