Path 66

California Oregon Intertie (COI), identified as Path 66 by Western Electricity Coordinating Council (WECC), is a corridor of three roughly parallel 500 kV alternating current power lines connecting the electric grids of Oregon and California.

The project manager is the Transmission Agency of Northern California (TANC), a joint venture of several public utilities.

These substations, just north of the California-Oregon border, link to both the PacifiCorp and Bonneville Power Administration (BPA) grids in the Pacific Northwest.

It then turns west and climbs in elevation and reaches its highest point near Grizzly Peak at about 6,000 ft (1,830 m).

[3] From Olinda Substation, the TANC 500 kV continues as a single-circuit line, although the tower structures change (see photos below) to a two-level pylon.

There is a series capacitor station near Maxwell in Colusa County to boost the line across the long Olinda-Tracy segment.

The other circuit turns south to head for the Los Banos Substation as a southern extension of the third 500 kV line.

[4] The northern part of this electrical transmission corridor (including Path 15) is visible from space and Google Earth as lines of bare, treeless ground.

This is because the power lines here run through forests of conifer trees which appear dark green-green from space.

[3] The land through here has been logged and sometimes clear-cut to create a right-of-way for the power lines because a wildfire could start when an electrical arc occurs between the wires and a tree if they come close enough to each other.

This is because much of the segment between the Olinda and Tracy substations was constructed by upgrading an existing double-circuit 230 kV line.

A portion of the former 230-kV line south of the Sacramento River remains in service today as part of the 69 kV system that serves the pumping stations on the Contra Costa Canal.