Storage Methods to Solve the Energy Grid Problems
- August 13, 2018
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New storage methods can solve the problems inherent with electricity delivery. With renewable energy sources, the generators only create electricity if conditions allow. For cloudy or still days, storage units deliver stored electricity to homes. Storage units also solve problems of power drops and surges. Energy companies are currently adopting these storage methods to even energy flow and delivery.
This method uses gravity and pumps to store and use electricity from water. This storage requires an elevated area for a reservoir and a much lower spot for a secondary reservoir and the power plant. Water in the upper reservoir drops down and turns the turbines with the flow of water. When energy use has been met, pumps reverse the flow of water to send water back from the lower reservoir to the upper one.
Though worldwide, 99 percent of energy storage uses pumped hydropower, it cannot be used everywhere. This form of storage requires elevated terrain to work. Not all areas have this feature. Locations in flatlands will need to use alternative energy storage methods.
Zinc-hybrid batteries are a newer, more expensive flow battery, though zinc itself is cheaper than many flow battery materials. These batteries operate by a chemical reaction that produces oxygen and electrons. These electrons flow to the cathode.
Zinc-hybrid batteries work best to provide four hours of energy, but the systems are built for 20 years. The efficiency can be to 70 percent. The best applications for zinc-hybrid batteries are for solar storage. These batteries are most efficient with a regular discharge-charge cycle.
Compressed air uses a reservoir to store energy. Instead of using an above grade reservoir, compressed air uses an underground chamber to store compressed air. When supplementary power is needed, the stored air becomes heated. This expands the air and causes it to rise to the surface to drive turbines.
Though this method is the second-most used form of energy storage, it has limitations. Like hydropower, it requires specific terrain. It also depends on using fossil fuels to heat the air for use. Finding local permission to construct a compressed air facility may be difficult as these take up a large space. But it's not impossible. One of these facilities is in development by the Pacific Northwest National Laboratory to supplement the power in Oregon and Washington.
Solid-state batteries don't rely on moving electrolytes. Most people know about these batteries as they’re the same type used in consumer electronics. The solid-state batteries used for the grid have similar problems as their smaller counterparts. With each charging cycle, the battery's life decreases slightly. This limits the battery's life, depending on how often it's used.
Tesla, known for its electric cars, also has created consumer-level and grid-level lithium-ion batteries. The Powerwall is designed for use with the grid. It's first use in Australia allowed for the storage of 129 MW of energy from a wind farm. This energy had the ability to supply electricity to 30,000 homes.
High-speed flywheels are being honed for improved use with the grid. This storage method has a few hurdles it needs to overcome before it can be integrated fully into the grid. First, these can be dangerous. With any flywheel application, there is a danger of the flywheel dislodging from its axis. To prevent the flywheel from harming those nearby, it must be built inside secure walls to hold the flywheel in place.
Secondly, flywheels are not designed for long-term storage. They work best to store and discharge electricity temporarily. When the flywheel spins, it houses energy. The faster it spins, the more energy it stores. This makes it suited for power applications, which requires it to discharge power in an hour or less. Because it's not a long-term energy storage source, it's not well-suited for most grid applications now.
Cleaner Energy Solutions
To use clean energy, the electricity generated must be stored. But the storage method should be as green as the means of energy creation. These storage solutions are currently helping countries all over the world embrace green energy, store it for later use and deliver it to other places. A greener tomorrow is starting today with better storage solutions for electricity.
Photo by American Public Power Association on Unsplash