April 19 (Reuters) - Florida Power and Light (FPL), a unit of NextEra Energy Inc, completed the upgrade of the 693-megawatt (MW) Turkey Point 4 reactor in Florida when the unit returned to service on Thursday.
FPL said the return of the unit marked the end of a five-year, multibillion dollar upgrade of the Turkey Point and St Lucie nuclear plants in Florida.
The company has said it expected to spend between $2.95 billion and $3.15 billion on the nuclear upgrade project.
FPL said the upgrades added more than 500 MW of new capacity to the plants, which is enough to power more than 300,000 Florida homes.
The upgrades of Turkey Point 3 and St Lucie 1 and 2 were completed in 2012.
FPL said the upgrades, known as "extended power uprates," surpassed the company's initial projection of 399 MW.
The company said an average of about 3,500 people worked on the project every day during 2012 alone.
The company also said the upgrades were expected to reduce emissions and save customers billions on fossil fuel costs, with more than $100 million in savings in the first year of operation alone.
Florida regulators approved of FPL's plan to upgrade the units in 2007.
Florida, like some other states in the U.S. Southeast, allows power companies to recover costs from nuclear upgrades during construction, which prevents certain development, construction and interest costs from compounding, FPL said.
FPL said this so-called "construction work in progress" cost produces hundreds of millions of dollars in savings for its 4.6 million Florida customers over time.
In 2013, FPL said its typical 1,000-kilowatt-hour residential monthly bill is about $95, of which the nuclear cost recovery clause represents $1.65 - about 5 cents a day.
FPL said nearly 90 percent of 2013 nuclear funding is related to the completion of the upgrades, with the remainder paying for continued development and licensing of two new reactors that could be built at Turkey Point.
In 2014, FPL said it plans to reduce its nuclear cost recovery to less than 50 cents on a typical customer's monthly bill, or less than 2 cents a day.
The company said it will file its official 2014 projections with Florida regulators in May.