NOVELTY - The system (3) has a receiving module (30) for receiving information of power usage, characteristics of a power supplying device, characteristics of a battery, and characteristics of a power supplying network entered by a user (36). A storage module (31) stores all the received information. An evaluating module (32) e.g. CPU, calculates power consumption information by analyzing or comparing all the received information stored on the storage module, according to a preset rule or algorithm. A display module (33) displays the power consumption information for the user.    USE - System for evaluating power usage of a power supplying device such as solar panel, hydroelectric generator set, wind power generator set and fuel cell e.g. metal-air fuel cell, a battery such as primary battery and/or a secondary battery, and a power supplying network (all claimed), of a vehicle. Can also be used for lighting and industrial applications.    ADVANTAGE - The system ensures effectiveness in analyzing, evaluating and optimizing power consumption behavior of users, thus assisting users in deciding the best power consumption mode according to the calculated information about power consumption.    DETAILED DESCRIPTION - The information about power usage is basic user information, power usage demand information, environmental information and/or behavior modes of energy consumption, the information about characteristics of the battery including price, charging/discharging time, lifetime, weight and/or size, and the information about characteristics of the power supplying network including power rate, power mode, service time and/or power capacity, and the power consumption information including recommended information about the power supplying device, recommended information about battery types, recommended information about battery ratio, battery maintenance, battery capacity, and battery usage, and usage information about the power supplying network and/or package information about electric utility service plans. An INDEPENDENT CLAIM is also included for a method for evaluating power usage applicable to a power consumption environment.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of a power usage evaluating system.    Power usage evaluating system (3)    Receiving module (30)    Storage module (31)    Evaluating module (32)    Display module (33)    User (36)