Solar Driven Evaporation-induced Electricity Generation from Soil: An Experimental Investigation

• Introduce soil-based photothermal materials for hydrovoltaic applications. • A record-high evaporation efficiency of 92 % and power density of 0.21 mW/m 2 . • Developed a cost-effective, scalable method by integrating activated carbon into soil. One effective approach to achieving sustainable energy solutions is the generation of power through solar evaporation-induced water flow from natural materials. This study experimentally investigates electricity generation through solar evaporation-induced water flow and soil. Firstly, a wide range of experimental analyses is conducted on soil samples from various classifications. Then, the intrinsic properties of soil, including light absorption, porosity, contact angle, permeability, and microporous channels, are measured. Among all the samples, Mashhad soil (classified as SM silty sand under the Unified Soil Classification System) showed the best performance, achieving a maximum evaporation efficiency of 83.4 % and an open-circuit voltage of 205 millivolts. To improve light absorption leading to increased evaporation rates and voltage generation, a combination of soil and activated carbon was examined. The results reveal that a 50/50 wt. ratio of soil to activated carbon increases the evaporation efficiency to 92 % and achieves a maximum power density of 0.21 mW·m −2 under 1 kW·m −2 during a closed-circuit test. These findings highlight that a soil–activated carbon composite can serve as a simple yet effective method for large-scale energy conversion from solar radiation and rainfall.