Solar panels and windmills are great. But what happens when the sun goes down or the wind stops blowing? Do we content ourselves returning to the pre-industrial world for the night?
Burning natural gas when renewable energy sources aren't available is one solution often discussed in the scientific community. At least we can cut fossil fuel use for two-thirds of the day.
Another solution is storing excess power from solar panels and/or wind turbines and releasing it when energy can no longer be generated from the environment. The National Renewable Energy Lab claims that storing energy in batteries allows for flexibility in energy use. It creates a backup supply of renewable energy that can be used when energy demand is higher than expected.
Windpower Engineering, an online windpower news aggregator, explains that the most common type of battery used for renewable energy storage is a lithium-ion battery, which works like a standard rechargeable battery — but on a much larger scale. These batteries charge and discharge by transferring positively (or negatively) charged lithium atoms between electrodes, which subsequently causes electrons to flow in or out of a device. They have a large energy density (amount of energy per volume) but may not work well for long-term storage. Lithium-ion batteries are well-studied, and researchers are optimistic their cost-effectiveness and storage capacity will continue to improve.
Another form of large-scale energy storage is the redox flow battery. This kind of battery uses liquid solutions instead of solid electrodes. Researchers at Windpower Engineering state that there is “no inherent degradation” of the solutions when this battery charges and discharges, which allows for incredibly long usage. While redox flow batteries have lower energy density and take up more physical space, they can be stacked to reduce horizontal sprawl. This stacking also makes it easy to configure how much energy can be stored at a given location based on how large each battery is and how many are stacked.
Sources
Bowen, Thomas, Ilya Chernyakhovskiy, and Paul Denholm. “Grid-Scale Battery Storage: Frequently Asked Questions”, National Renewable Energy Lab, Sept. 2019. https://web.archive.org/web/20220127051533/https://www.nrel.gov/docs/fy19osti/74426.pdf. Accessed and archived 26 Jan. 2022.
McKay, Chris. “How three battery types work in grid-scale energy storage systems”, Windpower Engineering, 18 Mar. 2019. https://web.archive.org/web/20220127051216/https://www.windpowerengineering.com/how-three-battery-types-work-in-grid-scale-energy-storage-systems/. Accessed and archived 26 Jan. 2022.
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