Allison Creek Hydroelectric Design-Build

Natural Resources
Licensing/relicensing, Alternatives analysis/feasibility study, Conceptual design, Engineering services, Final design, Environmental/permitting, Self-performed construction, Engineering during construction, Testing & commissioning
Alternative delivery, Construction, Consulting
Valdez, AK
Copper Valley Electric Association
why it matters

Copper Valley Electric Assocation (CVEA) has been plagued with high cost of fuel and while they cannot control the cost of fuel, they did take action to lessen their reliance on fuel for power generation. The Allison Creek Hydroelectric Project displaces 725,000 gallons of fuel annually, eliminates 12,000 tons of carbon dioxide annually, and allows their current Solomon Gulch Lake to store more water going into the winter generating 15 million kWhs to increase CVEA’s renewable energy portfolio from 50 to 65 percent of total generation requirements. McMillen was excited to complete the design and construction of this new asset for CVEA that has seen record annual hydro generation and an extension of the summer generation season, an additional 6-8 weeks, provide benefits for generations.

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McMillen performed a full suite of services to design and build the Allison Creek Hydroelectric project, a new 6.7 MW hydroelectric facility near Valdez, Alaska. As the prime and design-build lead, we delivered everything from site analysis, permitting, and comprehensive design and engineering to self-performed construction and commissioning. The final project included development of a new powerhouse, substation, diversion structure, penstock, and supporting infrastructure.

Initial site investigations kicked off a host of investigative and design services. We performed geologic mapping, snow avalanche hazards analysis, geophysical surveys, and subsurface investigations with helicopter-assisted drill rigs. Our team also conducted comprehensive hydrologic and hydraulic analyses to confirm operating design flows for the powerhouse, penstock hydraulics, available flow at the diversion structure, and flood flows on Allison Creek. These investigations helped us identify geologic hazards, foundation design, and other constructability issues.

Following site investigations, our team developed all civil, structural, mechanical, electrical, and hydraulic engineering plans and served as engineer-of-record. The modeling team worked alongside our in-house construction team to develop effective construction sequencing for critical events like concrete pours. The final design underwent three formal client reviews and two Federal Energy Regulatory Commission (FERC) reviews. Despite multiple review periods, the design was completed in only five months, from initial concept to final stamped drawings.

Once the design was approved, our construction team got to work excavating the powerhouse, pouring concrete for the powerhouse, tailrace, and diversion structure, and installing 7,000 feet of penstock. We developed site access roads, drilled and blasted an access tunnel, erected and built out the powerhouse, and oversaw installation of the turbine/generator equipment and overhead transmission line. Construction windows were restricted to the summer months due to weather, resulting in an accelerated schedule. An effective approach and sound sequencing plans were critical to completing the work within the available construction period.

After construction, McMillen managed all startup and commissioning. This included testing and energizing a new 4-mile-long 25 kV transmission line and main power transformer; putting powerhouse systems into service; placing a 35-ton overhead crane into service and performing subsequent load testing; balance of plant; operational testing of the new turbine and generator; initial online testing; load rejection testing; and testing of safety systems. Our team assembled operations and maintenance manuals and provided final as-built drawings for the completed project.

Throughout the project, we managed the FERC licensing process. We assembled the Pre-Application Document, navigated the Alternative Licensing Process, developed study plans, conducted natural resource studies, filed the license application and Environmental Assessment documents, and submitted associated federal, state, and local permitting applications. Following receipt of the license, our team led environmental management plans, pre-construction filings, and environmental monitoring and reporting during construction. After construction and commissioning, our team continued to perform environmental monitoring and license implementation.

We paid particular attention to environmental and fish protection measures for the entirety of the project. We developed, administered, and adhered to more than 20 environmental and wildlife protection plans. These included work plans and submittals related to the care and diversion of waters on the project site, affecting fish passage and discharges directly into populated waters. We were particularly cognizant of procedures surrounding the use of heavy equipment within 100 inches of flowing waters, conversion of equipment to bio-friendly fluids, fueling and maintenance procedures, equipment storage and drip prevention, and spill containment and notification processes.

McMillen’s team worked in close partnership with our client, Copper Valley Electric Association (CVEA), throughout the design and build process. Regular collaboration and continuous communication allowed us to develop a subcontracting plan, an equipment procurement process, and a risk management methodology to effectively and efficiently address project risks. This fully integrated partnership allowed us to deliver the Allison Creek Hydroelectric facility $10M under the initial project budget.

“In my 15 plus years of project management, this contractor is the best I have ever dealt with. They have truly been a partner in the effort. They made frequent suggestions to reduce my costs and improve quality on the project that I approved for implementation. They also assisted me in negotiating better prices for other contractors that worked on the project but were outside the scope of their main design/build contract. I wholeheartedly recommend this contractor for any contract: large or small, simple or complex, inexpensive or expensive, rushed or not rushed. In my case, the Allison Creek Hydroelectric Contract Project was built under extremely difficult terrain and harsh weather conditions. The potential for cost overruns was extremely high, yet the contractor stayed on schedule and on price throughout the contract. The company stayed involved in my project at all levels, even as high as the President. I was completely satisfied with both the Design Team and the On-Site Construction Team that built the project. If or when I have another project to build, this company will get my business again.”

John Duhamel

CEO (retired), CVEA

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