Energy storage is a tool that can be used by grid operators to help regulate the electrical grid and help meet demand. In its most basic form, energy storage "stores" excess energy that would otherwise be wasted so that it can be used later when demand is higher. Energy Storage can be used to balance microgrids, perform frequency regulation, and provide more reliable power for high tech industrial facilities. Energy storage will also allow for the expansion of intermittent renewable energy, like wind and solar, to provide electricity around the clock. Some of the major issues concerning energy storage include cost, efficiency, and size.
- Make Renewable Energy Viable
- Allow for intermittent energy sources to provide continuous power
- Allow for deep renewable energy market penetration
- Serve as an "electricity Reserve"
- Act as a safety net for future emergencies
- Stabilize Electricity Markets
- Minimize disruption of major pricing moves due to weather, and natural disasters
- Reduce large swings between on-peak and off-peak electricity prices
- New Energy Market
- Create new market opportunities
- Allow for More Efficient Use of Existing Power Plants
- Reduces required peaking plant assets to meet peak demand
There are various forms of energy storage that are either currently being used or in the developing process. Each technology has its own advantages and disadvantages.
- Pumped Hydro
- Pumped hydro is currently the most widely used energy storage technology for large scale grid energy storage. It consists of pumping water to an elevated reservoir when excess energy exists on the grid, and when energy is needed, the water is allowed to flow back down through a turbine. This technology is very similar to hydro power.
- Compressed Air Energy Storage (CAES)
- Compressed air energy storage is a technology that compresses air when excess electricity is available and stores it in a pressure vessel. When demand increases, this air is expanded through a turbine in order to create electricity.
- Flywheel Energy Storage
- A flywheel is a large rotating mass that allows for kinetic storage of electricity. When excess electricity is available, it is used to power an electric motor which then spins a mass. When electricity is needed, the motor works in reverse transforming the kinetic energy back into electrical energy, slowing down the spinning mass.
- Batteries store electricity via chemical reactions.
- Plug-in Electric Vehicles (PEV)
- Plug-in electric vehicles are essentially batteries. The idea is that the vehicles can charge at night, when electric prices are low, and during peak hours, potential at places of work, sell energy back to the grid.
- Fuel Cell Energy Storage
- Fuel cell storage systems create hydrogen with available excess energy, such as electrolysis, and store it. When electricity is needed, the hydrogen is used to create electricity with the use of a hydrogen fuel cell.
- Capacitors store energy in a electric field between two plates. Energy can be rapidly stored and released to meet grid demands.
- Thermal Energy Storage
- Thermal energy storage is a method applied by some Solar Thermal Electric plants in order to generate electricity at night after the sun goes down.
- Superconducting Magnetic Energy Storage (SMES)
- Superconducting magnetic energy storage stores energy in a magnetic field created by a superconducting coil.
On Enipedia, an open-source experiment on bringing together energy information, a technology database has been created on Energy Storage: . Data from IEA, NREL, DNV KEMA and other institutions is included. This database provides energy storage technologies, products, demonstration projects and analysis. Also, an Energy Map is created listing other sources of data, and an overview of the future potential estimations is provided. The data is machine-readable (SparQL/RDF Linked Data) and open-source, working from Enipedia.