Dual Circuit 500kV power lines crossing I580

California Oregon Intertie (COI), identified as Path 66 by

Western Electricity Coordinating Council The Western Electricity Coordinating Council (WECC) promotes Bulk Electric System (BES) reliability for the entire Western Interconnection system. WECC is the Regional Entity responsible for compliance monitoring and enforcement. In addition, WE ...

(WECC), is a corridor of three roughly parallel 500 kV

alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...

power lines Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a ''transmission network''. This is d ...

connecting the electric grids of

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

and

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. Their combined power transmission capacity is 4800 MW. Two of the power lines run from Malin Substation southeast of

Klamath Falls, Oregon Klamath Falls ( ) is a city in and the county seat of Klamath County, Oregon, United States. The city was originally called ''Linkville'' when George Nurse founded the town in 1867. It was named after the Link River, on whose falls the city was ...

to Round Mountain Substation northeast of

Redding, California Redding is the economic and cultural capital of the Shasta Cascade region of Northern California and the county seat of Shasta County. Redding lies along the Sacramento River, north of Sacramento, and south of California's northern border wi ...

. One of them is owned by

Western Area Power Administration As one of the four power marketing administrations within the U.S. Department of Energy, the Western Area Power Administration (WAPA)'s role is to market wholesale hydropower generated at 57 hydroelectric federal dams operated by the Bureau of R ...

, the other by

Pacific Gas and Electric The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered in the Pacific Gas & Electric Building, in San Francisco, California. PG&E provides natural gas and electricity to 5.2 milli ...

and

PacifiCorp PacifiCorp is an electric power company in the western United States. PacifiCorp has two business units: # Pacific Power, a regulated electric utility with service territory throughout Oregon, northern California, and southeastern Washington. # ...

jointly. These lines are a part of Pacific AC Intertie and were completed in the 1960s. The third line runs from

Captain Jack Captain Jack may refer to: People * Calico Jack (1683–1720), a pirate in the 18th century * Captain Jack (Hawaiian) (died 1831), Naihekukui, commander of Kamehameha's fleet and father of Kalama * Captain Jack (fl. 1830s on), Kaurna man in c ...

Substation near Malin to Olinda Substation south of Redding. It is a part of California-Oregon Transmission Project, the project manager is the Transmission Agency of Northern California (TANC), a joint venture of several public utilities. It was completed in 1993.

Route

Path 66 is composed of one segment of TANC, PG&E and PacifiCorp 500 kV lines. The TANC line route starts at Captain Jack Substation (42° 4' 38.06"N 121° 23' 25.47"W) close to Malin, close to the California-Oregon border, near the Malin Substation, where the other 500 kV lines start (PacifiCorp & PG&E). These substations link to both the

and

Bonneville Power Administration The Bonneville Power Administration (BPA) is an American federal agency operating in the Pacific Northwest. BPA was created by an act of Congress in 1937 to market electric power from the Bonneville Dam located on the Columbia River and to constr ...

(BPA)

grid Grid, The Grid, or GRID may refer to: Common usage * Cattle grid or stock grid, a type of obstacle is used to prevent livestock from crossing the road * Grid reference, used to define a location on a map Arts, entertainment, and media * News g ...

in the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...

.Route descriptions and tower designs are based on Google Earth images. ;Path 66 - Captain Jack to Olinda Path 66 consists of the northernmost segment of TANC's 500 kV line from Captain Jack substation to Tracy substation in California's Central Valley. Leaving Captain Jack substation, the line first heads southeast as a single-circuit line and runs parallel with the other two 500 kV lines across the Modoc Plateau. It then turns west and climbs in elevation and reaches its highest point near Grizzly Peak at about .

Google Earth Google Earth is a computer program that renders a 3D computer graphics, 3D representation of Earth based primarily on satellite imagery. The program maps the Earth by superimposition, superimposing satellite images, aerial photography, and geog ...

elevation for

GNIS The Geographic Names Information System (GNIS) is a database of name and locative information about more than two million physical and cultural features throughout the United States and its territories, Antarctica, and the associated states of ...

coordinates. From there, it heads south, spanning over the

Stonecoal Valley Canby is a census-designated place in Modoc County, California. It is located west of Alturas, at an elevation of 4314 feet (1315 m). Its population is 183 as of the 2020 census, down from 315 from the 2010 census. The ZIP Code is 96015. The com ...

and the

Pit River The Pit River is a major river draining from northeastern California into the state's Central Valley. The Pit, the Klamath and the Columbia are the only three rivers in the U.S. that cross the Cascade Range. The longest tributary of the Sacr ...

. Near Round Mountain, it turns southwest and the line is joined by two 230-kV lines as all three lines head into the

Sacramento Valley , photo =Sacramento Riverfront.jpg , photo_caption= Sacramento , map_image=Map california central valley.jpg , map_caption= The Central Valley of California , location = California, United States , coordinates = , boundaries = Sierra Nevada (ea ...

. As the line passes by Cottonwood, it turns west and crosses

Interstate 5 Interstate 5 (I-5) is the main north–south Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels through the states of Califor ...

. Near Olinda, it turns south and enters Olinda substation. Here the line interconnects with transmission lines carrying power from

Shasta Dam Shasta Dam (called Kennett Dam before its construction) is a concrete arch-gravity dam across the Sacramento River in Northern California in the United States. At high, it is the eighth-tallest dam in the United States. Located at the north e ...

and

Keswick Dam Keswick Dam is a concrete gravity dam on the Sacramento River about northwest of Redding, California. Part of the U.S. Bureau of Reclamation's Central Valley Project, the dam is high and impounds the Keswick Reservoir, which has a capacity of ...

. ;Connecting wires to Path 15 - Olinda to Tracy 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. The line proceeds south and then southeast along the western edge of the Sacramento Valley. It parallels

(about four miles (6.5 km) to the west) on its way south, although it's barely visible. It also parallels two 230-kV

lines for much of this segment and another WAPA 230 kV line. There is a series capacitor station near Maxwell in

Colusa County Colusa County () is a county located in the U.S. state of California. As of the 2020 census, the population was 21,839. The county seat is Colusa. It is in the North Valley of California, northwest of the state capital, Sacramento. History C ...

to boost the line across the long Olinda-Tracy segment. The line crosses the two separated PG&E 500-kV lines, near

Woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

and Rio Vista. Near

Antioch Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ� ...

the line turns and runs parallel with the two PG&E 500 kV lines. All three lines cross both the Sacramento and San Joaquin Rivers on very large pylons. The TANC line turns away from the PG&E lines and heads for another large substation near Tracy. ;Connecting wires to Path 15 - Tracy to intersection with PG&E wire From Tracy Substation, the line again to a rare, tall, double-circuit 500 kV line suspended by a three-level pylon located in the

San Joaquin Valley The San Joaquin Valley ( ; es, Valle de San Joaquín) is the area of the Central Valley of the U.S. state of California that lies south of the Sacramento–San Joaquin River Delta and is drained by the San Joaquin River. It comprises seven c ...

. The line terminates where it intersects with one of the two PG&E 500 kV lines as the PG&E heads

south South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...

from the Tesla substation towards Los Banos Substation. The PG&E line that the dual-circuit line intersects used to be a second Los Banos-Tesla power line that was split apart. A PG&E tower was removed, although the foundation for the tower is still visible. New towers were built to accompany the line changes. One circuit turns north back into Tesla Substation, effectively linking the Tracy Substation with the Tesla Substation. The other circuit turns south to head for the Los Banos Substation as a southern extension of the third 500 kV line. ;Path 66 - Malin to Round Mountain The other two 500 kV lines start in the Malin substation to the east of the Captain Jack substation. One circuit of a rare, tall BPA dual-circuit and one single-circuit 500 kV line connect Captain Jack substation with Malin substation. The PG&E and PacifiCorp 500 kV line both head south together across the Modoc Plateau, generally following the lone WAPA line at a distance. The parallel lines then turn southwestward climb to about 5,400 feet (1,645 m), before descending and turning south once again. Both lines enter the Round Mountain substation. This is the terminus of the Path 66 portion of the parallel 500 kV wires.

Substations

;Path 66 TANC line (North to South) *Captain Jack *Olinda PG&E and PacifiCorp *Malin *Round Mountain ;Connecting power line *Series capacitor station in

*Tracy

Issues

;Power transmission capacity Path 66 can transmit 4,800 MW of

electrical power Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions of ...

from north to south. From south to north, the system can transmit only 3,675 MW of power. ;Environmental impacts The northern part of this electrical transmission corridor (including Path 15) is visible from space and

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. 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.

Tower design and differences

This TANC 500 kV power line, unlike its PG&E counterparts, is triple-bundled, meaning that it has three-wires per

phase Phase or phases may refer to: Science *State of matter, or phase, one of the distinct forms in which matter can exist *Phase (matter), a region of space throughout which all physical properties are essentially uniform * Phase space, a mathematic ...

, whereas the PG&E lines are only double-bundled, or two wires per phase. In addition, the tower's design is strikingly different from the lighter and wider PG&E tower, and the design also changes significantly as one goes from north to south on WAPA's 500 kV line. The TANC line changes design at the Olinda substation from the delta pylon pictured at the Interstate 5 crossing to the two-level pylon pictured above. This is because much of the segment between the Olinda and Tracy substations was constructed by upgrading an existing double-circuit 230 kV line. The segment of TANC's 500 kV line from the Sacramento River crossing south to the Tracy Substation has delta pylons like those found on the Captain Jack-Olinda segment, although they are slightly different. This is because south of the Sacramento River crossing, the original 230 kV line paralleled the two PG&E 500 kV lines almost all the way to Tracy Substation. In order to meet separation requirements, a new alignment for the 500 kV line had to be built some distance to the east, with the exception of the San Joaquin River crossing, which utilizes the former 230 kV facilities. This alignment can be seen from Highway 4 and the western part of the

San Joaquin River The San Joaquin River (; es, Río San Joaquín) is the longest river of Central California. The long river starts in the high Sierra Nevada, and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suis ...

portion of the

Sacramento River Delta ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento C ...

. 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 The Contra Costa Canal is a aqueduct in the U.S. state of California. Its construction began in 1937, with delayed completion until 1948 due to World War II shortages in labor and materials. A portion of the canal's right of way has been develope ...

. As for the pylons of the PG&E and PacifiCorp Round Mountain-Malin parallel lines, the PG&E line uses the same tower type as the PG&E Table Mountain-Round Mountain 500 kV segment does. The PacifiCorp 500 kV line uses a pylon that looks similar to the pylon used in WAPA's Olinda-Captain Jack segment. ;Visual reference File:DSCN2133_WAPA_500kV.JPG, WAPA Olinda-Tracy 500 kV transmission line outside of

Vacaville Vacaville is a city located in Solano County in Northern California. Sitting approximately from Sacramento and from San Francisco, it is within the Sacramento Valley. As of the 2020 census, Vacaville had a population of 102,386, making it th ...

It's about to cross

Interstate 80 Interstate 80 (I-80) is an east–west transcontinental freeway that crosses the United States from downtown San Francisco, California, to Teaneck, New Jersey, in the New York metropolitan area. The highway was designated in 1956 as one o ...

. File:Pacific Gas and Electric 500 kV power lines.JPG, PG&E wires near Tracy. File:PG&E wire spanning over WAPA line.JPG, PG&E 500 kV Table Mountain-Vaca Dixon line spanning over the WAPA line (Olinda-Tracy segment).

Problems

Since TANC's Captain Jack-Olinda 500 kV wire rises to almost as the line crosses the rugged mountains near Grizzly Peak, that section of 500 kV line is covered with large amounts of snow during the winter. Despite its location far from the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

, of snow can accumulate near Grizzly Peak's -summit. The extreme snowfall there can cause ice and snow to accumulate on the insulators and the wires and sometimes lead to power outages when the wires snap in these extreme conditions. This high-elevation segment of 500 kV line is also said to be problematic.

Map

File:Path_15_2.GIF, Map of Path 66 located in the upper section, left of the other two 500 kV lines south of Round Mountain substation

References

External links

WAPA.gov
{{coord missing, California Western Interconnection Energy infrastructure in California PacifiCorp