Microbes break down plant nutrients to release electrons that are used to create an electrical current.
A bio-photovoltaic panel installed at the Valldaura campus of the Institute for Advanced Architecture of Catalonia (IAAC) consists of a battery that produces energy from bacteria in the soil around it.
The bacteria in the soil stay alive by feeding off the by-products of the photosynthesis of plants. The bacteria breaks down plant nutrients, releasing hydrogen protons and electrons into the soil. The electrons are extracted and put into a circuit with the use of a microbial fuel cell.
The efficiency of the system can depend on various factors that affect how the electrons are collected and transferred into the system. These factors include the type of plant, the type of soil, soil characteristics that support microbial growth, and the material and components of the battery used.
The design of the panel also considered key elements such as getting the maximum voltage, allowing the plant roots enough space to grow, and enabling optimum distribution of nutrients. These were all achieved with the help of a voronoi tessellation incorporated into the irrigation system and the overall design of the panel, which consist of 3D-printed frames of cells.
According to the developers, the prototype could be used to power an electrical device or appliance.