Novosibirsk State Technical University (NSTU) has developed a method for generating electricity using electrokinetic phenomena. It is based on the conversion of the energy of groundwater movement through porous rocks into electricity and can be used to power geophysical equipment, sensors and equipment during field exploration.
During geological exploration, especially in hard-to-reach areas, it is not always possible to regularly use energy storage devices, which makes it necessary to have autonomous power sources. Electrokinetic phenomena can be used to generate electricity, says Evgeny Porsev, Doctor of Technical Sciences, Professor of the Department of Electrotechnical Complexes at NSTU- NETI.
One of the electrokinetic phenomena, osmo-EMF, occurs at the solid—liquid interface. When water passes through dispersed media under the influence of external pressure, it carries with it mobile ions of the diffuse layer, and part of the ions bound to the solid surface remains in place. The transfer of ions creates a spatial separation of charges and leads to a potential difference (electric voltage).
To assess the potential for extracting electricity from aquifers, it is necessary to determine the colloidal characteristics of the dispersed membrane phase (zeta potential, surface charge density) and the filtration characteristics of the soil, explains Evgeny Porsev. They determine the efficiency of converting the mechanical energy of fluid motion into electricity.
To find out the possibilities of producing electrical energy by machine-free method, scientists studied the waterlogging of loose rocks. High water availability is a basic condition for the occurrence of electrokinetic phenomena and the formation of a double electric layer.
NSTU-NETI scientists have proposed a generator circuit with which it is possible to obtain a potential difference of electrical energy due to the movement of groundwater. The circuit includes electrodes with an electrode potential and control and measuring devices. The electrodes are located in the dispersed material at various heights, which ensures the movement of water under the action of hydrostatic pressure. The development is focused on the autonomous provision of electricity to equipment in the field.