Methods for actuating a downhole device in a wellbore. An example of the method is positioning a downhole device in a wellbore, the downhole device comprising a reactive metal and a reaction-inducing fluid; wherein the reaction-inducing fluid is isolated from the reactive metal. The method further includes removing the isolation of the reactive metal such that it reacts with the reaction-inducing fluid to generate a hydrogen gas, and actuating the downhole device with the hydrogen gas.

A wireline release tool may include a casing configured to couple to a wireline and a connector configured to couple to a tool string. The casing may have a first end, a second end, and a chamber therebetween, and the connector may be detachably attached to the second end of the casing. A gas generator may be disposed in the chamber and may be capable of generating gas pressure in the chamber sufficient to overcome a pressure differential between the chamber and the external wellbore environment and to detach the connector from the casing.