Delta Star Case Study: Avista

Spokane, Washington: Panoramic cityscape view of Washington Water Power building and the Monroe Street Bridge along the Spokane river, in Spokane, Washington.

About the Company

Avista is an investor-owned utility that provides energy services to customers located throughout parts of Oregon, northern Idaho, and eastern Washington. While many companies purchase energy from outside sources, Avista generates 75 percent of their own electricity, mostly through hydropower plants.

Historical Background

Post Street Substation, located on the Spokane River in Spokane, Washington, was originally designed by famed architect Kirtland Cutter and constructed in 1909 by Washington Power Company. The substation distributes electrical power generated by the Upper Falls and the Monroe Street hydroelectric plants.


Avista sought technical expertise and professional engineering services for the completion of a field service project. Delta Star’s Engineering and Field Service teams would need to retrofit two (2) Upper Level Substation transformers and two (2) Lower Level Generation transformers cooling systems. The retrofits would need to incorporate the relocation of cooling from water cooled Oil Forced Water Forced (OFWF), fed from a river, to Oil Forced Air Forced (OFAF) coolers eliminating the discharge of cooling water into the river.


Delta Star Field Service implemented a design of a forced air OFAF cooling system for two substation transformers and two generation transformers.

The design incorporated:

  • Equipment Platforms
  • Pipe Supports
  • Wall Penetrations
  • Electric Service Requirements
  • System Ventilation
  • Cubic Feet per Minute (CFM) of Air Flow

Delta Star engineers designed air intake and exhaust systems to ensure there would be no impacts or alterations to the historic brick or windows of the Post Street building. The design and engineering drawings were in compliance with Avista drafting standards.


Delta Star’s Field Service team provided superior and comprehensive service to ensure all four (4) transformers were able to operate at peak performance with a focus on preventive maintenance. This effort minimizes future unscheduled maintenance while maximizing the life of each transformer.

Delta Star personnel used extreme care in observance with all safety rules and procedures established by state and local safety rules and regulations, ensuring public safety was of the upmost importance.

With nationwide coverage and response times as early as 24-hours, Delta Star Field Service was able to resolve a pressing situation effecting the Post Street Substation historical site, while providing a more energy-efficient solution for Avista and customers throughout eastern Washington.

About Delta Star

Headquartered in Lynchburg, Va., Delta Star, Inc. is a substation leader that provides superior, innovative client solutions that meet energy needs of the future, through a culture of best-in-class customer service. Stay up to date with Delta Star, Inc. on LinkedIn, Facebook, Twitter and Youtube.