Design and construction of an off-grid gravitational vortex hydropower plant: A case study in rural Peru

Abstract Low-head hydroelectric technology is allowing the expansion of distributed power systems into isolated regions that are difficult to connect to the grid. Such technology can provide renewable energy resources to a wider population, especially in developing countries. Here, we evaluate a 10-kW-scale gravitational vortex hydropower (GVHP) system constructed on a river in rural Peru. Detailed specifications of the design, construction, and initial testing are given, along with a basic economic evaluation. We critically compare the GVHP technology to mature low-head hydropower technologies. The GVHP technology is suitable for operation at a head as little as 1 m with a minimum flow rate of 0.5 m3/s. We demonstrated that the GVHP infrastructure could be constructed with a high level of manual labor, with materials and technologies available in a developing country. The relatively small investment cost and short payback time make it an interesting option for small rural communities where connection to the grid is not favorable, or where the simplicity of the design outweighs the need for high efficiency. Labor was the main cost (despite inexpensive labor in Peru). Considering the challenging high-torque operating conditions, power transmission from the turbine to the generator is a major limitation of this system.