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Path 46, also called West of Colorado River, Arizona-California West-of-the-River Path (WOR), is a set of many high-voltage alternating-current transmission lines that are located in southeast California and Nevada up to the Colorado River. This power transmission system is essential to meet the electricity demands of Southern California's massive population centers like Los Angeles and San Diego. The massive system has three separate systems of power lines.
Individual power lines of Path 46
- Supporting system (230 kV only)
- El Centro - Imperial Valley 230 kV
- Ramon - Mirage 230 kV
- Coachella - Devers 230 kV
- Southern System (500 kV only)
- North Gila - Imperial Valley 500 kV
- Palo Verde - Devers 500 kV No.1
- Northern System
- Marketplace - Adelanto 500 kV - although this line is called Path 64, it is part of Path 46.
- Eldorado - Lugo 500 kV
- Eldorado - Lugo 230 kV lines 1 & 2
- Mohave - Lugo 500 kV
- Julian Hinds - Mirage 230 kV
- McCullough - Victorville 500 kV lines 1 & 2
- Hoover - Victorville 287 kV
Although the Intermountain HVDC line follows the route of the northern system (specifically, the Hoover - Victorville and McCullough - Victorville lines) the DC line is not considered part of Path 46. Instead, the line is a distinct path: Path 27.
Route of the 500 kV lines
- North Gila - Imperial Valley (San Diego Gas and Electric)
The power line begins in the Imperial Valley substation located west of Mexicali between the United States-Mexico border to the south and Interstate 8 to the north. The same substation is also the northern end of Path 45, an international power transmission corridor linking the Californian power grid to the Mexican power grid. Leaving the substation, the line parallels Interstate 8 at a distance to the south as both Interstate and power line head east. At a certain distance to the east near the sand dunes, Interstate 8 parallels the line closely, as infrastructure bunches up to cross the shifting sand dunes. For the next 10 miles (16 km), the line is squeezed tightly between the US-Mexico border and Interstate 8, until both Interstate 8 and the power line turn northeast. As Interstate 8 turns east again to reach Yuma, the line spans over and departs the freeway as the line continues northeast. The line reaches the foothills north of Yuma and heads east. Abruptly, as the line crosses the Colorado River, the power line turns south to head into the North Gila substation. Another line, Palo Verde - North Gila, connects this southern line to the Palo Verde Nuclear Power Plant. The section of line east of the Colorado River is referred to as Path 21.
Starting from the Devers substation northeast of the San Gorgonio Pass and north of Interstate 10, the line runs north of and roughly parallel to Interstate 10 as both head southeast and pass by Palm Springs. After dropping in elevation to near sea level near Indio, both the line and interstate climb about 1600-ft out of the Coachella Valley and into Shavers Valley. Upon entering Shavers Valley, the line crosses over I-10 near the Cactus City exit and continues to run parallel to Interstate 10 as both continue easterly across the Colorado Desert region of the Sonoran Desert. Both pass Chiriaco Summit and Desert Center with the line never more than 1.5 miles south of the freeway. About 5 miles after passing the Chuckawalla Valley State Prison, the line leaves the freeway area by turning south-east for a few miles before turning east to the Palo Verde Valley, Ripley, and eventually crossing the Colorado River south of Blythe. Like the North Gila - Imperial Valley line, the section of this power line east of the Colorado River is Path 21. The power line eventually ends in the massive Palo Verde substation adjacent to the nuclear power plant and with the southernmost line mentioned above.
A second 500-kV transmission line to be called Devers - Palo Verde No. 2 (DPV2) is planned to run parallel to the existing DPV1 line.
- Mojave - Lugo (SCE)
Starting from Lugo substation near Interstate 15, the 500 kV power line heads generally northeast along with the Eldorado - Lugo 500 kV line and two 230 kV power lines. Both lines cross vast expanses of desert and mountains as the head towards Nevada. Just south of Interstate 40, the Mojave - Lugo line splits from the Eldorado - Lugo; the Mojave line turns to head in a more easterly direction that the other 500 kV line. The line roughly parallels Interstate 40 at a large distance up to the California border. The power line then bends and heads northeast to the Mohave Power Station near Laughlin, Nevada. The power line terminates there along with a shorter SCE 500 kV line from Eldorado substation.
- Eldorado - Lugo (SCE)
The Eldorado - Lugo 500 kV line follows the same exact path as the Mojave - Lugo 500 kV until south of Interstate 40. The line then continues northeast through the desert along with other 230 kV power lines. Although the power lines generally parallel Interstate 15 through the desert, it does so at a very large distance and is completely out of sight. As the set of power lines leaves California and enters Nevada, it rises to an elevation of 5,000 feet (1,500 m) before turning to head north-northeast and descending. The 500 kV power line then joins two other SCE 500 kV powerlines, one from the Mojave Generating Station, and the other an SCE-built extension of Path 21 from central Arizona. All three lines terminate in the Eldorado substation, which is connected to the nearby McCullough and Marketplace substations via Path 62.
- McCullough - Victorville lines one and two (Los Angeles Department of Water and Power (LADW&P))
Both McCullough - Victorville power lines leave the Victorville substation heading northeast along with the Hoover - Victorville 287 kV line. The Intermountain DC 500 kV power line joins the group of three power lines a short distance later. As the power lines cross Interstate 15 for the first time, they turn and head in a more easterly direction to avoid Barstow. The lines then cross Interstate 40 for their only time and then Interstate 15 again. The set of four power lines generally parallels Interstate 15 at a distance north of the highway for the rest of the path in California. The Marketplace - Adelanto 500 kV power line parallels the group of four power lines for a short distance before the single line turns away and follows Interstate 15 closely instead. As the lines pass Clark Mountain to the north, they enter Nevada adjacent to Primm and Interstate 15. There the group of power lines, along with the Marketplace - Adelanto line that has come back, split and spread out through the desert, with power lines spanning over each other. After crossing some mountains, the McCullough - Victorville and the Hoover - Victorville 287 kV lines reunite and terminate in the McCullough substation, while several other lines bypass the substation and terminate in other locations, such as the Intermountain line.
- Marketplace - Adelanto (LADW&P)
The Marketplace - Adelanto line starts at the Adelanto substation west of the Victorville substation. The same substation is also the southern end of the Intermountain HVDC line at the Adelanto static inverter plant. As the line leaves the substation, it heads northwest along with U.S. Route 395 for a while before it turns east and then northeast as it meets the other Marketplace - Victorville lines and Interstate 15. The line follows the other Path 46 wires, diverges away and then Interstate 15 closely until the Nevada border, where the line abandons the freeway as the line heads east into the Marketplace substation.
Capacity and source of the electricity
The entire Path 46 system has a capacity of transmitting 10,623 megawatts (about 10 gigawatts) from east to west. It has no rating to transfer power from west to east and historically this never happens. It sends electric power to the cities of Southern California such as San Diego, Los Angeles, San Bernardino, Santa Ana, Temecula, Riverside and Bakersfield. The source of the electricity is from hydroelectric dams (like Hoover Dam) on the Colorado River, fossil fuel plants (like the Mohave Power Station in Laughlin), and nuclear power (like the Palo Verde Nuclear Plant).
A new 500 kV line called Devers - Palo Verde No. 2 (DPV 2) proposed by Southern California Edison (SCE) has been approved by both the California Public Utilities Commission (CPUC) and California Independent System Operator (Cal-ISO) in the years 2007 and 2005, respectively. The new 230-mile (370 km) 500 kV line will follow the existing DPV 1 - 500 kV from San Bernardino in California to the Harquahala Generating Station (near the Palo Verde Nuclear Plant) in Arizona and the line will cost USD 680 million to build. The new line and associated upgrades to the regional transmission system will bring an additional 1,200 MW of electrical power to the Los Angeles area, which is enough to power 780,000 homes.
In June 2007, the Arizona Corporation Commission rejected SCE's application for the line expansion. SCE then appealed to the FERC, and is currently working directly with ACC to find a solution. Construction on the California portion of the line could begin in 2009, but Arizona is not expected to respond before the end of 2009.
San Diego Gas & Electric has also proposed a new 500 kV power line, with its eastern terminus at the North Gila substation and several possibilities for the western terminus and route configuration.
Wildfires of October 2007
Power outage of September 2011
The 2011 Southwestern United States blackout that began on September 8, was a widespread power outage initiated by a mistake by an Arizona Public Service employee at the North Gila substation that caused the loss of the 500 kV Path 46 segment from Hassayampa to North Gila  that affected parts of western Arizona, Mexico's Sinaloa and northern Baja California, and also caused the largest power failure in Southern California history. Had the utilities affected realized the consequences to the loss of this line, they would have taken steps to eliminate the vulnerability. On April 27, 2012, the Federal Energy Regulatory Commission and the North American Electric Reliability Corporation released their report detailing the blackout and its causes. Most of the areas affected were served by San Diego Gas & Electric Company, and left more than 5 million people without power.
- Route descriptions are based on Google Earth images.
- Paths 41-50. Western Electricity Coordinating Council. 2006.
- Paths 61-70. Western Electricity Coordinating Council. 2006.
- Paths 21-30. Western Electricity Coordinating Council. 2006.
- "California's Major Electric Transmission Lines". California Energy Commission. 2005-11-09. Retrieved 2007-11-16.
- "Southern California Edison's Devers–Palo Verde No. 2 Transmission Line Project". California Public Utilities Commission. Retrieved 2007-11-16.
- "Transmission Projects Devers - Palo Verde No. 2". Southern California Edison. Retrieved 2007-11-16.
- "Devers-Palo Verde 2 - SCE to build a high-voltage transmission line between California and Arizona". Southern California Edison. Retrieved 2007-11-16.
- "Draft Environmental Impact Report / Environmental Impact Statement". California Public Utilities Commission. Retrieved 2007-11-16.
- "Arizona Regulators Reject Cross-Border Transmission Line". Energy Legal Blog. 2007-06-13.
- "SCE Seeking New Transmission Line Project". redOrbit. 2008-08-03.
- Jackson, Robert (2004-12-08). "SDG&E Transmission Comparison Study". California Independent System Operator. Retrieved 2007-12-10.
- "Fires wreak havoc on region's electricity supply". Jeran Wittenstein (San Diego Daily Transcript). October 23, 2007. Retrieved 2007-10-26.
- Effron, Lauren (9/8/2011). "One Electrical Worker Blamed for Leaving Millions Without Power in California, Arizona and Mexico". ABC News. Retrieved 10 September 2011.
- Medina, Jennifer (September 10, 2011). "Human Error Investigated in California Blackout’s Spread to Six Million". The New York Times. p. A15. Retrieved September 10, 2011. "The day after the largest power failure in California history left millions in Southern California, western Arizona and northern Mexico without electricity during one of the hottest weeks of the year, local and federal officials promised Friday to investigate the cause."
- Allen, Sam (2011-09-09). "Arizona power company baffled by events that led to outage". Los Angeles Times. Retrieved 10 September 2011.
- Baker, Debbi (2011-09-09). "Power restored to all 1.4 million customers". San Diego Union Tribune. Retrieved 10 September 2011.