"Use" as a verb: "I use electricity." "Use" as a noun: "I make use of electricity." "Usage" is quantity used: "My electricity usage is 10,000 kilowatt hours per month." "Using" as an adjective: "My house is using a lot of electricity." "Using" as a noun: "I like using electricity."

"Use" is describing.. Example; I use the computer. "Using" Is explaining an action that is ongoing. Ex.: I am breathing. "Usage" is identifying an action that is often occurring. Ex.: My usage of my computer has increased this year.