Design of a Self-Supporting Liner for the Renovation of a Headrace Tunnel at Chivor Hydropower Project

Abstract

Ensuring access to affordable, reliable, sustainable, and modern energy, as declared in the United Nations’ Agenda 2030, requires both the inclusion of new renewable energy sources, and the renovation of existing hydropower infrastructure, since this resource is considered a key strategy to support flexibility in electric grids with high penetrations of variable generation. This paper addresses the design of a self-supporting lining for the renovation of a headrace tunnel, that has been affected by a buckling event, in order to extend the operating life of the Chivor Hydropower Project, located in Colombia. Studies performed by AES Corporation about the buckling events that affected the headrace tunnel and the condition assessment are first described. Then, the design alternatives to renovate this important part of the hydropower plant’s infrastructure are presented in a general way. The detailed design and construction planning for the selected alternative are then illustrated by showing some calculations used in hydropower design. Such a renovation project is one of the first of its class in Colombia and goes from studies of the buckling events to the design of a modern lining that will be constructed while keeping the 1000-MW (6% of Colombia’s demand) hydropower plant in operation conditions, in order to extend its life for 50 more years, which represents an example for managers and practitioners of large-scale hydraulic engineering projects.