Ammonia (NH3) is an essential feedstock for modern industry and agriculture, as well as a promising energy carrier owing to its high energy density (4.3 kWh kg–1) and storage security. The electrocatalytic nitrate reduction reaction to ammonia (NRA) is a promising alternative route for convenient and distributed NH3 synthesis coupled with clean energy, and is attracting widespread attention. Building a coupled system for NH3 production between NRA and clean energy capture is an exciting direction for future distributed energy utilization and conversion. Herein, a lightweight triboelectric nanogenerators (TENGs) with ultra-low start-up wind speed (3.0 m s–1) is coupled to NRA system loaded with polycrystalline copper, enabling energy harvesting in a wide wind speed band for the efficient NH3 production. An adaptation strategy for capacitor embedded in the energy conversion process are proposed to further enhance the efficiency of coupled system, achieving a high NH3 yield of 11.48 μg cm−2 h–1 with the high catalytic activity of polycrystalline copper on cathode. This work opens up a coupled electrocatalysis and natural energy capture system for the conversion of NO3– to NH3, and provides an idea for the renewable energy conversion and nitrogen cycle remediation.