Path 66 is the name of a 500 kV power line that was built by Western Area Power Administration (WAPA) in the early 90's and completed (energized) in 1993. It's the northern half of one of the three 500 kV lines that makes up the Pacific AC Intertie which is the AC portion of the greater Pacific Intertie project linking power grids in the Southwest with the grids in the Pacific Northwest (for more info see Path 15). Also, this is the larger and older of the two segments of the Pacific AC Intertie that WAPA worked on, the other is this. The 350-mile (567 km) power line is in the California Central Valley, moreover the Sacramento Valley, for most of the time.
The route technically starts at where a rare, tall, dual-circuit 500 kV line 'picks up' a PG&E 500 kV line heading south from the Tesla substation and one heading north from the Los Banos substation in the San Joaquin Valley.
The dual-circuit 500 kV wire heads north and ends at the Tracy substation west of Tracy and close to the Clifton Court Forebay. From here on north, a single-curcuit 500 kV wire heads to the northwest, closely paralleling the two PG&E lines that make up the rest of the electron highway. The three wires cross together over the San Joaquin River and the Sacramento River in the Sacramento-San Joaquin River Delta. The two spans of three power lines each, just to the east of the confluence of the Sacramento and San Joaquin Rivers, utilize massive pylons in order to raise the wires high enough to safely cross both rivers. After the crossing, the PG&E power lines split, one heads to the northwest and the other to the northeast. This power line parallels the one that heads northwest and stays in the western part of the Sacramento Valley. It parallels Interstate 5 (about four miles (6.5 km) to the west)on its way north, although it's barely visible. Somewhere north of Red Bluff and Cottonwood, the power line turns to the northeast and crosses Interstate 5 once and only once. The power line begins its ascent on its way to the Modoc Plateau and it meets up with the other two 500 kV lines there. The path ends in the Captain Jack substation close to Malin, the California-Oregon border, and the Malin substation, where the other 500 kV lines terminate.
Tower Design and Differences
This 500 kV power line, unlike its PG&E counterparts, is triple-bundled, mean that it has three-wires per phase, whereas the PG&E lines is only double-bundled, or two wires per phase. In addition, the tower's design is strikingly different from the lighter, wider, but structurally thinner PG&E wires and the design also changes as one goes from south to north on Path 66. For a comparison, see below:
Also, compare the above WAPA 500 kV wire picture with its lone crossing of Interstate 5 (located visually in between the two 230 kV tower in the foreground) and from a different angle (large, steel lattice tower in the background). The segment of Path 66 from the San Joaquin River crossing to the Tracy substation has towers resembling the tower pictured in the Interstate 5 crossing, but the tower is structrally different. It can be seen from Highway 4 and the western part of the San Joaquin River portion of the Delta.
