The anticipated increasing use of key natural energy resources, which become extremely scarce, in the coming decades have sparked significant world-wide efforts toward the search for the cost-effective renewable and green energy sources to meet global energy demands of future. In this regard, advances in self-powered nanotechnology allowing for the design of efficient energy harvesting offers an enormous potential for the creation of sustainable systems utilizing incessantly natural ambient energy sources. In particular, recent developments in mechanical energy harvesting using piezoelectric and related materials present innovative and emerging research topics in the area of a green energy technology, providing a “battery-less” solution with time, cost, and environmental benefits. In this talk, the ability and the fascinating harvesting features will be discussed with current progress regarding advanced mechanical energy harvesting technologies and methodologies i) to increase power density, ii) to integrate into different type of energy harvesters or energy devices, and iii) to create novel and viable applications.