Empirical Study of Piezoelectric Energy Harvesting from Mechanical Vibrations in Nigerian Road Infrastructure

Piezoelectric energy harvesting from ambient mechanical vibrations embedded in road infrastructure offers a potential distributed micro-generation technology for powering roadside sensors and lighting in Nigeria. This study empirically characterizes the vibration energy environment at three categories of Nigerian road surfaces including federal highways, state roads, and inner-city routes in Abuja FCT, North Central Nigeria, and evaluates the power generation potential of cantilever beam piezoelectric energy harvesters optimized for the measured vibration spectra. Vibration acceleration spectra were measured at road surface, pavement subbase, and gantry sign post mounting points using MEMS accelerometers during controlled vehicle pass-by experiments and under naturalistic traffic flow. Key vibration frequency ranges and amplitude probability distributions were extracted. Piezoelectric bimorph cantilever harvesters using PZT-5A ceramic were designed with resonant frequencies tuned to dominant road vibration peaks identified in the spectrum measurements. Harvesters were physically fabricated and tested under measured road vibration profiles replicated on an electrodynamic shaker. Measured peak power output from optimally tuned harvesters reached 850 microWatts under traffic vibration conditions representative of a busy federal highway, sufficient to power wireless sensor nodes with duty-cycled communication protocols. The study develops an analytical harvester design methodology accounting for Nigerian road roughness class distributions and validates predicted output power against measured values. Impedance matching optimization and power conditioning circuit design considerations specific to low-amplitude broadband vibration environments are discussed. Keywords: piezoelectric energy harvesting, road vibration, ambient energy, Abuja, cantilever harvester