Energize Weekly, February 28, 2018
Florida Power & Light Company (FPL) said it is adding “cutting-edge” storage technology to a utility-scale solar facility that will boost output by half-a-million kilowatt-hours a year.
FPL, the nation’s third-largest electric utility with five million customers, said that the integration of the DC-coupled battery array is believed to be the first large-scale application of the technology in the country.
The 4,000-kilowatt system, with 16,000 kilowatt-hours of storage, is being added to FPL’s 74.5-megawatt Citrus Solar Energy Center, in DeSoto County. The solar facility went online in 2016. The company did not release the cost of the project.
“With advances in battery storage technologies, we are looking at the next level,” Eric Silagy, FPL CEO, told DeSoto County environmental and community leaders earlier this month.
“By harnessing more solar energy from the same power plant, this has the potential to further reduce our fossil fuel consumption and save our customers even more money on their electric bills,” Silagy said.
Batteries can be added on either side of the inverter, which transforms the direct current (DC) from solar panels to the alternating current (AC) used on the grid. While DC batteries have had a higher efficiency rate than AC at scale, they have been more expensive and complicated to add.
The DC-coupled batteries store energy directly from the solar panels and have the advantage of being able to harness extra energy that a solar plant generates when the sun’s rays are the strongest. It also can avoid some energy losses associated with the inverters during these high-generation periods.
“During these optimal operating periods, a solar plant may generate more power than its inverters can process, resulting in some energy inevitably being lost—or ‘clipped’ by the inverter,” FPL said in a statement. “Unlike other batteries, a DC-coupled system can capture this extra clipped energy, thereby increasing the amount of energy the plant delivers to the grid.”
The DC-coupled system like other battery systems can store and dispatch electricity to the grid over time.
The installation at the Citrus Solar Center came after FPL commissioned several battery storage pilots in 2016. FPL is the largest generator of solar energy in Florida with 10 major solar power plants and solar installations having 635 megawatts of capacity.
The company said it is undertaking “one of the largest solar expansions ever in the eastern U.S.” It has added more than 520 megawatts of photovoltaic solar in the last two years and has nearly 300 megawatts more scheduled to enter service by March 1.
FPL is a subsidiary of NextEra Energy whose companies operate about 130 megawatts of batteries with 100 megawatt-hours of storage.
