Thirsty cities look to sea for drinking water
By Stuart Leavenworth
-- Bee Staff Writer
SAN DIEGO -- Jittery about droughts and desperate fora secure water supply, this seaside city is making plans to tap California's largest untapped reservoir: the Pacific Ocean.
Courted by companies that promise cheaper ways to make drinking water from the ocean, the San Diego region is studying two sites for desalination plants. By 2006, the region hopes to receive 20 percent of its water from the ocean, and four other Southern California communities also are studying desalination.
A decade ago, desalting seawater was mocked as a money-wasting boondoggle that made sense only in the oil fiefdoms of the Middle East. But in recent years, the cost of desalination has dropped nearly in half, making it attractive to parts of California that no longer can count on a steady supply of water from the Sacramento-San Joaquin Delta or the Colorado River.
"We are not hydrologically blessed," said Dennis Cushman, a vice president with the San Diego Water Authority. "So we are looking for supplies that are drought-proof. Desalination is one of those supplies."
No longer a pipe dream, desalination offers some tantalizing prospects for a state weary of water warring. For decades, water has been a finite resource in California, meaning that to gain new water, regions had to take it -- or buy it -- from another part of the state.
San Diego, for instance, is trying now to buy water from the Imperial Valley. Companies also have approached the city with offers of water hauled down from Northern California in giant, plastic-lined bags.
By tapping the ocean, California finally could produce some new water, ease off the Delta and avoid the kind of haggling that comes from trying to transfer water from one part of the state to another.
"Desalination is the wave of the future," said Rich Golb, a water consultant who previously headed the Northern California Water Association.
Golb notes that desalination still poses challenges, such as how to dispose of the tons of salt that are left over from desalinating ocean water. Desalination plants also are vulnerable to rising electricity prices, such as the gyrations of last year's energy crisis.
Advocates, however, say those concerns can be addressed and should be balanced against the benefits of an evolving technology.
"There is no new imported water coming into California," said Paul Shoenberger of the West Basin Municipal Water District, an El Segundo-based water agency that is studying the option. "With the growth we are seeing, our only options are conservation, recycling of used water and desalination."
Along with many other water agencies in the state, the West Basin district for years has used desalination to treat groundwater drawn from salty coastal aquifers. Coastal power plants and other industries also employ the process, but until recently, the technology was frowned on by most urban areas, partly because of Santa Barbara's experience during the last drought.
In 1991, Santa Barbara built a $34 million desalination plant that closed three months after it opened because treatment costs were so high. In 1995, Morro Bay also mothballed a plant because of unexpectedly high costs.
In recent years, however, engineers have fine-tuned the manufacture of membrane filters, a key component of "reverse osmosis" desalination.
Made up of tightly rolled, polymer fabric, these filters once cost $1,250 each, treated 3,000 gallons of water a day, and lasted three years, according to Randy Truby, a vice president for Hydranautics, an Oceanside company that makes membrane filters.
Now, says Truby, the filters treat twice as much water, last twice as long and cost half as much. That's important, he notes, since a typical desalination plant uses 19,000 of the membranes at a time.
"There's been a quantum leap," said Truby. "People who say desalination is too expensive are quoting numbers that are 10 years old."
Desalination companies have learned they also can cut costs by engaging in joint ventures with existing coastal power plants. Under such arrangements, power companies get a cut of the water profits, while the desalination company gets to use the water a power plant already takes in for its cooling system. The desalination company thus doesn't have to build a new water intake pipe into the ocean, which usually involves a costly environmental permitting process.
"That's a big advantage," said Peter MacLeggan, a vice president with Poseidon Resources, a company that develops and operates desalination plants. "By using the cooling water of an existing plant, we are not taking any additional water from the ocean."
Based in Connecticut, Poseidon is among the more ambitious and fast-moving players in the field. The company, whose executive team includes a number of former General Electric employees, is developing a desalination plant in Tampa Bay, Fla., which will produce 25 million gallons of water a day.
When it opens early next year, the Tampa plant will be the first large desalination plant built for a U.S. city.
"Tampa is huge," said Patricia Burke, director of the International Desalination Association. "Everyone is watching it."
Here in California, Poseidon has courted Long Beach, Huntington Beach, San Diego and other communities, forcing competing companies to scramble in their tracks.
Two months ago, state health regulators issued a key drinking water permit for Poseidon's proposed plant in Huntington Beach, which will be coupled with an existing generating station owned by AES Corp.
North of San Diego, Poseidon has another strong prospect in the beach town of Carlsbad, home to the Encina Power Plant, owned by Dynegy/NRG.
Two weeks ago, MacLeggan wheeled his car through the gates of the Encina plant and parked near an ocean-fed lagoon, from which the power plant draws its cooling water. Every day, about 600 million gallons of water are drawn from this lagoon -- enough to fill 600 Olympic-size swimming pools.
Under the company's proposal, Poseidon would build a $250 million desalination facility at Encina, and use about 100 million gallons of cooling water from the power plant daily. One gallon of drinking water would be produced from every two gallons of ocean water. About 50 million gallons of leftover brine -- twice as salty as seawater -- would be diluted and returned to the ocean through the plant's existing outfall pipe.
Not every power plant is so suited for desalination, said Bob Yamada, a senior engineer for the San Diego Water Authority. Some are too far from a city's existing water pipelines. Others, such as a proposed plant in Chula Vista, are located on sluggish bays that can't handle additional salinity.
The Carlsbad plant, he said, is close to San Diego's water distribution system and has an outfall pipe that empties right into the crashing surf of Carlsbad beach.
"There's a lot of mixing out there," said Yamada. "That's what you need for a desalination plant."
So far, the proposed Carlsbad plant and others have generated little controversy, despite the close watch that Californians keep on their coasts.
Peter Gleick, an environmental researcher based in Oakland, says the ocean easily can absorb diluted discharges from desalination plants.
Gleick also dismisses arguments that the prospect of tapping the ocean will encourage coastal communities to go on a building binge. After all, he notes, the dearth of rainfall, rivers and lakes throughout much of California hasn't exactly stymied development: Traditionally, what water districts can't get from their own region, they've pumped in from another part of the state.
"Availability of water has never really constricted growth in this state," said Gleick, who heads the Pacific Institute for Studies in Development, Environment and Security. "That's a big myth."
Gleick, however, questions whether desalination is as cheap as some contend, or cheaper than alternatives, such as investing in water conservation.
"Desalination has a place in our future, but I'm not sure it's in the near future," said Gleick. "I fear we are missing a step by not exploring all the efficiency improvements that are still out there."
In the San Diego area, Poseidon is offering to provide 56,000 acre-feet of water yearly -- enough for 112,000 households -- and possibly double that amount.
The price would be $794 an acre-foot -- more expensive than Colorado River water, said Mac-Leggan, but cleaner and more reliable than the river water.
Over the last year, San Diego officials have been studying that $794 price, which is based on Poseidon running its plant on electricity costs of 6 cents a kilowatt-hour. Yamada, the senior engineer for the water authority, said he thinks the electricity price could be lower.
"We identified some areas where the cost could be brought down," said Yamada. But overall, he said, the company's water price "is in the ballpark."
One enticement for San Diego -- and Poseidon -- is a subsidy offered by the Metropolitan Water District of Southern California.
To spur innovation, Metropolitan last August offered to pay $250 an acre-foot to any of its agencies that submitted a winning proposal for desalination.
Last month, Metropolitan's staff recommended San Diego's Carlsbad project for the subsidy, saying it had made "significant progress" on environmental documentation. Should San Diego win the competition, its costs for purchasing water from Poseidon would drop to $544 per acre-foot.
The project still must receive a number of state and local permits, and Poseidon and the water authority still need a final contract. But Truby, the Hydranautics executive, says it is only a matter of time before the ocean starts delivering on its promise.
"Our population is growing. All the
easy water has been tapped," said Truby. "You can't keep building
canals and aqueducts to move water around."