NextEra's (NYSE:NEE) Florida Power & Light (FPL) announced today the completion of its five-year, multibillion-dollar nuclear uprate project. NextEra previously estimated in December 2012 that the modernization work would add 400 MW of new capacity, but the final results clocked in 25% higher, at 500 MW.

With its two Florida nuclear plants modernized, nuclear energy now accounts for around 16% of NextEra's total 42,000 MW of generation capacity.

According to FPL President Eric Silagy in a statement today:

With consistently low fuel costs, zero emissions and the ability to operate around the clock, nuclear power is a critical component of our state's energy mix today and tomorrow. By increasing the amount of power that our nuclear plants can generate, this investment added the equivalent of a new, medium-sized power plant to Florida's generation fleet, without having to build one.

According to NextEra, this project is the largest U.S. nuclear project in recent history, and is expected to result in around $100 million of efficiency savings in the next year alone.