Mohave Power Station
Encyclopedia
Mohave Power Station was a 1,580 megawatt coal
fired power plant located in Laughlin
, Nevada
. Southern California Edison
is the majority owner of the plant and was its operator. The plant is currently shut down and in the process of being dismantled.
The plant was composed of two units of capable of generating 790 MW electrical each. Combustion Engineering supplied the boilers and GE supplied the turbines and generators. Bechtel performed engineering, procurement and construction.
The Mohave Generating Station was built on a 2500 acres (1,011.7 ha) site in the Sonora Desert adjacent to the Colorado River
in Laughlin
, Clark County
. It had supercritical boilers and cross-compound steam turbines. The plant was owned by a utility consortium of operator Southern California Edison Co (56%), LADWP (10%), Nevada Power (14%), and Salt River Project
(20%).
Mohave was the only power plant in the United States that used coal delivered by coal-slurry pipeline. The 18 inches (45.7 cm) diameter Black Mesa Pipeline ran 275 miles (442.6 km) to the plant from the Peabody Energy
Black Mesa Mine in Kayenta, AZ, and could deliver 660 short tons (589.3 LT) per hour. The land where the mine is located is owned by the Navajo
and Hopi
tribes. Four 8-million-gallon storage tanks each held the equivalent of 20000 short tons (17,857.1 LT) of dry coal. The slurry transport water was recycled for cooling tower water makeup; this and all other waste water was reused, making Mohave a zero-discharge facility. A natural-gas line run to the facility from a gas main near Topock supplied the required heat to start the plant, although the line was too small to run the plant exclusively on gas. The power was transmitted via two 500kV lines to substations in southern Nevada and southern California.
A report on the accident was completed in May, 1991, but was not released until Christmas Day because of Edison's objections that it would compromise civil suits.
Although several factors contributed to the pipe's failure, the report said Edison's actions—or lack of actions—were "primary and critical factors in causing the accident":
The report found no evidence that the accident was caused by a specific action on the day of the pipe failure.
The report recommended sweeping changes to Edison's policies, including annual reports to the PUC on the utility's safety training, inspection and maintenance programs. In addition, the report argues that, because the accident was avoidable, the costs should be borne by Edison's shareholders, not its rate-paying customers.
The plant was shut in Dec 2005 to comply with a consent agreement reached to settle a 1998 CAA lawsuit brought by several environmental groups. The plant had been targeted as a major source of pollution in the Grand Canyon and other locations to the east. Furthermore, the Hopi and Navajo signed an agreement preventing the use of water from the local aquifer to make up slurry. Various plans were presented, including selling the plant and retrofitting it to burn natural gas, although the latter would have required construction of a second high pressure gas line from Topock, 30 miles (48.3 km) to the south. Another option would have been to install exhaust scrubbers, which would have cost $1 billion.
In May 2007, SCE discontinued efforts to restart or sell the plant.
Dismantling got underway in October 2009 and is expected to take 2 years and cost $30 million. About 300 staff lost their jobs when the plant was closed.
On March 11, 2011, the 500 feet (152.4 m) exhaust stack, a longtime landmark of the Laughlin/Bullhead City area, was felled by explosives.
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
fired power plant located in Laughlin
Laughlin, Nevada
Laughlin is a census-designated place in Clark County, Nevada, United States, and a port located on the Colorado River. Laughlin is south of Las Vegas, located in the far southern tip of Nevada. It is best known for its gaming, entertainment, and water recreation. As of the 2010 census, the...
, Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
. Southern California Edison
Southern California Edison
Southern California Edison , the largest subsidiary of Edison International , is the primary electricity supply company for much of Southern California, USA. It provides 14 million people with electricity...
is the majority owner of the plant and was its operator. The plant is currently shut down and in the process of being dismantled.
The plant was composed of two units of capable of generating 790 MW electrical each. Combustion Engineering supplied the boilers and GE supplied the turbines and generators. Bechtel performed engineering, procurement and construction.
The Mohave Generating Station was built on a 2500 acres (1,011.7 ha) site in the Sonora Desert adjacent to the Colorado River
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...
in Laughlin
Laughlin, Nevada
Laughlin is a census-designated place in Clark County, Nevada, United States, and a port located on the Colorado River. Laughlin is south of Las Vegas, located in the far southern tip of Nevada. It is best known for its gaming, entertainment, and water recreation. As of the 2010 census, the...
, Clark County
Clark County, Nevada
-Demographics:As of the census of 2000, there were 1,375,765 people, 512,253 households, and 339,693 families residing within the MSA. The racial makeup of the MSA was 71.6% White , 9.1% Black, 5.7% Asian, 0.8% American Indian and 12.8% of other or mixed race. 22.0% were Hispanic of any race...
. It had supercritical boilers and cross-compound steam turbines. The plant was owned by a utility consortium of operator Southern California Edison Co (56%), LADWP (10%), Nevada Power (14%), and Salt River Project
Salt River Project
The Salt River Project is the umbrella name for two separate entities: the Salt River Project Agricultural Improvement and Power District, an agency of the state of Arizona that serves as an electrical utility for the Phoenix metropolitan area, and the Salt River Valley Water Users' Association, a...
(20%).
Mohave was the only power plant in the United States that used coal delivered by coal-slurry pipeline. The 18 inches (45.7 cm) diameter Black Mesa Pipeline ran 275 miles (442.6 km) to the plant from the Peabody Energy
Peabody Energy
Peabody Energy Corporation , previously Peabody Coal Company, is the largest private-sector coal company in the world. The company is headquartered in Downtown St. Louis, Missouri....
Black Mesa Mine in Kayenta, AZ, and could deliver 660 short tons (589.3 LT) per hour. The land where the mine is located is owned by the Navajo
Navajo people
The Navajo of the Southwestern United States are the largest single federally recognized tribe of the United States of America. The Navajo Nation has 300,048 enrolled tribal members. The Navajo Nation constitutes an independent governmental body which manages the Navajo Indian reservation in the...
and Hopi
Hopi
The Hopi are a federally recognized tribe of indigenous Native American people, who primarily live on the Hopi Reservation in northeastern Arizona. The Hopi area according to the 2000 census has a population of 6,946 people. Their Hopi language is one of the 30 of the Uto-Aztecan language...
tribes. Four 8-million-gallon storage tanks each held the equivalent of 20000 short tons (17,857.1 LT) of dry coal. The slurry transport water was recycled for cooling tower water makeup; this and all other waste water was reused, making Mohave a zero-discharge facility. A natural-gas line run to the facility from a gas main near Topock supplied the required heat to start the plant, although the line was too small to run the plant exclusively on gas. The power was transmitted via two 500kV lines to substations in southern Nevada and southern California.
1985 pipe failure disaster
On June 9, 1985, a 30 inches (76.2 cm) hot reheat line, under 600 pounds per square inch of pressure, burst open. The reheat line cycles steam back through the boiler stack after it has expanded through the high pressure (HP) turbine and before it reaches the low pressure (LP) turbine. A 1,000-degree steam cloud blew down a door leading to the control room of the station, fatally scalding six workers: Michael Bowman, John Dolan, Ernest Hernandez, Terry Leroy, Danny Norman and Howard Turner. Ten others were injured. The station was out of service for six months while all the steam piping was replaced.A report on the accident was completed in May, 1991, but was not released until Christmas Day because of Edison's objections that it would compromise civil suits.
Although several factors contributed to the pipe's failure, the report said Edison's actions—or lack of actions—were "primary and critical factors in causing the accident":
- Edison knowingly operated the system at temperatures above design specification for long periods of time, and operators were unable to control the temperatures within the system as a result of a "design flaw."
- Even so, the pipe, part of a steam reheat system, was not routinely maintained or inspected, though the pipe shifted and distorted because of exposure to abnormal stresses, the report said.
- Edison's management made high production a priority over safety. In 1979, Edison disciplined a supervisor for ordering an unauthorized inspection of unrelated pipe welds. "The fear SCE management has instilled in its employees is counterproductive to safety and increases the chances that additional incidents as serious as this one may occur in the future," the report said.
The report found no evidence that the accident was caused by a specific action on the day of the pipe failure.
The report recommended sweeping changes to Edison's policies, including annual reports to the PUC on the utility's safety training, inspection and maintenance programs. In addition, the report argues that, because the accident was avoidable, the costs should be borne by Edison's shareholders, not its rate-paying customers.
Shutdown
The plant was shut down on December 31, 2005 with the possibility it might not reopen. With the shutdown of the plant, the mine providing the coal was closed. This closure had a major negative impact on the Hopi.The plant was shut in Dec 2005 to comply with a consent agreement reached to settle a 1998 CAA lawsuit brought by several environmental groups. The plant had been targeted as a major source of pollution in the Grand Canyon and other locations to the east. Furthermore, the Hopi and Navajo signed an agreement preventing the use of water from the local aquifer to make up slurry. Various plans were presented, including selling the plant and retrofitting it to burn natural gas, although the latter would have required construction of a second high pressure gas line from Topock, 30 miles (48.3 km) to the south. Another option would have been to install exhaust scrubbers, which would have cost $1 billion.
In May 2007, SCE discontinued efforts to restart or sell the plant.
Dismantling
On June 10, 2009, Southern California Edison announced that the Mohave Generating Station would be decommissioned and all generating equipment would be removed from the site. Later, SCE announced that all administrative buildings on site would also be razed. The only structure remaining on the property will be the 500kV switchyard, which will continue to serve as a switching location for the bulk power system as well as provide electricity to a nearby Nevada Power substation supplying the Laughlin area.Dismantling got underway in October 2009 and is expected to take 2 years and cost $30 million. About 300 staff lost their jobs when the plant was closed.
On March 11, 2011, the 500 feet (152.4 m) exhaust stack, a longtime landmark of the Laughlin/Bullhead City area, was felled by explosives.
Owners
- Southern California EdisonSouthern California EdisonSouthern California Edison , the largest subsidiary of Edison International , is the primary electricity supply company for much of Southern California, USA. It provides 14 million people with electricity...
(56%) - Salt River ProjectSalt River ProjectThe Salt River Project is the umbrella name for two separate entities: the Salt River Project Agricultural Improvement and Power District, an agency of the state of Arizona that serves as an electrical utility for the Phoenix metropolitan area, and the Salt River Valley Water Users' Association, a...
(20%) - Nevada Power CompanyNevada Power CompanyNevada Power Company is a Las Vegas-based company that produces, distributes and sells electricity in southern part of the U.S. state of Nevada. As of 2005, Nevada Power had over 700,000 electric customers in parts of three Nevada counties creating a service area of more than...
(14%) - Los Angeles Department of Water and PowerLos Angeles Department of Water and PowerThe Los Angeles Department of Water and Power is the largest municipal utility in the United States, serving over four million residents. It was founded in 1902 to supply water and electricity to residents and businesses in Los Angeles and surrounding communities...
(10%)