Getting Pumped: How LA Uses Two Big Lakes to Store Energy like a Giant Battery

LOS ANGELES – If L.A. is going to stop burning fossil fuels by 2045 — a key goal of Mayor Eric Garcetti’s proposed Green New Deal — it must store a lot more of the excess solar and wind energy it produces during the day so it doesn’t have to rely on gas and coal energy to power the city when the sun sets and the wind dies.

There’s a growing focus on building big batteries — for example, the kind that use lithium ions. But L.A. needs energy storage that is far bigger than any traditional battery.

And it’s found one.

The Los Angeles Department of Water and Power has turned two big lakes into a monster battery capable of storing enough energy to power tens of thousands of homes.

It involves using the excess wind and solar power L.A.’s renewable energy sites produce during the day to pump water from Castaic Lake uphill 7.5 miles to Pyramid Lake. Then, late in the day, when the sun goes down and the city’s energy demand spikes, the water gets run downhill through hydroelectric generators at Castaic Lake.

The next day, the cycle starts over again. The same 10,000 acre-feet of water can recirculate over and over, getting pumped uphill during the day and coming downhill at night to power the city.

It’s called pumped storage, and the plant at Castaic is one of the largest such plants in the western United States, but maybe not for long.

LADWP is looking at building an even larger plant at Hoover Dam, so this form of energy storage, if replicated, could be a key to L.A. weaning itself off of fossil fuels.

So Let’s Tour the Castaic Pumped Storage Plant

It’s hidden away — kind of like a superhero’s secret lair — behind locked gates at the end of a winding mountain ridge road off I-5.

Castaic Pumped Storage Plant as seen from a mountain ridge near Ridge Route Road. (Photo by Sharon McNary/KPCC/LAist)

Once you’re inside the gates, the first thing you notice are six gargantuan pipes that flow water from Pyramid Lake 7.5 miles down to Castaic Lake. Water is pumped back uphill in the same 30-foot-diameter pipes.

The pressure is 25 times the force of the water coming out of your home faucet.

Here’s another look at those massive pipes from a different perspective, way up on the mountain looking down at Castaic Lake.

These massive pipes, called penstocks, move water up and down between Castaic and Pyramid Lakes. This is a view looking downhill at Castaic Lake. The Elderberry Forebay at the base of the pipes is part of Castaic Lake. It holds up to 10,000 acre-feet of water that can be recirculated between the two lakes. (Photo by Andrew Cullen for LAist)

Time to head down into the guts of the plant. We step off the elevator to a balcony overlooking a giant windowless chamber four stories tall.

The six turbines are in a vast windowless chamber. The pressure of the water coming downhill in the giant pipes spins the hydroelectric turbines, generating power for Los Angeles. More than 50 LADWP employees keep the plant running.

Below you can see two of the six turbine units. Unit 3 on the left, is covered and is ready to produce electricity as water spins the turbines inside it. Unit 4, on the right, is open for maintenance.

Unit 3, left, produces electricity while Unit 4 sits open for maintenance at Castaic Hydroelectric Power Plant in Castaic, Calif. (Photo by Andrew Cullen for LAist)

The six turbine units look like giant spools sunk into the floor. They put out enough energy, when they are all spinning, to power 83,000 homes over the course of a day. Their output is huge in comparison to LADWP’s largest chemical battery, which is a 20 megawatt lithium ion battery, which can power about 600 homes over a day.

Here is a view of the turbine in Unit 5. It’s been lifted partially above the floor of the turbine room. Each turbine weighs 550 tons. To lift them up takes two cranes that move the length of the room.

Castaic Hydroelectric Power Plant has six reversible 250,000 kilowatt turbines. The plant provides power for Los Angeles during peak use periods. (Photo by Andrew Cullen for LAist)

It takes a lot of pipes and plumbing to control the flow of water in this pumped storage plant. We descend several flights of stairs to get to the bottom of the plant to see the pumps.

At the very bottom of the plant, we’re 90 feet under the water level of the lake.

Massive machinery controls the flow of water through the hydroeletric plant at Castaic Hydroelectric Power Plant in Castaic, Calif. (Photo by Andrew Cullen for LAist)

The pumps are what makes this plant different from an ordinary hydroelectric plant. There are six giant pumps — each with a shiny silver piston arm. They are pushing water back up the mountain to Pyramid Lake in the same 30-foot-diameter pipes that brought it down to Castaic Lake.

Recirculating the water like this takes a lot of energy — but that’s okay. DWP has more wind and solar energy during the day than it can use. So rather than disconnect the solar panels and windmills, or sell the energy cheaply to someone else, DWP uses the extra energy to move the water uphill to Pyramid Lake.

Once the water is waiting uphill at Pyramid Lake, it’s stored energy, ready to flow back downhill to generate energy when L.A. needs it, late in the day.

A pump pulls water from 90 feet under Lake Castaic into the Castaic Hydroelectric Power Plant in Castaic, Calif., and sends it uphill to Pyramid Lake. (Photo by Andrew Cullen for LAist)

This battery-like combination — pumps and turbines — can be built very big. And they use the most reliable force on Earth — gravity.

Elderberry Forebay is a section of Castaic Lake that holds the water that gets recirculated between Pyramid Lake and Castaic to produce electricity.

Runoff from Castaic Hydroelectric Power Plant enters Elderberry Lake, which holds water that can be pumped back up to Pyramid Lake and reused to produce electricity. (Photo by Andrew Cullen for LAist)

Assistant general manager Reiko Kerr says they could pump water from Lake Mohave 20-some miles upstream to Lake Mead to run through Hoover Dam’s giant hydroelectric turbines.

“You already have the dam, you have the generators, you have the transmission lines — you basically need a set of pumps and pipelines,” Kerr said.

The eventual size depends on the number of other agencies that might invest in the project.

“That upper reservoir is huge — Lake Mead — so you could store power in the form of water up there for potentially months, and seasonally,” she said.

The Hoover Dam pumped storage project could come online by 2030, adding to the energy storage L.A. needs to get to 100% renewable energy.

The Irony of an Electric Car Named ‘Tesla’

Thomas Edison became a household name for inventing the first practical incandescent light bulb. But because of what happened in a small town in Colorado, his bitter rival Nikola Tesla won the bigger prize to electrify our modern grid. Over a century later, could revenge be in the offing?

DENVER – In the late 1800s there was a battle raging. It wasn’t over territory, ideology, or settling old grudges. It was a clash over how we—and for that matter the world—were going to get our energy. Although the ability to generate electricity had been established, just how to deliver it to the masses—primarily for the purpose of lighting—was still unanswered. It was a contest that about a century later inspired a rock band to name itself “AC/DC.”

The “War of the Currents” as it was called was between Thomas Edison, who backed direct current or DC, and Nikola Tesla, who was promoting something different—alternating current or AC.

Without getting too far into the weeds, the main difference between the two is the way the electrons move. DC travels in only one direction and is the electricity that comes from batteries. AC reverses direction at regular intervals and is generated by moving a magnet through a coil of wire. But one of the most important differences at the time was that AC could be transmitted long distances—an advantage that would prove decisive.

Suffice it to say there was a lot at stake over which system was going to electrify the nation, and at times it got a bit ugly with Edison launching a propaganda campaign — what today we might call “fake news”—by doing things like electrocuting animals with AC to try to prove its dangers. Tesla meanwhile had teamed up with entrepreneur George Westinghouse, who saw electrification as an enormous business opportunity and had purchased Tesla’s patents.

This high stakes war ended with a victory in, of all places, Telluride, in southwest Colorado. Back around 1885, mines were a huge industry in the state, but they were starting to fail because they lacked a power source to operate. Nearby forests had been cleared for fuel and the cost to bring in coal by burros was too expensive. The Gold King mine above Telluride (not to be confused with a mine of the same name near Durango, which had the devastating spill into the Animas River a few years ago), had a lot of ore left in it, but production costs were getting too high to make it feasible.

The Telluride mine also had a river nearby — a fork of the San Miguel. A man named Lucien L. Nunn, who was a major investor at the time, thought it would be a perfect source of hydropower—if only they could get the electricity transmitted the two miles up the mountain to the mine. So Nunn approached Westinghouse to try out Tesla’s idea for alternating current.

Interior view (c.1900) of Ames powerhouse showing switchboard on left and generator on right. (Public Domain)

Tesla himself did not come to Telluride. Westinghouse sent a team of engineers to Colorado to build the Ames Hydroelectric Plant based on his designs for the generator and induction motor. On the 19th of June 1891, they flipped the switch and sent electricity along newly constructed transmission lines up to the Gold King, which was at 12,000 feet in elevation. The engineers were so amazed—and nervous that it worked—that they didn’t turn it off for thirty days. When they did turn it off—and turned it back on—it continued to work, and the Ames plant made history as the first hydroelectric facility to generate and transmit alternating current for industrial purposes in the U.S. The success at Ames proved that AC was a viable option, and, shortly after, the same design of the plant was built on a much larger scale at Niagara Falls.

Lucien Nunn went on to install similar systems at other mines and eventually provided electricity to Telluride—making it the first town in the country to be powered by alternating current. The Ames hydro plant runs to this day and is owned and operated by Xcel Energy. Mychal Raynes, a plant specialist, says it’s only needed a few improvements and otherwise is still using the original equipment.

Directly Back to the Future?

So the rest was history and alternating current won. Or did it?

As Stephen Frank, a research engineer with the National Renewable Energy Laboratory (NREL) near Golden, Colorado, explains, a home built in the 1950s would probably have all its fixtures and appliances running on alternating current. But that all changed with the advent of the transistor in the 1950s, which opened the door for power electronics that help convert electricity for use in numerous devices we use today. Pretty much everything in a modern home—from computers and televisions to lights and washing machines—are all using direct current because of the electronics inside. That white cube that plugs into the wall to charge your phone? It’s a power electronic converting AC to DC.

But every time these conversions happen energy is lost in the form of heat—something undesirable in the middle of summer. And given that you might use an air conditioner to cool down a building warming up from multiple appliances, conversions are wasting electricity.

So because our infrastructure is still running on AC but a lot of end-use or “load” is DC, Frank and his colleagues are doing much research on direct current technology to save energy, especially in buildings. In the aggregate, Frank says, “we’re talking about maybe being able to save 5-10 percent of all of the electricity that we consume in this country. We’re talking about roughly the amount of electricity that the state of Oregon uses in a year.”

Changing the grid itself is not something that would happen in the near term, but finding places to increase efficiency is the focus of much research. However, right now if someone wanted to design a new building to run completely on direct current, it would be challenging because they can’t go down to a home improvement store and pick up a DC outlet. The marketplace isn’t there yet. Frank says in order for there to be a change, standards need to be developed about everything from the shape of outlets to how to reuse AC wiring.

The bottom line about whether DC is the right choice for a new building Frank says, depends on a lot of factors: the availability of products, electricity rates, and capital cost of the equipment—many factors that don’t have anything to do with efficiency difference between the two systems. All factors have to be considered in order to make an informed choice about which system is best on a case-by-case basis.

But there may be a very compelling reason to incorporate more direct current into the grid—the surging sales of electric vehicles (EVs) that need charging stations for their batteries.

“Vehicle diversification is happening rapidly,” says Greg Martin, an electrical engineer who works at the energy systems integration facility at NREL, and that raises several questions: What is the impact to the grid? Where does it make sense to do the conversion to DC? If you want to rapidly charge your car in five minutes you really want to be hooked up to a DC charging system. Martin adds that in light of trends in transportation there’s a question about to what extent do we want to generate and distribute DC to support it. “These are topics in research right now as we speak.”

The ubiquity of power electronics and the trend toward EVs is a twist that should make fans of Edison smile—if not feel some vindication. As Frank says wryly, “I find it deeply ironic that an electric car using battery storage and charging with fast DC chargers has Tesla’s name on it.”

This article was first published by on March 22, 2019, and is republished with permission. You can find the original article here.

Utilities scramble to replace power poles, water pipes in wake of California wildfires

MALIBU, Calif. – The recent California wildfires have destroyed far more than homes. Wooden power poles, PVC water pipes and water mains all are taking a beating. So utility workers now are scouring scorched terrain across the state to return everything to working order, which takes a great deal of effort and resources.

Southern California Edison is one of the biggest utilities in the U.S., providing service to 15 million people in central and Southern California.

Edison’s fire management officer, Troy Whitman, said the utility has more than 500 workers dedicated to recovery in the Malibu area, and the number is only growing: “It really takes a small army to support the operation.”

When a wildfire hits, Edison handles it in three phases:

Emergency response, when workers clear out any hazards so evacuees and officials can get where they need to go quickly.
Damage assessment, which means driving (and in some cases, helicoptering) around to see what’s broken.
Restoration, which is the process of replacing everything that was damaged.

Because the fires are still burning, utilities haven’t finished finding what needs fixing. But so far, Edison needs to replace roughly a thousand power poles in Malibu alone, and most of the high-voltage wires they carry.

But it turns out not all poles are created equal.

“Each one of these pole locations has to be engineered for the pole height and the pole strength,” Whitman said. “All of the equipment and hardware on each pole is specific to that location, so packages are created for each one of those locations.”

Fixing the poles along the Pacific Coast Highway and the major canyons is as easy as driving up to where they fell. But in some of Malibu’s smaller, more winding roads, it means digging into the ground by hand, then using a helicopter to set the pole in place.

Whitman said Edison has been using wire with new insulation, which will be less likely to spark when a pole falls down or when debris hits the wire. That could mean fewer fires.

“You can touch it with your hand and you’re insulated from the electricity flowing through the wire,” he said.

Southern California Edison says it has more than 500 workers dedicated to recovery in the Malibu area, and more will be needed. (Photo by Caleigh Wells/LAist)


Using all that water for fighting wildfires stresses local water systems, too. In the water district north of Malibu, about two-thirds of its service area burned, which overwhelmed the district’s resource, said Dave Pederson, general manager of Las Virgenes Municipal Water District.

“Public water systems are not designed to fight wildfires, they’re designed primarily for a structure fire, and to meet people’s domestic and home needs,” he said. “The system does its best to accommodate the firefighting efforts put on the system, but it can only do so much.”

It resulted in warnings to some residents to boil water because bacteria may have leached into the system.

But that wasn’t just because of the high demand from firefighters as they diverted water to their hoses. The fire also melted PVC pipes and broke water mains, and when the power went out, it shut down the pumps that move the water.

“Normally when there’s a leak in a water system … the only thing that happens is the water leaks out so the system is really safe from contamination,” Pedersen said.

But with the drop in pressure from so many demands, contaminates could leak in wherever the pipes were broken. Hence the notice to boil water (which was lifted Friday, Nov. 16).


Whitman said that, 25 years into his job, he sees the fires getting worse, so it’s a good time for safer power lines.

“The last few years, everyone has seen the increase in fire activity, the rate of spread of these fires, the devastation. I see in my job that things are changing.”

As for an end date, Whitman said the extent of the damage still hasn’t been determined because crews still aren’t able to get to some parts of Malibu.

“But we’re working feverishly to replace the poles we do know about.”

Tribally owned solar power plant beats skeptics, set to expand on Navajo Nation

WASHINGTON – Deenise Becenti remembers watching this summer awhile a woman in the Navajo Nation who had been waiting more than 20 years to get electricity in her home flipped the switch to turn on the lights for the first time.

“She had a whole lot of happy tears,” said Becenti, the spokeswoman for the Navajo Tribal Utility Authority. “It was a very humble day because you knew that she had been waiting for ‘the day’ for a very long time.”

“The day” was made possible by the Kayenta Solar Project, the first large-scale solar farm on the Navajo Nation and the largest tribally owned renewable power plant in the country. The 27.3-megawatt plant, which went on line last summer, now generates enough power for 18,000 homes on Navajo lands.

The path to this moment was not an easy one.

For years, there had been talk about supplying renewable energy to homes on the Navajo Nation, but that’s all it had been – talk. When NTUA General Manager Walter Haase first proposed that the tribe build its own solar-generating plant, there were skeptics.

When Haase began his job at NTUA in 2008, there were about 18,000 homes without electricity. The utility was in the red. It had never owned its own generating facility. And Haase, who is not a member of the tribe, had to gain the trust of the Navajo people and their government.

“They had moved off the nation to cities … because they (cities) had electricity. So now that the … area is connected, they said, ‘OK,’ and have moved back.”

Deenise Becenti, spokeswoman for the Navajo Tribal Utility Authority

“We were in the red, and we just had no direction,” before Haase took over, Becenti said. “The leadership was not there, so he was able to completely turn this enterprise around.”

The idea for Kayenta came together in 2014 and the NTUA was able to break ground two years later. It went online in September, 2017. And, just a few months later, in January of 2018, an agreement was reached to double the size of the project, calling it Kayenta II. Construction for the expansion breaks ground at the end of August.

The project created as many as 284 construction jobs in an area with chronically high unemployment – and facing the possible loss of thousands of jobs with the looming closure of the coal-fired Navajo Generating Station and the nearby Kayenta Mine that keeps it stocked with coal. Haase said that 85 percent of the workforce on the solar project were of Navajo descent.

“We need folks like Walter who are going to be persistent and say that there is no opportunity that is too difficult to deploy this important technology and all the benefits that come with it,” said Tanuj Deora, chief strategy officer with the Smart Electric Power Alliance.

Deora, whose organization recognized Haase as its Visionary of the Year this summer, said completion of the Kayenta project proves that the Navajo Nation is ready to take on other large-scale renewable energy development.

And Haase said the project has generated more than electricity for the Navajo – by owning and operating the plant, the tribe has gained a new source of revenue.

“It’s significant dollars back to the Navajo Nation government, which needs that to provide self-sustaining … services to their people,” Haase said.

The Kayenta Solar project created as many as 284 construction jobs while it was being built, in an area with chronically high unemployment. It opened last year and plans are already underway for a second phase, with groundbreaking set for later this month. (Photo courtesy Navajo Tribal Utility Authority)

Becenti said that the first phase of the solar project has brought families back together on the reservation.

“They had moved off the nation to cities … because they (cities) had electricity,” Becenti said. “So now that the … area is connected, they said, ‘OK,’ and have moved back.”

Becenti nominated Haase for the SEPA award that honors someone who pursues projects “that promote collaborative, innovative and replicable models for change” and that “significantly advance knowledge of or access to distributed energy resources.”

“I already knew I would submit his name for consideration because he’s brought significant progress to the Navajo Nation,” Becenti said of the award, which was presented last month.

There are still challenges. The number of homes off the grid has improved since Haase started, but still stands at roughly 15,000, Becenti said. Although Kayenta could power up to 18,000 homes, getting them connected to the plant is still a challenge because of the vast distances on the remote reservation.

But Becenti looks to the positives.

“We’re meeting the needs of our people … and certainly meeting the definition for which we were created, which was to meet the growing utility demands of the Navajo Nation,” Becenti said.