A Florida utility announced recently that it plans to replace two natural gas plants with what it hopes will be "the world's largest solar-powered battery." Florida Power & Light's goal for its Manatee County facility sounds wonky, but it has huge implications for the future of renewable energy in the U.S.
Scientists have urged the world's governments to transition to renewable energy as much and as fast as possible to stave off the worst damage to the Earth's climate.U.S. and Puerto Rico have already set goals of using 100 percent carbon-free electricity in the next few decades, and a similar legislation.
But renewable energy, although it's cheap to produce and benign for the planet, isn't ideally suited for the U.S. electrical grid. Changes in the weather make wind and solar power variable, meaning the amount of power generated changes with the intensity of the sun or wind. By contrast, a fossil-fuel plant or a hydroelectric plant produces power at a constant rate that can be ramped up or down.
"If you've got 100 percent renewable energy, you have the problem of intermittency. There are times where the sun isn't shining and wind isn't blowing, so you have to back it up," said Geoffrey Heal, a professor of economics at Columbia Business School.
Storing renewable energy is key
Variability isn't a death knell for renewables, but it does call for more creative ways to approach power delivery than the U.S. has typically used. Chief among those is the need to store energy while it's being generated and then release it when needed.
Batteries are key to achieving this type of storage -- and companies have been competing with each other to create faster and cheaper versions. The world's biggest battery currently lives in the Australian state of, where it can store enough energy to shore up supply for the entire state. Six months after that Tesla-made battery went online in late 2017, it reportedly cut the grid's service costs by 90 percent.
The arms race to create bigger and bigger batteries has resulted in some significant cost reductions. The energy cost for battery storage has dropped 35 percent since last year, Bloomberg New Energy Finance reported last week. "Batteries co-located with solar or wind projects are starting to compete, in many markets and without subsidy, with coal- and gas-fired generation," the outlet wrote.
"100 million iPhone batteries"
FPL's battery promises to be four times as large as Tesla's -- or in the company's words, "the equivalent of approximately 100 million iPhone batteries" -- and store enough energy to power 32,000 homes for 24 hours. (That's about one-sixth of the housing units in Manatee County.) It will be charged by an existing solar power plant.
The utility also said it would upgrade existing solar power plants and install smaller batteries across the state to make up for the 1,600 MW of generating power that the gas-fired plants currently produce. According to FPL, the battery is scheduled to be operational in late 2021.
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