IEC Corporation is part of a team of consultants selected by the Sacramento Municipal Utility District to provide owner's engineering services for its proposed 400MW Iowa Hill pumped-storage hydroelectric plant. The proposed Iowa Hill project will include a 6,400 acre-foot capacity upper reservoir where water would be stored. During peak electrical demand, water will flow through a 3,500-foot-long tunnel to the lower reservoir to create energy. The power generated will be distributed to SMUD customers via existing transmission lines already in place for its existing Upper American River hydroelectric project.
The pump-storage project consists of three variable speed pump-turbines in an underground powerhouse cavern. IEC is responsible for owner's engineering support on the associated Transmission/Substation package. This includes support for determining transformer space requirements, developing the switchyard location and layout, underground transmission cable/trench placement, and new transmission line re-conductoring and structures. Project work includes preliminary design, cost estimate, specifications, and recommendations for the electrical transmission system from the generator step-up (GSU) transformers to the point of connection at the existing 230kV transmission lines. Included in this scope is an 9 breaker switchyard with a breaker-and-half protection, two miles of transmission line on mono-pole towers to connect the switchyard to the existing 230kV transmission line, 230kV underground conductors from the switchyard to the GSU transformers, and specification of the GSU transformers. IEC is coordinating the switchyard project team, including various SMUD departments, to develop the project scope of work, functional description, detailed specifications, and preliminary design drawings of the electrical transmission systems for development and solicitation of the project.