NOVELTY - Controlling a temperature and pressure of a cryogenic liquid methane storage unit, comprises: generating methane gas from a reservoir (412) of liquid methane stored within the methane storage unit; venting the methane gas through at least one outlet valve connected to the methane storage unit; generating electric power using the vented methane gas; and initiating a cooling cycle using the generated electric power, where the cooling cycle reduces the temperature of the reservoir of liquid methane and reduces the pressure in the methane storage unit.    USE - The method is useful for controlling a temperature and pressure of a cryogenic liquid methane storage unit.    ADVANTAGE - The method: provides intelligent, safe, scalable, self-contained, standalone, cryogenic, liquid methane storage; utilizes system, which can be left unattended with negligible risk of catastrophic failure or release of methane to the environment; provides increased storage period; and produces green energy.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a system for storing liquid methane, comprising a central hub, a first micro anaerobic digestion unit connected to the central hub and a controller (416) configured to monitor at least one pH, temperature, gas production rate and gas pressure of the first and second micro anaerobic digestion units, where the first and second micro anaerobic digestion units are each configured to produce gaseous methane according to an anaerobic digestion process, vent the gaseous methane from a methane storage unit and generate power using the vented gaseous methane; and    (2) a cryogenic liquid methane storage device comprising a methane storage unit, a methane input coupled to the methane storage unit and adapted to provide liquid or gaseous methane to the storage unit, a cooling unit (404) located at least partially within the methane storage unit, a methane output coupled to the methane storage unit and adapted to vent methane gas from the storage unit and a power generator coupled to the methane output, where power generator is configured to operate using the methane gas vented from the storage unit and provide electrical power to the cooling unit.    DESCRIPTION OF DRAWING(S) - The figure illustrates methane storage unit.    Inlet valve (402)    Cooling unit (404)    Reservoir (412)    Microcontroller (416)    Battery (420)