Yes, the CORIS ETS has an optional internal battery pack which allows the ETS to continue to operate and locally store sensor readings for up to one month if the normal power supply is interrupted. The CORIS TH-L is battery operated and can store temperature and humidity readings internally for up to a week. The CORIS Gateway does not store readings. It can use an off-the-shelf USB battery pack to continue working if its power is lost. The CORIS Gateway and its internet connection must remain working for real-time sensor readings to be sent to the CORIS servers. Once communication with the CORIS servers is restored, all the stored readings in the CORIS sensors are automatically forwarded to the servers and permanently recorded.