Surplus Power Lights Up MWD Desalination Plans

It is a dramatic example of how California’s electricity forecast has morphed from shortage to surplus: The giant Metropolitan Water District has restarted plans to strip salt from seawater as a new source for Southern California’s taps.

For decades, desalination has been talked of as a solution to the Southland’s water needs. And for decades, it has been dismissed as too energy-intensive to be affordable.

Now the idea is coming back, in part as a way to soak up surplus electrons.

For 17 million consumers of the MWD’s water--most of whom are also customers of Southern California Edison--the idea carries a painful irony: A portion of their big electricity bills will go to pay for expensive surplus power that, in turn, may be used to produce expensive water.

How expensive? At a small desalination plant near Monterey--one of the few in use in California--producing enough tap water to serve one family for a year costs more than $1,000. Even with the newest technology, a plant under construction in Florida promises to produce that amount of fresh water for about $400--still almost twice the MWD’s current average cost of water.

Much of the cost comes from the electricity used to force seawater through layers of salt-catching membranes in what is called reverse osmosis. At a Santa Barbara plant that ran briefly a few years ago, engineers found that producing enough water to last an average family a month consumed enough electricity to supply the same family for two weeks.

Power Surplus Offers a New Opportunity

In a state that as recently as four months ago experienced a rolling blackout and electricity price spikes big enough to bankrupt its largest utility, such a power-guzzling technology might seem the last idea anyone ought to embrace.

But the electricity crisis triggered a rush to build new power plants and produced a series of contracts that commit the state government to buy power in large amounts for years to come. Gov. Gray Davis says the state needs to have a 15% power surplus to guarantee that Californians will never again be at the mercy of power generators when demand soars.

Maintaining such a big surplus, however, inevitably raises the question of what to do with all the excess power when demand is normal--or lower. Much of this summer, the state has been selling the surplus electricity for pennies on the dollar, and state forecasters expect the surpluses to grow through 2004 as 11 large power plants now under construction begin operation.

That’s where MWD leaders see an opportunity.

“With all the activity, people making investments, you may find there are people who are overextended on building these [power] plants,” said Ronald R. Gastelum, general manager of the MWD, which supplies water to 26 water agencies and cities from Ventura to San Diego.

The owners of those power plants might be eager to find a home for their electrons in a desalination facility, Gastelum believes.

The idea is more than just speculation. The MWD board has voted to solicit proposals for desalination projects capable of supplying as many as 250,000 people. To encourage such ventures, they have also agreed to subsidize the price of the water.

Most of the power plants under construction or planned for the state are inland, while seawater desalination plants must be near the coast. But California’s transmission grid serves as an equalizer, said Gastelum. Electricity pumped onto the grid near Bakersfield, for example, could offset the power a water plant in Long Beach would consume.

“You could conceivably marry that seawater desalination demand with your inland demand, and your net result is you’re fully subscribed and the average cost might work for you,” Gastelum said.

Southern California water leaders also say they want to make sure that as the big, aging power plants on California’s coast get overhauled or expanded, the option of someday attaching desalination plants to them is not foreclosed.

“It’s a lot easier to acquire the land and protect it now than it is to try to dislocate somebody that’s built up a business or family or community,” said Stan Sprague, general manager of the Municipal Water District of Orange County.

The production of electricity and the conversion of ocean water to drinking water can work well together because the two types of plants can share the pipes that take water from the ocean and back. Seawater used to cool power plants, once warmed, is more easily stripped of its salt.

The biggest desalination plant in the Western Hemisphere is under construction next to a power plant at Tampa Bay, Fla. The plant promises to produce cheaper water with more advanced filters and has helped renew interest in desalination across the nation.

In Southern California, it’s just another phase in a long flirtation.

Thirty-five years ago, the MWD set out to construct an island off Huntington Beach to house the world’s largest nuclear-powered seawater desalting plant. The complex would have generated water for nearly 700,000 people and power for 1.3 million.

After the estimated cost nearly doubled in 1968, the project was abandoned. Today there are just a handful of small plants in California treating pure ocean water. They include one in the basement of the Monterey Bay Aquarium, another at the visitors center of a state park at San Simeon and a backup plant on Catalina Island.

Plants that use the same technology to strip impurities from brackish ground water and sewage effluent are more common and cheaper to operate.

In the early 1990s, the MWD built and then dismantled a pilot desalination plant at Huntington Beach. The facility worked, but its purpose was strictly to test new materials. No company or agency has yet shown an interest in paying the MWD to use the particular technology tested at the plant.

Desalination is just too expensive compared to other sources of water, critics say.

‘The Question Is: Can We Afford It?’

“It’s hard not to look at that huge body of water and think, ‘If only I could get that salt out of there,’ ” said Peter Gleick, executive director of the nonprofit Pacific Institute for Studies in Development, Environment and Security in Oakland. “We can get the salt out of there. The question is: Can we afford it?”

“We’ve always had cheaper alternatives,” he said. “And we still have cheaper alternatives.”

Those alternatives, however, may not always be able to meet the needs of Southern California’s rising population.

Most of the MWD’s water arrives via canal from the Sacramento-San Joaquin delta, hundreds of miles to the north, and the Colorado River to the east. Neither source is as reliable as MWD officials would like.

Federal biologists regularly trigger the shutdown of delta water pumps to protect salmon and other endangered species. And after decades of using as much as 20% more water from the Colorado than its allotted share, California has been sternly warned by the federal government to wean itself off the extra amount.

The MWD has responded with an array of projects, including paying Imperial Valley farmers to use less Colorado River water and treating waste water so it can be used to irrigate landscaping.

The company building the Tampa Bay desalination plant helped persuade the MWD to investigate the technology as another way to expand water supplies.

Poseidon Resources, based in Connecticut, is studying the construction of desalination plants next to power plants in Huntington Beach, Long Beach, Carlsbad and the port of San Diego.

By asking Poseidon and other companies to submit proposals this fall, the MWD is giving private industry an opportunity to show whether technical improvements in reverse osmosis make desalination cheaper, Gastelum said.

Even if the MWD subsidizes water from a desalination plant at $250 an acre-foot, said Kevin Wattier, manager of the Long Beach water department, it would still cost hundreds of dollars more per acre-foot than water imported from other regions. An acre-foot--enough water to cover one acre to a depth of a foot--is about the amount that two typical families consume in a year.

Yet the appeal of the technology never completely vanishes and sharpens during drought or when political battles over Northern California water intensify. A desperate Santa Barbara, for example, built a $34-million desalination plant in 1991, the most critically dry year of a seven-year drought that left one of the city’s reservoirs all but empty.

The desalting plant ran for just three months. Santa Barbarans had voted overwhelmingly to construct the plant but also to tap into the State Water Project, which brings Northern California water south. Santa Barbara had to pay for the imported water regardless, so the city consumed it and mothballed the desalination plant, which produced water at a cost of about $1,100 an acre-foot. Key parts of the plant have since been sold to Saudi Arabia.

“Southern California has a hard time figuring out what to do about desalination,” said Wattier, “because we have a hard time figuring out what we can ever expect from the [San Francisco] Bay-delta system.”

Agency Willing to Subsidize Projects

MWD officials say they are willing to subsidize desalination projects, much as they subsidized water recycling projects, to sharpen the appetite for the water among the dozens of districts and cities that the district serves.

The subsidy is justified, they say, because any water produced through desalination is water that the MWD will not have to secure elsewhere, such as by paying San Joaquin Valley farmers to store flood flows in their ground water basins.

“The hope is that if Metropolitan puts up $250 an acre-foot, that will add enough incentive to local districts to go out and build a desalter or two,” said MWD board member Langdon Owen, an engineer who represents the Municipal Water District of Orange County.

The advantages are many, he said: The ocean is a water supply free of the vagaries of snowfall, unfettered by laws that protect salmon. Desalination does not deplete aquifers. And the process generates water so clean it can be recycled several times before being dumped back into the ocean.

But cost remains the big hurdle.

“The technology to do reverse osmosis--and particularly the development of the membranes--has been improving rapidly the last few years,” said Jeanine Jones, drought preparedness manager for the state Department of Water Resources.

“But it’s still a costly process,” she said. “We’re still not there yet.”

For now, that’s the reality. “Everybody agrees it’s going to happen sooner or later,” said Wattier. “The whole debate is about when.”