Scuba diver John Vincent sensed something was wrong when, fishing for lobster one night off Playa del Rey, he felt a strange current.
It grew stronger. Seconds later, Vincent, 49, was swept into the mouth of a huge intake pipe for the Los Angeles Department of Water and Power's Scattergood power plant.
He tried to kick against the flow, but it was no use: Down the pipe he went, clutching his flashlight and his limit of lobsters, a long, fast journey through the dark. "I was flipping out," he said. "My air supply was running out."
Vincent's misadventure was exceptional. Most of the organisms sucked into power plant intake pipes off the California coast are plankton and small fish.
But his story provides an unusual firsthand perspective on a process at the heart of a messy controversy coming to a head before the State Water Resources Control Board.
Every day, intake pipes such as the one that caught Vincent are permitted to suck in enough seawater to fill Lake Arrowhead, then spit it out again, a little warmer and a lot deader. The seawater is used for cooling mechanisms in power plants, and for decades, it has provided California's electricity generators with a cheap and convenient way to keep the lights on.
Now state water board regulators are mulling a plan to force the power companies to spend billions to stop vacuuming the ocean for water to cool their machinery. Mostly, the companies don't want to. That's the simplified version of what's becoming an epic tug-of-war between two reliable California obsessions, energy and coasts, each backed by its own scientific spin and political clout.
Environmentalists say the intake pipes destroy too much sea life; utility advocates say that the impact is minimal and that banning the practice would cost too much, jeopardize the reliability of the electricity grid and slow the state's transition to clean energy.
The issue mainly concerns small animals and microorganisms. Large members of the animal kingdom, Vincent included, are prevented from entering the plants by screens. He survived in a catch basin. But fish can die while trapped against these barriers. Anything smaller than the openings in the screens, including millions of tiny fish larvae, enters the power plants and dies.
Federal rules have banned new plants from drawing in seawater for so-called "once-through" cooling systems. Now the state water board wants to apply this rule to the 19 existing plants dotting the coast from Eureka to San Diego.
The board's proposal would allow owners up to a dozen years to comply and contains special provisions for nuclear-plant safety issues and changes that might put the state's power supply at risk. But in most cases, it would require plants to supplant seawater pipes with massive cooling towers that recycle water, or to use air-cooling platforms.
Environmental groups laud the proposal, which they say comes after decades of efforts to get resistant power plants to comply with the federal Clean Water Act.
Utilities say it would force expensive retrofits or shut down plants. The combined cost for the Los Angeles Department of Water and Power, PG&E and Southern California Edison would surpass $8.5 billion, they say.
Interim DWP Chief S. David Freeman said his utility's $1 billion tab to comply is about what DWP was going to spend on switching from coal to wind and solar sources.
The measure also could force the municipal utility to temporarily shut down its relatively clean-burning natural-gas plants and rely more on inland coal power stations, he added.
"I am working hard on issues that I think everyone would agree are far more important than some minor impact on the fisheries," Freeman said.
Environmentalists don't buy it. Power plants are responsible for "the unnecessary sterilization and death of coastal waters," said Tom Ford of the environmental group Santa Monica Baykeeper.
The extent of this damage is disputed. Coastal fish are slippery in every sense: hard to count, and hard to count on. Their reproduction varies from year to year, their populations rise and fall, and their path from egg to adulthood in some cases is mysterious. Some species are spiraling down from overfishing and habitat loss.
Scientists are reduced to making estimates of estimates, leaving room for opposing sides to make contrary arguments using the same studies.
Environmentalists emphasize the loss of millions, even billions, of fish larvae, eggs and other organisms from power plants. But fish employ a reproductive system a little like dandelions, scattering clouds of offspring, of which a tiny fraction will survive. So such figures are less eye-popping when compared with vaster numbers of larvae in the sea, most of which would die anyway.
Utility interests commonly express the loss as a proportion of fish populations depleted because of the lost larvae. By that yardstick, less than 1% of the populations of many species on the southern coast are affected.
To be sure, cooling systems at some plants have serious and measurable effects.
PG&E's Diablo Canyon nuclear power plant has warmed the waters around it so much that, ecologically, it now resembles "a Mexican sea," said Gregor Cailliet, an emeritus professor and fish expert at Moss Landing Marine Laboratories.
Southern California Edison carried out $400 million in mitigation at its San Onofre nuclear plant, including construction of an artificial reef and a marsh near Del Mar, after the plant damaged kelp fields.
The effects of other plants are not as great, and those on open water along sandy beaches are thought to do less damage.
Ford, of Baykeeper, said that in the face of unknowns, it's safe to assume that sterilizing massive quantities of ocean water does the coastal food chain no good. "Mother Nature does not produce largesse," he said.
But generators argue the huge costs should be weighed against what they call tiny benefits. "There's a difference between a cut finger and a bullet to the heart," said DWP's Freeman.
One way scientists have tried to clear a path through this maze is by calculating how many acres of wetlands would mitigate the loss of fish to cooling systems.
Those restorations can have a more positive effect on fisheries than shutting down the cooling apparatus, said Peter Raimondi, professor of marine ecology at UC Santa Cruz.
But environmentalists have successfully fought habitat restoration in lieu of retrofits.
As a result, the water board's proposal has a potential to become an all-or-nothing battle. Power companies dread a blanket policy that allows no room for lower-cost options. Environmentalists fear loopholes that might allow the power companies to do nothing.
Vincent, the scuba diver, remains agnostic. He was saved after he was able to climb to a ledge just above the water line in a catch basin at the end of the pipe.
He saw a grate 30 feet above him and banged his diving weights against the wall to signal a passerby. Pulled out by firefighters, he got a free tour of the plant.
The experience left him with a fear of narrow places under water, but no strong feelings on the proposed policy. "I enjoy my power," he said.