Variable-speed microhydropower energy systems have recently received significant attention in the renewable energy field, due to its overall efficiency and great potential available worldwide. This emergent technology combined with maximum power point tracking (MPPT) techniques allows us to replace the burden classical governing mechanical systems, being a very effective way of ensuring high energy efficiency when operating in free water flows. In this paper, a variable-speed microhydropower plant based on a semi-Kaplan turbine is employed and a novel adaptive high-performance MPPT technique is proposed. This allows high tracking quality due to superior dynamic response and high output power quality due to steady-state oscillations cancellation. This approach has been experimentally validated by using a dedicated test rig.