Rehabilitation of a 100-Year Old Hydro Plant
The current redevelopment project is to expand the nearly 100-year old hydroelectric station from its current generating capacity of 35 MW to 60 MW. The project includes:
- expansion of the intake structure to 8,000 cfs
- construct a new power canal and steel penstock to feed the generating unit
- replacement of the existing surge pond for the generating units with new surge capabilities incorporated into the open canal
- a new powerhouse located downriver of the existing powerhouse
- one new 60 MW Kaplan turbine
- a new tailrace
- a new GSU transformer and new emergency startup power equipment
The budget for this project is nearly $200 million. The construction is anticipated to begin in early 2009. Services provided included a value planning study on the feasibility and a constructability review on the draft-final design.
Upstream Control Plant Feeding Multiple Hydropower Plants
In order to meet FERC requirements, this 100-year old intake structure is undergoing a seismic upgrade. The structure is 47 feet wide and 72 feet tall with four bays that discharge into a 12 foot diameter wood stave pipe. Each bay is isolated from the reservoir with a stoplog wall. The project was to infill the two end bays with concrete and use post-tensioned tendons to anchor the mass concrete blocks. Due to a stoplog failure and two month uncontrolled release prior to the implementation of the seismic upgrade, the first priority was to ensure there would be no subsequent failure.
Several options were being considered for both flooding and dewatering the structure, both in-the-wet and in-the-dry options. The value study identified additional alternatives using float-in and precast/prefabricated concepts that would result in a new intake structure for a 45% to 60% savings in construction cost.
New 290 MW Hydropower Facility in South America
This 282mw hydroelectric development project includes five high mountain river diversions, 33 km of 3.8 m to 4.5 m diameter tunnels, two 4 m diameter vertical shafts (450 m and 900 m), 4 m diameter steel penstocks feeding four turbine/generator units (282 MW) in a surface powerhouse. Because the tunnel diameters were being driven by constructability, not hydraulics, the value team provided recommendtaions that would allow a reduction in size. The team also suggested moving the powerhouse underground for better protection from rock falls and avalanches. By the end of the study the value team generated savings totaling over $70 million.
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