Rising water temperatures and severe algae blooms in cooling canals have threatened to force the shutdown of two nuclear reactors at Florida Power & Light’s Turkey Point plant over the last few weeks.
The utility and federal regulators say there isn’t a public safety risk but the canal temperatures, climbing to 94 to 99 degrees, have come within one degree of a federal limit that would mandate an expensive shutdown at a time when power demands are soaring. The hot water has also stoked the spread of algae through the 168-mile long canal system, which has helped keep temperatures high and reignited concerns about the power plant’s impact on water quality in Biscayne Bay.
In a letter last month to state regulators, the company asked to control the algae with herbicides and to cool the canals with daily injections of millions of gallons from an underground reservoir that supplies Miami-Dade County’s drinking water — requests that drew questions from Biscayne National Park and environmentalists. FPL has also asked the Nuclear Regulatory Commission to raise the 100-degree operating limit to 104 degrees to keep the reactors on line.
“The urgency in all of it is that we’re in the summer. Demand on the grid is very high and we have to make sure we can service our customers,” said FPL spokeswoman Bianca Cruz.
In an effort to address concerns, FPL on Wednesday outlined its plans during a meeting of federal, state and local agencies overseeing restoration of Biscayne Bay.
Worries over damage to the bay, now protected in a national park, have dogged the plant since FPL dug the sprawling canal system in the 1970s after environmentalists sued to stop billions of gallons of hot water from being pumped into the bay. Environmentalists also worried that a recent $3 billion overhaul of the plant, which allows FPL to generate up to 15 percent more power, could worsen the inland creep of an underground plume of saltwater that threatens drinking water well fields in South Miami-Dade County.
But Matt Raffenberg, FPL’s environmental services director, said Wednesday that the overhaul, called an uprating, had not caused the jump in temperatures and was not harming the bay.
“There are things going on in the cooling canals we’re trying to manage,” Raffenberg said. “But in terms of impacts to Biscayne Bay, we don’t see data suggesting the cooling canals are affecting bay water.”
In a June 27 letter to the South Florida Water Management District, an FPL manager asked for emergency withdrawals of up to 30 million gallons a day of cooler water from a brackish section of the underground Biscayne Aquifer — source of most of Miami-Dade’s fresh water — to avoid shutting down its two reactors and a natural gas plant.
That same day, the Florida Department of Environmental Protection agreed to allow FPL to pump up to 14 million gallons a day but from a deeper source, the Floridan aquifer. DEP also approved the utility’s plan to dump herbicides, including copper sulfate and hydrogen peroxide, for up to 90 days to kill algae boosted by the warmer water.
The NRC, meanwhile, is still evaluating FPL’s request to increase the cooling canal temperature limits for operating the reactors.
“What they’ve run into more recently is (temperatures are) trending higher than historical averages,” said NRC spokesman Roger Hannah. “It is very warm because most plants in the country, and I don’t know specifically for all plants, but most plants would have temperatures much lower.”
High water temperatures, an algae bloom and a spreading underground saltwater plume may not appear related but they do highlight the complexity of operating a plant that depends on cool water in steamy South Florida.
“With a big industrial facility next to the park, you’ve got be concerned, said Biscayne National Park superintendent Brian Carlstrom. “I’d rather be on the side of erring with an abundance of caution than be on the response side of trying to mitigate an environmental catastrophe.”
Last month, George McHugh, the park’s chief of administration, wrote federal, state and local officials asking for an investigation into the “broad poor water quality trends, their source and potential solutions.”
Worsening salt water intrusion, which can alter native coastal habitat, is the biggest threat.
A U.S. Geological Survey mapping the leading edge of the plume earlier this year showed the biggest advance since 1995 in Florida City, just northwest of the sprawling grid of canals. In 2009 and again in 2011, water managers and environmentalists worried that tapping the aquifer to cool canals would worsen saltwater intrusion.
The chemical request also raises concerns, said Julie Dick, an attorney for the Everglades Law Center.
“When they’re doing things on an emergency basis, it makes it hard for all the responsible agencies to deal with all the issues. There should be more forward thinking,” she said. “These aren’t necessarily benign chemicals being applied and additional monitoring is needed.’’
Mining companies just west of Turkey Point have also argued that saltier water from the sprawling canal system, which is heavier than freshwater, has sunk deep within the aquifer and migrated west, threatening their business as well as drinking water wells.
“When they were originally conceived and designed in the late 60s and early 70s, they were supposed to theoretically operate in a way that the salinity in the canals was going to mimic what’s in the bay,” said Ed Swakon, president of EAS Engineering and a consultant for Atlantic Civil, which operates a large mine just west of the canals. But over the years, salt built up, he said, making the water heavier and forcing it deeper underground.
At some 70 feet below the surface, he said, “it begins to spread like an inverted mushroom.”
FPL maintains salt water intrusion issues have existed since the 1940s and its canals have not played a part in the spreading plume.
“The canals are definitely a closed system,’’ Cruz said. “They don’t touch any other source of water.”
But on Wednesday, Scott Burns, a chief environmental scientist with the water management district, said tests conducted in recent years indicate underground water is creeping west. And in a letter last month, Justin Green, chief of DEP’s office that permits power plants, said FPL has been “put on notice” about the creeping plume. DEP and the water management district, he said, are drafting an order to deal with it, which will include pumping water from the Floridan Aquifer, deep below the Biscayne.
“When we increase pumping, that will reduce salt seepage and stabilize the system,” Burns said.
But Phil Stoddard, mayor of South Miami and a longtime critic of Turkey Point’s nuclear operations, worries drawing more water from the lower aquifer will make things worse.
"All the crap we've thrown into the Floridan is going to end up in the Biscayne Aquifer heading toward the drinking water," he said. "The green slime is absorbing heat and heating up the water. The problem for FPL is hot water doesn’t do such a good job of cooling the pipes."