A variable electrical generator (20) is operable to convert mechanical motion to electrical power. The generator (20) includes at least a stator element (60) and a rotor element (50) including coils (320) and magnets (90). The generator (20) includes a configuration of modules (80) including the coils (320) for generating wavelets (30) in response to the coils (320) interacting magnetically with the magnets (90), and a control arrangement (70) for combining the wavelets (30) for generating a composite synthesized power output (10) from the generator (20). A method of maintaining a variable generator (20) includes steps of: (a) determining operating status of modules (80) of the generator (20); (b) unplugging and replacing one or more defective modules (80) as identified in step (a). The generator (20) is susceptible to being used in renewable energy system, for example in a tidal water turbine, in a wind turbine, in association with an oscillating wind vane, in association with an ocean float, in a hydroelectric turbine, in a steam turbine.