San Francisco Chronicle - (Sunday)
$3 billion plan to turn Hoover Dam into a giant battery
Hoover Dam helped transform the American West, harnessing the force of the Colorado River — along with millions of cubic feet of concrete and tens of millions of pounds of steel — to power millions of homes and businesses. It was one of the great engineering feats of the 20th century.
Now it is the focus of a distinctly 21st century challenge: turning the dam into a vast reservoir of excess electricity, fed by the solar farms and wind turbines that represent the power sources of the future.
The Los Angeles Department of Water and Power, an original operator of the dam when it was erected in the 1930s, wants to equip it with a $3 billion pipeline and a pump station powered by solar and wind energy. The pump station, downstream, would help regulate the water flow through the dam’s generators, sending water back to the top to help manage electricity at times of peak demand.
The net result would be a kind of energy storage — performing much the same function as the giant lithium-ion batteries being developed to absorb and release power. The Hoover Dam project may help answer a looming question for the energy industry: how to come up with affordable and efficient power storage, which is seen as the key to transforming the industry and helping curb carbon emissions.
Because the sun does not always shine, and winds can be inconsistent, power companies look for ways to bank the electricity generated from those sources for use when their output slacks off. Otherwise, they have to fire up fossil-fuel plants to meet periods of high demand.
And when solar and wind farms produce more electricity than is needed, California utilities have had to find ways to get rid of it — including giving it away to other states — or risk overloading the electric grid and causing blackouts.
“I think we have to look at this as a once-in-acentury moment,” said Los Angeles Mayor Eric Garcetti. “So far, it looks really possible. It looks sustainable, and it looks clean.”
The target for completion is 2028, and some say the effort could inspire similar innovations at other dams. Enhancing energy storage could also affect plans for billions of dollars in wind projects being proposed by billionaires Warren Buffett and Philip Anschutz.
But the proposal will have to contend with political hurdles, including environmental concerns and the interests of those who use the river for drinking, recreation and services.
In Bullhead City, Ariz., and Laughlin, Nev. — sister cities on opposite sides of the Colorado, about 90 miles south of the dam — water levels along certain stretches depend on when dams open and close, and some residents see a change in its flow as a disruption, if not a threat.
“Any idea like this has to pass much more than engineering feasibility,” said Peter Gleick, cofounder of the Pacific Institute, a think tank in Oakland, and a member of the National Academy of Sciences, known for his work on climate issues. “It has to be environmentally, politically and economically vetted, and that’s likely to prove to be the real problem.” Using Hoover Dam to help manage the electricity grid has been mentioned informally over the past 15 years. But no one pursued the idea seriously until about a year ago, as California began grappling with the need to better manage its soaring alternative-electricity production, part of weaning itself from coal-fired and nuclear power plants.
In California, by far the leading state in solar power production, that has sometimes meant paying other states to take excess electricity. Companies like Tesla have entered the picture, making lithium-ion batteries that are used by some utilities, but that form of storage generally remains pricey.
Lazard Asset Management has estimated that utility-scale lithium-ion batteries cost 26 cents per kilowatt-hour, compared with 15 cents for a pumped-storage hydroelectric project. The typical household pays about 12.5 cents per kilowatthour for electricity.
Los Angeles operates a hydroelectric plant at Pyramid Lake, about 50 miles northwest of the city, that stores energy by using the electric grid to spin a turbine backward and pump water back into the lake.
But the Hoover Dam proposal would operate differently. The dam, with its towering 726-foot concrete wall and its 17 power generators that came online in 1936, would not be touched. Instead, engineers propose building a pump station about 20 miles downstream from the main reservoir, Lake Mead, the nation’s largest artificial lake. A pipeline would run partly or fully underground, depending on the location ultimately approved.
“Hoover Dam is ideal for this,” said Kelly Sanders, an assistant professor of civil and environmental engineering at the University of Southern California. “It’s a gigantic plant. We don’t have anything on the horizon as far as batteries of that magnitude.”
The Los Angeles Department of Water and Power, the nation’s largest municipal utility, says its proposal would increase the productivity of the dam, which operates at just 20 percent of its potential, to avoid releasing too much water at once and flooding towns downstream.
Engineers have conducted initial feasibility studies, including a review of locations for the pump station that would have as little adverse impact as possible on the environment and nearby communities.
But because Hoover Dam sits on federal land and operates under the Bureau of Reclamation, part of the Interior Department, the bureau must back the project before it can proceed.
“We’re aware of the concept, but at this point our regional management has not seen the concept in enough detail to know where we would stand on the overall project,” said Doug Hendrix, a bureau spokesman.
If the bureau agrees to consider the project, the National Park Service will review the environmental, scientific and aesthetic impact on the downstream recreation area. If the Los Angeles utility receives approval, Park Service officials have told it, the agency wants the pumping operation largely invisible to the public, which could require another engineering feat.
Among the considerations is the effect on bighorn sheep that roam Black Canyon, just below the dam, and on drinking water for places like Bullhead City. Some environmentalists worry that adding a pump facility would impair water flow farther downstream, in particular at the Colorado River Delta, a mostly dry riverbed in Mexico that no longer connects to the sea.
Even if no water is lost because of the pumping project, the thought of any additional stress on the system worries Toby Cotter, city manager of Bullhead City.
The town thrives on the summer tourism that draws some 2 million visitors to the area for recreation on the greenish-blue waters, Cotter said. “That lake is the lifeblood of this community,” he said. “It’s not uncommon to see 100 boats on that lake.”
Ivan Penn is a New York Times writer.