Energy storage has been a fundamental part of the power grid since it was invented. It allows us to keep our power on when demand is greater than supply, and helps to moderate issues like power surges and storms. It only makes sense that these storage systems would have to be part of our power grid as we make the slow but steady change toward renewable energy.
Some of these systems are either already a part of renewable energy, or they’re easy to switch over. Since so many options of renewable technologies have variable outputs, it’s important to incorporate an energy storage system.
Since energy storage has been a vital part of maintaining any kind of reliability with our power grid, it’s good to have a basic understanding of it. Hydroelectric dams are usually a good visual. The water that runs through the dam is the active power being used, while the water stored behind it is the battery pack. When energy demand is low, water is pumped up to the storage area. During peak times, it rushes down. Currently, about 96 percent of the stored energy in the U.S. comes from hydroelectric plants.
This is a simple, basic way to understand and visualize how this energy works. However, there are limits to how much we can store with hydroelectric alone. With new technologies emerging, so are new forms of energy storage.
Flywheels are a lesser known form of energy storage. It stores energy in the form of a spinning mass. When there is excess energy from the grid, it accelerates to extremely high speeds. When the power grid needs energy, it slows down and runs on inertia, giving energy back to the grid for use.
The ease of transmission and distribution makes this a very effective storage method. One on its own can’t store much energy, but they can be linked together to create flywheel farms. This way, they can store a significant amount.
Compressed air is used in more ways than most people realize. It’s actually a very popular option for space travel, because there’s no heat and reduces the risk of fires. It’s also a popular option for communities that avoid other kinds of electricity, such as the Amish. Compressed air storage is also an excellent way to store wind energy.
A great deal of wind energy is produced at night, when energy consumption is low. It can also switch from energy storage to generation in very little time, which can help regulate fluctuations in the power grid. Typically, 75 percent running loaded and 25 percent off is the average for companies running air compressors. Since every storage facility needs to use some energy to run, this is a great return.
Everyone knows what batteries are. They come in all shapes and sizes, from little AAAs to car batteries that power your vehicle. There are batteries that are even larger than those, but either way, they are an important part of the energy grid. They’re often used in places like wind farms to help provide stability to the grid.
In the future, we can only expect battery costs to decrease. This is largely due to the automotive industry. As electric cars continue to become more popular, large battery production will continue to get cheaper.
Cryogenic Energy Storage
Cryogenic energy, or liquid air energy storage, is one of the newest forms. It’s the use of very low-temperature gases, such as air and hydrogen that are cooled to liquid form and used to store energy. Basically the gas is cooled to a liquid state, then allowed to come back to room temperature and become gaseous. As the gas expands, it turns a turbine that generates power.
Like flywheels, it has a low risk of malfunction and need for repair. It could eventually become a common way to generate and store power, especially as more green technology takes over.
No matter what you’re views are politically, there is no real reason to combat green energy. The worst case is that energy becomes cheaper for everyone, which is good news for our bank accounts and the planet.
Megan Nichols enjoys discussing environmental issues and other scientific discoveries on her blog, Schooled by Science.