A wavefarm (10) comprises a multiplicity of wave energy converters, comprising linear generators (19, 20, 21) and (22) which are driven by floats immersed in the sea, (14). In normal wave conditions, all of the generators supply a land line (17) via a control unit (18). In the event of inclement conditions, one of more of the generators are switched to linear motors, and these are then powered by those generators remaining in the sea, to withdraw their floats into protective cavities (23). The process is repeated sequentially until all but the last one or few of the generators have withdrawn their floats. Finally, these last are withdrawn by connecting them to an alternate power source eg a battery, (24), again via the control unit (18).