Piezoelectric elements for power generation and/or actuation are described. An aspect is directed to generators utilizing piezoelectric elements for electrical power generation. Such a generator can use one or more arrays of piezoelectric cantilevers for electrical power generation in conjunction with modulated air pressure used for exciting the cantilevers. The pressure level/modulation and cantilever area can be controlled variables for maximizing the bending, and hence energy generation, of the cantilevers. A further aspect is directed to hydraulic fluid actuators utilizing a pumping mechanism that includes a piezoelectric element. The linear actuators can advantageously utilize the high force and high frequency characteristics of a piezoelectric membrane in conjunction with a large stroke and actuation direction conversion afforded by hydraulic transmission.