LADWP Power
ANTICIPATING LOTS OF ATTENTION GOING to the Los Angeles Aqueduct in this year of its centennial, and to the legendary accomplishments of the water side of the Los Angeles Department of Water and Power, the CLUI started planning an exhibition about the power side of the DWP’s system two years ago, visiting the full spectrum of the utility’s operations, from far-flung power production plants to small distribution substations scattered around the city that they serve.
LADWP Power: Electricity in Los Angeles opened at the CLUI exhibit space in November 2013, (coinciding with the L.A. Aqueduct’s centennial celebration) and will be on display through February 16, 2014. The exhibit includes a tour program and a version on the CLUI website.
The Los Angeles Department of Water and Power is the largest municipal utility in the nation, serving four million inhabitants of the city (though not the other eight million in the surrounding cities of the Southland). It is culturally identified with Los Angeles, part of its fictionalized blend of Deco-noir.
DWP is famous for its water service, which began 100 years ago with the opening of the Los Angeles Aqueduct. But its electrical service accounts for far more of its budget, and dates back further. Though water is certainly essential to the city, the power of DWP comes from power.
DWP has 8,800 employees and a $4 billion annual budget, serving an area of 465 square miles. DWP has more than a dozen maintenance and engineering centers, extending from downtown to Owens Lake; four large gas-fired power plants; 13 hydro-electric plants; two of the nation’s largest DC inverter stations; 3,656 miles of transmission lines; more than 10,000 miles of distribution lines; and 321,781 distribution line utility poles.
DWP started as one of several water and power providers in Los Angeles in 1902, and grew by buying other companies, finally becoming LADWP in 1937, when Boulder Dam power flooded the utility’s energy capacity. Prior to the dam, DWP energy came from small to medium-sized hydro-electric stations along the L.A. Aqueduct. While William Mulholland made the water flow, Ezra Scattergood, head of the department’s electrical division, figured out how to harvest the energy from this engineered 233 mile-long waterfall to power the city.
Sources of Power
DWP provides up to 6,500 megawatts of power to its 1.5 million paying customer accounts. Nearly a quarter of that power comes from power plants within the Los Angeles basin. The rest comes from elsewhere, including the Owens Valley, and as far away as the Columbia River in the Pacific Northwest, and the coal fields of central Utah. The city’s reach for energy extends even further than its reach for water.
The largest single source of electricity for DWP is the Intermountain Power Plant, located in the middle of Utah, and fueled by coal mined from the eastern part of the state, which arrives by train. The construction of the plant started in 1981. By the time the two boiler units went online in 1987, the project cost $4.5 billion. The DWP initiated the project and operates the plant. More than 80% of its 1,900 megawatt capacity output goes directly to Southern California via a dedicated high voltage DC line, one of two long-distance DC lines operated by the department. The DWP has pledged to use less power from the plant, and to convert it to natural gas over the next ten years.
The second largest single source of power to DWP is the Navajo Generating Station, a coal-fired plant near Page, Arizona. It has an output capacity of 2250 megawatts, even larger than the Intermountain Plant. The Navajo Generating Station was built starting in 1970, on a Navajo Reservation, and is operated by the Salt River Project, a utility providing electricity and water to the cities of Arizona. The DWP has a 21% share in the plant. Coal comes via a dedicated railway connecting the plant to the Kayenta mines on Black Mesa, 78 miles to the south.
Around a quarter of the power consumed by DWP comes from four gas-fired power plants, owned and operated by the department, and all located inside the Los Angeles basin. The Valley Generating Station, in the San Fernando Valley community of Sun Valley, was built in 1953, and is the oldest of them. The plant is also the location of the Truesdale Training Center, DWPs main training center for electrical line workers, and the site of the annual lineman’s rodeo.
The Scattergood Generating Station was built a few years later, in 1958, and looms above the beach at Playa del Rey, next to the Hyperion Water Treatment Plant, the main sewage treatment plant for the city. It has three gas-fired units, and produces around 800 megawatts. The Haynes Generating Station in Long Beach has six units and generates up to 1,580 megawatts, and the Harbor Generating Station in Wilmington, also near the harbor, generates 450 megawatts.
DWP has a 5.7% stake in the Palo Verde Nuclear Generating Station, located outside Phoenix, Arizona, enough to supply up to 11% of DWP power needs. Palo Verde is the largest nuclear power complex in the country. The facility cost nearly $6 billion, and took twelve years to build, with the last reactor completed in 1988. With a net capacity of 3,663 megawatts, the three reactor units generate power for nearly 4 million people–a major source of electricity for Phoenix and Southern California.
Around 10% of DWP power comes from hydroelectric plants. The DWP built one of the longest DC power transmission lines in the country to connect Los Angeles with the tremendous electrical generation capacity from Federal dams along the Columbia River in the Pacific Northwest. Known as the Pacific Intertie, this line starts at the Celilo Converter Station, above the Dalles Dam, on the Oregon side of the river. The line runs for 850 miles through Oregon and Nevada, then follows the DWP’s Owens Gorge AC line through the Owens Valley. It terminates at a converter station in Sylmar, next to where the Los Angeles Aqueduct spills into the city at the Cascades.
The line has a capacity of 3,100 megawatts, enough to meet nearly half of DWPs electrical demand, and has historically been a major source of power for DWP. Currently the line supplies only around 3% of DWP power. Most of the electricity from the Intertie is used by other local utilities, such as Southern California Edison. In the winter, when less air-conditioning use decreases the electrical demand in Southern California, and the Pacific Northwest’s heating needs increase, the line can be reversed, to send any surplus of energy in Southern California back up to the Northwest.
The other hydro-electric sources of power for DWP are a series of facilities generating electricity from the falling water of the Los Angeles Aqueduct, including two medium sized plants in San Francisquito Canyon, north of Santa Clarita. One of them, San Francisquito Power Plant #1, went online in 1917. It was the first source of hydropower directly for the city, and provided 97% of DWP power at that time.
The other, San Francisquito Power Plant #2, was built a few miles further downstream along the Aqueduct around 1926, a mile from the base of the San Francisquito Dam. The dam failed in 1928, in one of the worst industrial accidents in American history. More than 450 people were killed when the sudden rush of water flowed through the canyon, and through the Santa Clara River Valley to the ocean at Ventura, 50 miles away. Power Plant #2 was destroyed, but was quickly rebuilt. The dam was not. Ruins remain on site.
The other hydroelectric plants along the aqueduct are much smaller, generating less than a few megawatts each. These include four plants built in the 1940s in the Owens River Gorge, a steep canyon through a volcanic landscape north of Bishop; another four built in the early 1900s in the Owens Valley, south of Bishop (Division Creek, Cottonwood, Lone Pine, and Haiwee); and two small hydro-electric plants at the Cascades, where the Aqueduct makes its final descent into the LA basin (the San Fernando Power Plant and the Foothill Power Plant).
A large hydro-power plant on Elderberry Lake, on the north arm of Castaic Lake, north of Santa Clarita, is a source of power for DWP during peak periods of demand. The project is shared by the DWP and the State Water Project. Water flows from Pyramid Lake, an upstream reservoir on the State Water Project’s aqueduct, which brings water from Northern California. When activated, water flows out of Pyramid Lake through a 30-foot diameter tunnel, seven miles long, descending more than 1,000 feet into the turbines of the Castaic Power Plant, generating up to 1,500 megawatts. After the peak demand period ends, the turbines reverse, pumping the water back up to Pyramid Lake. Because electricity is sold at higher rates during peak demand periods, this is cost effective, even if it is not energy effective.
Around 8% of DWP electricity comes from wind, especially from the wind arrays around Tehachapi, California. Another 5-8% comes from other various sources, including biomass, landfill gas, geothermal, and solar. This amount is increasing as new generating sites come online.
Power Distribution: Receiving Stations, Converter Stations, and Switching Stations
Electricity from these sources comes via the familiar high-tension lines visible along highways and vistas in the desert around the city. They terminate at one of a few types of high voltage substations used by the DWP, which then act as a bridge between power plants and local distribution.
The principal type is called a receiving station. High voltage AC lines, typically from 115,000 volts to 230,000 volts, coming from power plants, enter the grid at receiving stations, where the voltage is stepped down to 34,500 volts or less, in long transformer banks. From there, the power is sent via underground or above-ground wires to surrounding distributing stations, which reduce the current further, to send to customers.
There are 23 receiving stations in the DWP system. Most of them are designated by a letter in the alphabet, reflecting the sequence in which they were built, and most also have a name, usually derived from a nearby street. Each receiving station has arrays of high voltage equipment in a yard larger than a few city blocks, and usually a control house facing the street, designed to reflect the architectural styles and aspirations of the time it was built.
In addition to receiving stations, there are a few switching stations in the DWP system, two DC to AC converter stations, and other control and support facilities that manage and maintain the electrical distribution network.
Distributing Stations
Powered by receiving stations, distributing stations are the last link in the high-voltage chain. They deliver their current to the community that surrounds them, usually in the form of 4,800-volt feeder lines which leave the station on top of poles, or are buried underground. The lines loop out in a vast circuit, stringing together businesses and homes, where the current is generally stepped down to 240 volts on a pole-mounted transformer.
Inside, distributing stations have transformers and racks for line wire management, including jumpers, disconnects, insulators, and breakers. They are sometimes enclosed, but more often they are roofless–their architecture really just a wall surrounding a small substation.
There are currently 123 standard distributing stations operated by DWP (and another few dozen small pole-top versions) each with a numerical designation. Most also have a name, derived from the street location, or the community they are in. The older ones look like temples of infrastructure, solid architectural fixtures facing the street. More recent ones are constructed in a style meant to blend in, intending perhaps to be unnoticed. ♦
