2012 – spring Issue

Geothermal "" A First for Interstates

When Interstates was awarded the electrical construction package for the Hudson Ranch I geothermal power plant in California, it marked the beginning of a new chapter in Interstates company history. Hudson Ranch I is the first geothermal power plant project for Interstates. Our teams are working with Performance Mechanical Contractors and AMEC to construct the facility.

Hudson Ranch I is a 49.9MW high temperature flash geothermal power plant located north of Calipatria, CA and southeast of the Salton Sea. Hudson Ranch I is the first power plant constructed to use flash technology in 20 years. Flash technology involves pulling deep, high-pressure hot water into lower-pressure tanks and using the resulting flashed steam to drive turbines that produce electricity. This type of system requires water at fluid temperatures of at least 180 degrees Celsius, usually more.

Electrically, the project includes installation of approximately 200 motors (the largest being 2500Hp); 1400 devices; and 175 lights.

Early in the project, AMEC provided Interstates with a 3D model to aid planning. Teams used the 3D model to virtually construct cable tray brackets, motor conduits, and control conduits within the model. The process involved sketching out parts of the project, such as the motor conduit, and then incorporating items into the 3D model. With information in the model, the software was used to create an isometric drawing for each conduit, which was then shared with InterFab for prefabrication. Use of 3D modeling allowed for nearly 90% of the necessary motor conduit to be shipped directly to the site ready for installation. Teams were able to complete the layout of approximately 34 control junction boxes and 150, two-inch conduits that are routed out of these boxes. Additionally, teams used 3D modeling to design roughly 400 brackets for the 8,500 feet of multilayered galvanized steel cable tray that was installed.

A company's first project for a new industry is certain to pose unique challenges. However, the site location itself posed the greatest challenges. The remote location made coordinating material, equipment, and partners a key success factor. Project leaders made the early strategic decision to include an on-site representative from our material supplier which proved invaluable. Like all projects, schedule was a big concern. Constant planning throughout the project, prefabrication, and hard work allowed Interstates to accomplish this project.

Interstates' construction portion of the project wrapped up in January 2012. Team members continue to be on site providing startup support and assistance as the facility works through its testing phase and is being brought online. Hudson Ranch I is expected to be online in the Spring 2012.