Here are four innovative ways we can store renewable energy without batteries. Giant bricks are not what most people think of when they hear the words “energy storage”, but they are a key element of a gravity-based system that could help the world manage an increasing dependence on renewable electricity generation.
How do you store energy?
You can store electricity in electrical batteries, or convert it into heat and stored in a heat battery. You can also store heat in thermal storage, such as a hot water cylinder. Energy storage can be useful if you already generate your own renewable energy, as it lets you use more of your low carbon energy.
Energy storage can come from any number of sources—natural gas, wind, solar. But having the ability to store energy will allow utilities to put more intermittent renewable energy on the grid. This lithium-ion installation from AES Energy Storage is currently the largest in the world at 30 MW/120MWh.
Pumped-storage hydroelectric dams, rechargeable batteries, thermal storage, such as molten salts, which can store and release large amounts of heat energy efficiently, compressed air energy storage, flywheels, cryogenic systems, and superconducting magnetic coils are all examples of storage that produce electricity.
Which energy storage method is most commonly used?
Hydropower is the most frequently used mechanical energy storage method, having been in use for centuries. For almost a century, large hydroelectric dams have served as energy storage facilities. Concerns about air pollution, energy imports, and global warming have sparked an increase in renewable energy sources, including solar and wind power.
If you have a renewable electricity generator like solar panels or a wind turbine, installing energy storage will save you money on your electricity bills. You need to weigh the potential savings against the cost of installation and how long the battery will last.
How do utilities store energy?
However, utilities also need to store a lot of energy for indefinite amounts of time. This is a role for renewable fuels like hydrogen and ammonia. Utilities would store energy in these fuels by producing them with surplus power, when wind turbines and solar panels are generating more electricity than the utilities' customers need.