Solar-plus-storage projects spread as battery prices plunge

Source: David Ferris, E&E News reporter • Posted: Monday, April 8, 2019

The kickoff of a big solar-plus-storage plant in Florida — following one in Arizona and another in Arkansas — means that a new power duo is climbing the charts among electric utilities.

Last week, Florida Power & Light Co. announced the largest project ever to put solar panels and batteries in tandem. The 409-megawatt installation is an order of magnitude bigger than any such plant ever built in Florida, a state that’s been mostly indifferent to solar power despite its abundant sunshine (Energywire, March 29).

“The FPL one was, I don’t want to say shocking, but surprising for them to do something that big,” said Alex Eller, an energy storage analyst for research firm Navigant. “It’s an indication of how affordable this is going to get so quickly.”

For years, solar and storage experts have imagined a perfect marriage. Solar power has become cheap but is intermittent and available only in daytime; batteries can store that energy and shift it to when it is needed in the evening. But until now, the partnership has been rare outside states like California and Hawaii that support it with policy.

The new driver is the plummeting price of lithium-ion batteries. According to Bloomberg New Energy Finance, the per-kilowatt-hour price of these batteries has dropped from over $1,000 in 2010 to less than $200 in 2018.

Despite its new popularity, solar-plus-storage is not yet an answer to the Trump administration’s concerns about renewables not providing the reliability that traditional forms of grid fuel provide, such as coal and nuclear. The battery plants on the drawing board will delay the delivery of electricity for just a few hours, and won’t fill up on a cloudy day.

In February, Arizona Public Service Co., the largest utility in Arizona, said it would add an astonishing 850 MW of energy storage to its grid. This includes 200 MW of storage to sync with existing solar power plants and 150 MW of batteries to pair with energy storage installations yet to be built.

Then, last month, Arkansas learned it will be home to a new 100-MW solar plant to be paired with a 30-MW cluster of batteries. The project is the largest to be undertaken so far by Entergy Corp., the largest electricity provider in Arkansas, Louisiana and Mississippi.

More such projects are probably on the way, Eller said.

Solar and storage companies can make a stronger business case to utilities as the economics have improved. One leader is NextEra Energy Resources, which is building out the Arkansas project and is a sister company to FPL.

Another reason is the federal solar investment tax credit, which is winding down but still offers utilities a sweet deal on solar-plus-storage plants until 2021.