HVDC to LA County

The Quiet Line

You know the sound of alternating current--that sixty hertz hum that pervades the built world--it's the buzz made by old fluorescent bulbs and refrigerator compressors, and it's the crackle of corona discharge from high tension lines. Everything you plug into the wall runs on AC (unless there's a convertor in the plug, like those found on laptop and cellphone chargers). At most voltages, AC moves more efficiently through the line, and it's simple to kick the current up and down in voltage--power can leave the plant at quarter million volts, then be stepped down to the thousandth part where it comes into your neighborhood.

Direct Current is making a comeback, though--in addition to running every battery-powered device, from cellphones to Teslas, High Voltage DC can efficiently send great quantities of power over long distances at surprisingly high efficiencies. Despite the hassle of converting the power from and back to AC, HVDC can move more electricity through less wire (DC has only two poles--positive and negative--and requires only two lines. AC adds a neutral phase, necessitating a third cable. Also, for reasons I can't begin to comprehend, HVDC can literally put more current through any given piece of cable. A two-cable HVDC line can stand in for up to twelve AC cables and their attendant structures). The savings add up over long distances; the break-even point comes after about 500 miles.  

Almost all of America's electricity is consumed within 500 miles of its production; HVDC lines are quite rare. Two of the largest can be found in Southern California, connecting coastal cities to copious sources of power far inland. In a typical Southern California duality, one is benign; the other, sinister. 

The Oregon Bipole 

The Oregon Bipole (aka, the Pacific Intertie & Path 65) should be celebrated as a visionary piece of infrastructure. It supplies Los Angeles with up to 3,100 MW of cheap, clean hydroelectric power from the Columbia River. Operating at full capacity, the Oregon Bipole can supply nearly half of LA's demand. The 800 mile line enables two giant dams on the lower Columbia to power Southern California.  

The Oregon Bipole, north of Mojave, CA. The Bipole is on the left (note it only uses 2 cables) and a normal AC high tension line is on the right (3 cables)

The Oregon Bipole entering Sylmar

The Oregon Bipole runs from Celilo, Oregon (near the Columbia River) to the fabulous Sylmar Converter Station in northeast LA. In addition to housing the bipole's valve hall (where the DC is reconverted to AC), Sylmar is home to a giant conventional substation, and the massive water treatment facility next door is the downstream end of the Los Angeles Aqueduct. The city dump is literally across the road, making Sylmar the epicenter of LA's utilities. (It also smells faintly of garbage). 

HVDC lines are typically built with a 'ground return', a loose end buried in the ground a few miles from the line's terminal. If a tree falls on one cable, the buried return enables the second line to run independently (although at reduced capacity), with the earth serving as the other 'pole' for the current. The Oregon Bipole allegedly has a ground return buried in the Pacific Ocean at Will Rogers State Beach, near Malibu. I was unable to see any sign of the ground return, although the beach is quite nice on its own merits.

High tension lines surround the Sylmar convertor station in the San Fernando Valley.

The Intermountain Bipole

Southern California's other HVDC line is a sinister reflection of the Oregon Bipole. The Intermountain line connects LA to a distant and copious source inland power--but it isn't clean. This line (aka Path 27) draws its 2,400 MW's from a coalfired plant in central Utah. (not only is the coal mined in Utah, it's still legal to burn it in any quantity out there.)    

Why do I call the Intermountain Bipole sinister? Worse than the fact that it sources the dirtiest power available, the Intermountain Bipole allows LA to ignore the cost of its air conditioners--Delta, Utah is 500 miles away, and the plant's pollution will never darken coastal skies. It also enables hypocrisy on a grand scale--local activists would never tolerate a coal burning plant in the city, but the public is less interested in what happens east of the state line. In fact, the state of California burns ten times more coal in Utah than it does within its own borders--and the Intermountain plant represents only a fraction of the  imported coal power. Coal burned in New Mexico, Arizona and Nevada provides an additional 3,500 MW to the state. This allows California to pass strict emissions regulations without impacting utility rates--a convenient fraud. 

Ruin and folly. 

The Oregon Bipole is a triumph of infrastructural engineering--bringing power to the people. The Intermountain Bipole is fundamentally a piece of political engineering--sweeping the dirt far afield, it allows people to pretend consumption doesn't have its price. 

Things are looking up, though--LADWP is committed to replacing coal, and the Intermountain Bipole may one day collect its power from solar projects like Ivanpah. 

The Intermountain Bipole's ground return is easily visible just east of Barstow. The line's 'shield wires' (used to protect against lightning strikes) are repurposed for ground return between the valve hall in Adelanto and the electrodes buried in Coyote Dry Lake. Every time this segment of line is struck by lightning, the surge travels to the Coyote Lake bed, where it dissipates into the earth. From space, the return looks like a medicine wheel a half-mile in diameter; up close, it looks like a dirt road and a shed.

The Intermountain's ground return splits off from the shield wires to run the last couple miles to the buried electrodes. Note how the shield wires are insulated from the tower on the charged side.  

If You Go:

Both HVDC lines are easy to visit--the Oregon Bipole runs north along the Eastern Sierra, paralleling US 395 from Antelope Valley to Bishop. The Intermountain Bipole runs parallel to I-15 from Adelanto to Barstow. The Intermountain ground return is located at Coyote Dry Lake, east of Barstow.

They're just power lines--the only notable difference for a DC line is the lack of buzzing in its corona discharge.  (but given the proximity of conventional high tension lines, the buzz prevails anyway).

The Sylmar substation is located alongside I-5, just south of the Antelope Valley interchange. Be circumspect--LADWP is sensitive about the entire complex, and you don't want to be a nosy fellow.

Solar Ruins

Solar power, as if envisioned by Tim Burton

Labeling this site a ruin is a bit unfair--these solar-thermal units are obviously an experimental trial installation, and the companies behind the effort (IAUS and RaPower3) may eventually perfect the design. It is a brilliant concept: the 'umbrellas' are actually lenses; they are mounted on an axis that can track the sun across the sky, heating a crucible of molten sodium (which would be attached to the base of the scaffolding) to 1,300 degrees--hot enough to continue generating steam through the night.

It's brilliant, really--the design has many of the advantages of traditional solar-thermal with a far smaller footprint. On the other hand, the initial design clearly had some durability issues, and no actual generation equipment (crucibles, turbines, &c) seems to ever have been installed.

RaPower3 restarted construction last month, so perhaps they have resolved the wind issues... if you're into speculative technologies and/or creepy towers, RaPower3 is looking for investors! (they'd probably do better if their website didn't seem so scammy... also, their manufacturer, IAUS, is a penny stock with a spotty reputation... )

The wind harshed a couple lenses

Creepy. Like a dead tree or a hangman's scaffold. 

Only two towers were complete--these frames seem to have been abandoned mid-installation.

Visiting: The site is located a couple miles northwest of Delta on an unmarked gravel road. The best way to find it is to head towards the Topaz Internment Site (where we detained Japanese-Californians for the duration of WWII) and look for the posts. Right now, there's little more than a monument at Topaz (the site was razed long ago in a fit of liberal guilt), but a museum is currently under construction in town. 

The town of Delta offers all services; it's the only civilization for many miles. The nearest developed camping is at Yuba Lake. The nearest undeveloped camping is everywhere--this is the desert. 

The Military-Industrial-Recreational Complexes of the Upper Little Tennessee River

To make aluminum, start with concrete. 

The Upper Little Tennessee River--Crucible of Modernity 

The Military: Among other grizzly superlatives, World War II marked the end of the Iron Age.  For nearly 3,000 years, weapons of iron and iron alloy (like steel) had dominated warfare. Although WWII was largely fought with steel tanks, mortars, and rifles, the most lethal weapons were composed of metals unknown in premodern times: Aluminum and Uranium. 

The Industrial:Despite the prevalence of bauxite (aluminum ore) in the earth's crust, pure aluminum was unknown before the 1850's. Aluminum never occurs as a metal in nature (you won't ever stumble across a nugget of the stuff, nor pan flakes of it from a mountain stream), and it cannot be produced through chemical leaching or smelted over a flame--aluminum can only be purified through the application of copious amounts of electricity. (Although pure uranium can be produced through smelting, the resulting metal is useless for atomic purposes--separating out the useful isotope is a complex, repetitive and highly energy-intensive process).   

In the US, the machines of the 'Jet Age' and the 'Atomic Age'--synonyms for modernity itself--were largely built from metals refined in Eastern Tennessee. Neither aluminum nor uranium ore were mined in the Appalachian Mountains, and the region was certainly no center of industry or science in the early twentieth century--but ore and expertise could be imported. What was in Eastern Tennessee that could not be found elsewhere? The gorge of the Little Tennessee.  

Dangerous Waters

In 1909, the Aluminum Company of America (Alcoa) opened an aluminum smelter (the plant is called a smelter, but it operates through electrolysis) in Maryville, Tennessee. At the time, steam turbines were a new technology; massive coal-burning power plants had yet to be perfected. Hydroelectricity offered the cheapest, most reliable and most copious source of electricity, and a cheap, reliable and copious source of falling water could be found untapped in the gorge of the Little Tennessee River, upstream from the small town of Maryville, Tennessee. At the time, there was no power grid; the longest transmission line in America stretched only fifty miles. The ore would have to be brought to the power, not the other way around.

If you visit Maryville, Tennessee today, you will notice the preponderance of high tension lines.   

They're everywhere--the transmission lines in this picture alone carry enough power for 300,000 homes (Maryville-Aloca is a city of only 10,000 households) 

Follow these transmission lines out of town--they lead to a chain of mountain lakes. 

The Recreational: From its headwaters in the Smoky Mountains, the Little Tennessee River falls over 1,000 feet into the syncline of the Great Valley; it cuts a steep gorge with conveniently-spaced narrows; four dams now create a chain of lakes arranged like perfect stair-steps. Thirty miles of slack water fill the gorge; the headwaters of each reservoir back neatly up to the base of the next dam, and the entirety of the river's energy is captured inside powerhouse turbines. 

Three of these lakes--Chilhowee, Calderwood, and Cheoah (impounded by dams of the same names) are 'run-of-the-river' reservoirs--the narrow lakes follow the contours of the gorge. They are scenic, but limited area and shoreline makes these reservoirs better suited for fishing than water skiing. The massive Fontana Dam, however, creates a far larger lake on the river's headwaters. Its shoreline is almost entirely public land--the northern shore marks the edge of the Great Smoky Mountains National Park and the southern shore is largely National Forest. Hiking, boating, fishing, and wildlife watching opportunities abound. 

Fontana Dam is the tallest dam in the Eastern US (though only the twentieth-tallest in the nation). It is also notable for having been constructed during WWII, providing critical power for the production of aluminum for airplanes and the uranium used in the first atomic bombs.  

One thing Fontana is not, however, is beautiful. The dam's straight edges resemble a jersey barrier. 

Fontana Dam

A jersey barrier. 

The dam is not especially noteworthy from an engineering standpoint--aside from sheer mass, there is little that is unique to its design. It's a crowd-pleaser, though; a visitor's center on the southern rim has an impressive archive of construction memorabilia. 

It also leaks. Slowly, but enough to sustain a few plants growing from cracks in the concrete. 

A preemptive guilt trip 

An old turbine on display at the dam's base. 

Santeetla: The true engineering oddity is not far away, however. A half-mile downstream from Fontana, on the opposite shore from the highway, you will find a powerhouse... without a dam. The building's tall windows conceal its true scale--the water head (the height from which water falls to the turbines) at this site is over 600 feet--if there were a dam here, it would be America's fifth tallest.   

But there is no dam. Just a tank. Surely that can't be the reservoir!

It is not unusual to see a powerhouse removed from its dam--many early hydro plants used a diversion flume to bring water further downstream, increasing the head height. These turbines, however, are not fed by a flume running from Fontana Lake.  In fact, the powerhouse predates the Fontana Dam by twenty years.  

You can drive up to the tank (Rhymer's Ferry is your road for this); if you do, you will find that no open flume, creek or pond fills the tank.

Follow that pipe!

Instead, it's a sealed pipe a dozen feet in diameter. The pipeline runs aboveground for a short distance, then disappears into the mountain; a few miles to the south, the pipeline emerges again near Yellow Creek Road for a couple hundred yards.

Pipeline crossing the Yellow Creek Valley 

It's easy to spot.

Note that this pipeline isn't headed upstream--the route leaves the Little Tennessee Valley entirely and crosses a ridge, moving perpendicular to the river. The next time the pipeline appears, it crosses the Cheoah River.  The river itself has been reduced to a trickle, just enough to dampen the riverbed. Where does all the water go? It's in the pipe, of course. 

The final nine miles of the Cheoah River is diverted through this pipe--1,000 cubic feet of water per second; given the pipe's diameter, that means the current inside is flowing at around 7mph--as fast as a typical Class IV rapid. Where the river crosses itself, the pipeline is actually a siphon, with the suction of water in the 'downstream' portion pulling the current up the opposite bank.      

Imagine a whitewater rapid, charging uphill--that's what's happening inside this siphon!

Crossing the highway for scale. 

End of the line--the pipeline emerges from Santeetla Dam. 

Diverting a river across a divide to a powerhouse located an entirely different watershed is unusual, even unprecedented. (Numerous other diversion dams exist, of course; many channel water across divides--but always for irrigation, not hydropower. Long flumes or sluices are also common in early hydro projects; however, other sluices follow the course of the impounded river and eventually drop the water back into the original watershed.)  

The Santeetla Dam is a prime example of the High Imperial Mayan style of architecture. Note how the spillways resemble pyramids and the concrete is weathered to a streaked brown patina.

The fecundity of the surrounding forest adds to the dam's 'jungle ruins' aspect.    

Which begs the question: why here? A quirk of geography, of course.

Damming the Choah River proved problematic: The best available site was located nine miles upstream from its confluence with the Little Tennessee--building a dam here would mean ceding 500 vertical feet of the river's course (around 200 MW worth of potential power). Unacceptable.

Building a lower dam, however, would be impossible--the gorge is too wide at its base, and the lack of a high wall also precluded a downstream flume (to be effective, the headstock must fall nearly straight down--a sloping flume loses power to friction).  

So this is the ingenious solution Alcoa's engineers engineered--if the dam could not be built at the edge of slack water, the Cheoah must be brought to the slack water. Siphoning the Cheoah across the divide and dropping the water into the Little Tennessee not only enables a 230 foot dam to generate power from a water head 600 feet high, it also allows that water to pass through a second set of generators at Cheoah Dam (on the Little Tennessee upstream of the confluence).     

Visiting: The Military-Industrial-Recreational Complexes of the Upper Little Tennessee are located about twenty miles east of the town of Maryville, Tennessee on Highway 129. Here's a map. All services can be found in Maryville as well as Robbinsville, NC, located between the Fontana and Santeetla Lakes.  

Free campsites are available on the shore of Santeela Lake, and numerous campgrounds are located throughout the surrounding National Forest and GSMNP. Boats can be launched and rented at both lakes, and superlative hiking trails run through both the Great Smoky Mountains and the Joyce Kilmer Forest. 

Summer is the best time to visit, but winter snowfalls are infrequent and short-lived. When driving on Route 129, be aware that this twisting highway, known as the "Dragon's Tail" is popular among motorcyclists and you will encounter riders displaying a broad spectrum of skill and judgement.