Tetra Tech provided engineering, procurement, and construction services for the 17.6-megawatt Fire Island Wind Project three miles off the coast of Anchorage, Alaska. The wind turbines eliminate the need for an estimated 500 million cubic feet of natural gas each year in south-central Alaska, diversify the area’s power generation resources, and add long-term power price stability to that market.

Fire Island Wind LLC, a company of the Cook Inlet Region, Incorporated, an Alaska native Regional Corporation, understood that it would require significant support from outside companies to ensure a successful project. The island, with no dock facilities, posed logistical issues such as high winds; a cold, wet climate; steep road grades; a high potential for earthquakes; and the second largest tides in the world.

Tetra Tech was the prime contractor for constructing eleven 1.6-megawatt GE 1.6 xle wind turbines and associated facilities, such as an underground collection system, collector switchyard, operations and maintenance (O&M) building, meteorological tower, access roads, foundations, and crane pads. Tetra Tech also transported the wind turbines, construction materials, and equipment to the island by barge, posing potential delays and safety challenges. 

Tetra Tech provided in-house engineering resources for the road and turbine site grading design, foundation design, O&M building design, and the site-specific stormwater pollution prevention plan (SWPPP). This integrated approach allowed the construction team to reduce the required amount of earthwork and provide input for an effective SWPPP. Continuous collaboration and communication with the client let our team to respond to change requests and identify additional value-added measures.

Tetra Tech applied innovative work methods to complete the project on time and within budget—establishing partnerships with local suppliers and vendors, using both vibro-compaction and over-excavation methods for soil improvement, and identifying critical-path activities before mobilization to plan proactively.

Tetra Tech’s self-performed construction scope included on-site quarry setup and operation, road construction, turbine site earthwork, foundation construction, barge loading and offloading, barge landings, and turbine erection. Tetra Tech’s ability to perform this work let the project team react to record winter and spring weather conditions, control the schedule, and keep the project under budget.

The construction phase was completed in less than five months and the plant produced power earlier than planned. More than 55,000 labor hours were worked in this rugged environment with zero lost-time injuries.

Highlight

An interesting video about the project is available on Fire Island Wind LLC’s website.