While heat is needed to create energy, in parts of the process heat also is the enemy, Smith said.

The steam needs to be cooled to convert back to water, so it can repeat the cycle through the closed system. Part of the project is making the cooling water lines more robust.

“If they can handle more flow, they can handle more steam,” Smith said. “If they can handle more steam, they can create more power.”

Heat also is damaging to transformers, which are cooled by about 19,000 gallons of mineral oil, which does not need to be replaced.

Designers of the new transformer took into account its long trek over land and water, said Wade Lauer, Siemen Energy’s vice president of transformers for the United States.

“The whole transformer works on clearances,” Lauer said. “There is a risk if it shakes.”

The transformer was put in the bottom of the hull of the Star Eagle cargo ship. On the 180- by 150-foot barge, it was held down with 25 half-inch chains. “It won’t move an inch,” Colomero said a few minutes after he ended the 966-mile journey from Mobile.

The barge contained only the transformer’s shell. Ten semi-tractor trailers are hauling all the accessories — coolers, radiators, pumps and other parts — from Mobile, where they also were on the Star Eagle. It will weigh 850,000 pounds when it’s all put together in about a month.

The transformer’s new home for now is on a foundation next to the two nuclear units. Its shelf life is expected at 30 to 40 years.

FPL is doing a similar overall upgrade at its other twin nuclear power station in St. Lucie County. Parent company NextEra Energy also owns nuclear power plants in New Hampshire, Iowa and Wisconsin, making it the third largest operator of commercial nuclear power plants in the United States. The emissions-free electricity powers more than 5 million households.

“It’s clean energy,” Smith said.

But more nuclear power plants are not built because of the fear factor for some, and because they are initially expensive to construct. They also require an extensive licensing process that takes 10 years or more.

“But once they are built, they are very efficient,” Smith said. “And, they last a long, long time.”