An oft-repeated refrain—the sun doesn't always shine, and the wind doesn't always blow—is sometimes seen as an impediment to renewable energy. But it's also an impetus toward discovering the best ways to store that energy until it's needed.
Declining costs in available technologies have propelled interest in energy storage forward like never before. The price of lithium-ion batteries has fallen by about 80% over the past five years, enabling the integration of storage into solar power systems. Today, nearly 18% of all electricity produced in the United States comes from renewable energy sources, such as hydropower and wind—a figure that is forecast to climb. And as communities and entire states push toward higher percentages of power from renewables, there's no doubt storage will play an important role.
Compared with the same period a year earlier, the United States saw a 93% increase in the amount of storage deployed in the third quarter of 2019. By 2024, that number is expected to top 5.4 gigawatts, according to a forecast by market research firm Wood Mackenzie Power & Renewables. The market value is forecast to increase from $720 million today to $5.1 billion in 2024. Driving such growth is an increased focus on adding renewable energy sources to the nation's grid.
Only in the past decade has the widespread adoption of renewable energy sources become an economic possibility, said Paul Denholm, a principal energy analyst at the National Renewable Energy Laboratory (NREL). He joined NREL 15 years ago and, at the time, he and other analysts were busy plotting a path to 20% of the nation's energy supply coming from renewable sources. Now, they're aiming much higher.
"The declining cost of wind and solar and now batteries makes it conceivable to consider 100% renewables," he said.
NREL's Renewable Electricity Futures Study estimated that 120 gigawatts of storage would be needed across the continental United States by 2050, when the scenario imagined a future where 80% of electricity will come from renewable resources. The country currently has 22 gigawatts of storage from pumped hydropower, and another gigawatt in batteries.
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