Built to power the growing Red Electric Streetcar transportation system in Los Angeles, the 12-MW Borel facility continues operating today, providing a reliable supply of electricity within California. Borel is one of three plants to be inducted into the Hydro Hall of Fame in 2011.
By Tobin L. Gibson and Brian McGurty
Every hydro facility built at the turn of the 20th century has unique stories to tell, and 12-MW Borel is no exception. This project was built to provide power for the growing Red Electric Streetcar (also known as Red Car) transportation system in Los Angeles. In addition, electricity from Borel was transmitted using steel towers, which proved this material would not adversely affect long-distance transmission.
But the unique stories did not end once the plant began operating. In the early 1950s, the U.S. Army Corps of Engineers built Isabella Dam just 6 miles upstream of Borel to provide flood control. Amazingly, Southern California Edison was able to keep the Borel facility operating during this construction, thanks to a spirit of partnership and cooperation with the Corps. Learn more about the historic Borel powerhouse, the most recent inductee into the Hydro Hall of Fame.
Understanding the development
Hydroelectric development on the Kern River in central California began in 1894 when the Power, Transit and Light Company started construction of a small plant at the mouth of Kern Canyon. The following year, the Kern River and Los Angeles Electric Power Company obtained water rights on the river and planned construction of a power plant, but the company was unable to finance the project. In 1987, the PT&L plant began operating. That same year, Kern River and Los Angeles Electric Power began to undertake just enough work on a canal to retain its water rights on the river.
This continued until 1902, when Henry E. Huntington and partners formed the Pacific Light and Power Company. Huntington had purchased the narrow gauge, city oriented Los Angeles railway, known as the Yellow Electric Streetcars or Yellow Car system, in 1898. In 1901, he formed the standard gauge Pacific Electric Railway, known as the Red Car system, by consolidating many smaller railroads. The Red Car system provided mass transit in southern California, organized around two nexuses located in the city centers of Los Angeles and San Bernadino. The system shared some dual gauge track with the Yellow Car system.
PL&P needed electric energy to power Huntington’s growing streetcar system. Construction of the Borel facility provided the first opportunity available to import that power using available transmission lines. PL&P purchased the Kern River and Los Angeles Electric Power stock, reconstituted the company as a subsidiary named the Kern River Company, and quickly moved forward on construction of the long-delayed hydro plant.
The resulting 10-MW plant, named Borel for Huntington’s business partner and San Francisco financier Antoine Borel, was completed in 1904.
Materials needed to construct the facility were transported using 20-mule teams across rough terrain and up steep, narrow mountain roads carved out with picks and shovels. Concrete was hauled to the site by wagon teams from Tehachapi, about 45 miles away. Loads of machinery were brought across the rugged country from the railhead at Caliente, nearly 40 miles away. Smaller teams of six mules or horses were used to pull the plows and scrapers that formed the canal bed. Because the roads were narrow, the animals had to be harnessed two abreast, instead of the more traditional method of having four or more animals abreast.
Villages sprouted up around the plant, where workers raised their families. These houses later were occupied by operators and hydrographers working at Borel.
A 12-mile-long flowline transported water from the north fork of the Kern River to the powerhouse. This flowline consisted of a 50-foot-wide by 10-foot deep unlined (dirt) canal and several flumes where the flowline needed to cross a creek or ravine.
One such flume was the Bodfish flume, which passed over the town of Bodfish, 3 miles west of the Borel powerhouse. The original flume, built in the 1890s, was a wooden girder structure. In 1927, the Bodfish flume consisted of a 57-foot-high steel-braced frame and truss structure with a total span of 630 feet. It supported an open, catenary-shaped sheet metal flume 19 feet wide at the top and 9 feet deep. (A catenary is a symmetrical curve that is identical to the graph of a hyperbolic cosine.) The Bodfish flume had a carrying capacity of about 620 cubic feet per second.
|As this historical photograph shows, the Borel powerhouse originally contained five horizontal turbine- generating units.|
The water conduit at Borel has an unusually low grade of only 1 foot per mile, equating to a slope of only 0.0189 percent. SCE personnel speculate this low canal gradient was a cost-benefit tradeoff. Choosing this grade allowed the developer to get maximum possible head at the plant while still using gravity to transport the water through the canal. The plant has a head of about 230 feet of head, and water was fed to the powerhouse via five 438-foot-long, 60-inch-diameter penstocks.
Power was generated by five horizontal reaction-type turbine-generator units.
Electricity from Borel was transmitted at 55,000 volts over a 127-mile-long transmission line to Los Angeles. The line was the first to use steel towers and proved these towers would not adversely affect the long- distance transmission of electricity, which was a concern at that time.
Changes over time
In 1908, Kern River Co. was absorbed into PL&P, and in 1917 PL&P merged with SCE.
When Borel was built, Huntington had been investing heavily in real estate in southern California. Therefore, the plant was built on a tight budget and many corners were cut. As a result, the project quickly underwent major repairs and reconstruction. For example, in 1912, all five of the turbines at Borel were reconstructed. A historical photo on file with SCE shows that at least one turbine scroll case was hauled to the site via a wagon pulled by an 18-mule team.
Some time in the late 1920s to early 1930s, one unit was removed from the Borel plant, as was the corresponding penstock. SCE personnel can only speculate on this situation, as they have been unable to find documentation indicating what happened. One possible scenario may have been that the amount of water available in canal was not sufficient to spin five turbines. Or, one of the original five units may have been a standby unit, meaning the developers intentionally overbuilt the powerhouse to have an extra unit available during repairs.
Not long after that (likely in the early 1930s), the number of units in the plant dropped again, to three, although four penstocks remained. The unit that SCE personnel believe replaced two of the original turbines at Borel is a single, larger vertical reaction unit. The third and fourth penstocks now join to supply this Unit 3.
Borel became the first of SCE’s generating stations to become unattended when it was placed into semi-automatic operation mode in 1947. However, the facility remained manned during the daytime until normal attrition of personnel occurred in 1957.
Borel is the only plant in the SCE hydro system for which the company forgoes its water entitlements. This allows the San Joaquin Valley farmers to store irrigation water in Isabella Reservoir, for which SCE is compensated. SCE renews this agreement annually, depending on the amount of precipitation.
|The Borel powerhouse, on the Kern River in California, was built to provide power for the Red Electric Streetcar transportation system in Los Angeles.|
In 1948, Congress appropriated funds to build a dam to prevent flooding of Bakersfield, Calif. The city had been flooded in 1867 and 1893. In 1950, while Isabella Dam was being built 7 miles above Borel, flooding measuring 30,000 cubic feet of water per second occurred. Because construction of Isabella Dam would bisect the Borel canal, the Corps entered into an agreement with SCE such that the dam would be built in a manner to “afford operation conditions at least equal to that existing in the Borel Canal under pre-project [pre-Isabella Dam] conditions.” That 1950 Contract for Relocation, Rearrangement, and Alteration of Borel Facilities requires that the Corps make available to the Borel project the full flow of the Kern River and all releases from storage in Isabella Reservoir. In addition, the Corps must operate and maintain Isabella Dam and reservoir in a manner that will not interfere with or otherwise reduce the efficiency or capacity of the operation of the Borel project.
The Corps completed construction of the dam in March 1953, and, as anticipated, the dam flooded Kern Valley and inundated the upper 6 miles of the canal conveying water to the Borel powerhouse. The solution the Corps negotiated with SCE involved rebuilding the diversion structure, canal and trestles within the inundation zone using concrete; replacing the trestle across the main fork of the Kern River with a siphon; and constructing the Lake Isabella Auxiliary Dam as the Borel intake, except when the lake is below the level of the canal.
Although the lake is quite large at about 568,000 acre-feet, its practical storage limits prevent it from being filled most of the time. These limits resulted from the requirement to protect endangered species riparian habitat and, in more recent years, self-imposed restrictions because of seismic and seepage concerns that are being investigated. The lake is subject to flood control operation and water supply for the San Joaquin Valley. More than half of the time, the runoff is less than the statistical average. A sequence of several dry years in a row or one or two extremely dry years results in the lake level dropping below the auxiliary dam intake gates, which the Corps operates to supply water to Borel.
At this time, SCE and the Corps must work together to clean up and activate the original canal section and intake on the north fork of the Kern River to maintain water flow from the river to the plant. This work requires three to four months, depending on the amount of repairs needed. The Corps estimates that the work to clean out the intake structure, for which it is contractually obligated, will cost several to many millions of dollars the next time the intake is exposed. Water then follows the old canal to the auxiliary dam, where it flows through a tunnel and continues downstream to the Borel powerhouse.
In 1954, a separate agreement was made between SCE and the Kern River Watermaster and associated downstream agricultural water districts to further guarantee SCE’s continuing right to the full operation of the Borel Canal. It is the Kern River Watermaster who schedules the releases from the Isabella Reservoir, once the annual flood control rule curves have been factored in.
During the restructuring of California’s electricity industry in the late 1990s, SCE sold most of its generating facilities, retaining only its hydro, coal and nuclear plants.
The Bodfish flume, which many referred to as a landmark, was dismantled in 1997 because of seismic concerns and frequent leakage. Structural evaluations conducted in the 1990s revealed the flume would be at risk of failing during an earthquake, with a potential transverse displacement of about 1 foot. This section of the flowline was replaced with a11-foot-diameter steel pipe, with a siphon configuration, buried in a 20-foot-deep trench.
|The Borel powerhouse continues to operate successfully after more than 100 years, providing a reliable supply of electricity to the California transmission system.|
In 2004, SCE celebrated the 100th anniversary of operation at Borel with a luncheon, tours, and speeches. Attendees included Borel employees and retirees, SCE representatives and local dignitaries. Among those in attendance was retired SCE chief plant operator Harvey Malone, who worked at Borel in 1947.
In October 2010, SCE began work on two significant rehabilitation projects.
One was a rehab of the Borel forebay. The old forebay structure featured a wood deck and stairs and home-built trashracks and trashrakes. In addition, a significant amount of moss grows in the canal, which sheds onto the trashracks and cuts down on flow to the plant. The old method of dealing with this involved personnel using pitchforks to load the moss into wheelbarrows for transportation and disposal. The rehabilitation, performed by a contractor, involved adding motorized actuators to the penstock gates, redesigning the spillway on the forebay side, and installing new trashracks and trashrakes and a conveyor system.
The second was a switchyard rehab, also performed by a contractor. The single transformer bank was 70 years old, with four single-phase transformers (three in service and one as a spare). These were replaced with a single three-phase transformer bank, and all the 69-kV oil-filled circuit breakers were replaced with SF6 gas type breakers. This work primarily was performed to be environmentally sensitive and remove any oil near the river.
Work on both of these rehab projects was completed in March 2011.
The powerhouse has three generating units and four penstocks and a total rated capacity of 12 MW. Borel is located on public land within the Sequoia National Forest.
Today, the company provides power to nearly 14 million people in a 50,000-square-mile service area. In 2010, SCE provided 19.4 percent of its total power deliveries to its customers from alternate and renewable energy sources, including small hydro, geothermal, wind, solar and biomass. SCE owns large hydro facilities, such as the 865-MW Big Creek system in the Sierra Nevada foothills and mountains east of Fresno, Calif. The company also owns the gas-fired combined cycle Mountainview plant and owns 79 percent of the San Onofre Nuclear Generating Station in San Clemente, Calif.
Hydroelectric facilities provide a variety of unique benefits, among which are the fact that it is the most cost- and energy-conversion-efficient of all current sources of power, that it is used to stabilize the transmission grid, and that it leaves behind no waste. The Borel powerhouse in particular provides hydropower needed to meet the mandatory California renewable portfolio standard, by which SCE is obligated to produce or purchase a specified faction of its electricity from renewable energy sources and for which the “premium” cost to SCE’s ratepayers to replace hydropower from Borel would be twice the normal market clearing price.
The next major work to be performed at Borel is a control room rehab. A new automation system is to be installed. The time frame for this work is being coordinated with Corps efforts to modify the Lake Isabella auxiliary dam from which SCE gets the water for Borel. The Corps must shut off water to canal during this work. SCE and the Corps are trying to coordinate efforts and looking at a 2014-2015 time frame. During this work, the Corps will make the required instream flow releases for the Borel facility.
Toby Gibson is Kern River manager and Brian McGurty is project manager with Southern California Edison’s hydro division.