Background

Stehekin Power System

The hydroelectric plant in Stehekin is capable of generating up to 180 KW. When demand is higher than 180 KW, a secondary source diesel generator (also referred to as D2) turns on to add up to 75 KW of additional capacity. The generator runs for at least 30 minutes each time demand is over 180 KW. If the demand exceeds the capacity of both the hydro and D2 (255 KW), both the hydro and D2 shut down, and two emergency diesel generators (known as D1 and D4) kick on to meet the demand.

Graphic describing power generation in Stehekin and impact of demand on generation

Concerns with the use of diesel generators:

  • Intended use is for emergency backup only (not peak demand)
  • Manual operation required to switch the emergency generators (causes power interruptions)
  • Reliability and power quality issues
  • Impacts the lifespan of the equipment
  • Environmental impacts
  • Potential future rate increases due to increased maintenance and operations costs
  • Inability to meet future electrical demand in the Stehekin Valley
Constraints in Stehekin