Most technologists have a general knowledge of widely used energy storage techniques such as Lithium-ion and lead-acid batteries, But what about more exotic stuff like flow batteries?
For those who want an overview of the current state of energy storage technologies having promise for smart grids, a recent DOE report might be useful. "Advanced Materials and Devices for Stationary Electrical Energy Storage Applications" was released late last month and report offers an initial assessment of materials science advances and breakthroughs that could improve performance and lower costs of the future electrical grid. It summarizes the results of a workshop held earlier last year in which experts representing academia, industry, and government convened in Albuquerque, New Mexico.
A roadmapping process conducted at this Advanced Materials Workshop examined the following specific storage technologies:
- Flow batteries
- Na-batteries, including both solid and liquid electrolyte batteries
- Li-ion batteries, emphasizing differences in requirement matrices between transportation and stationary applications
- Lead-carbon and other traditional batteries, with an assessment of their suitability for stationary applications
- Technologies for power applications, supercapacitors, and flywheels
- Emerging technologies and new concepts.
Flow batteries, by the way, store electricity in liquid electrolytes. During operation, the electrolytes flow through electrodes or cells to complete redox reactions and energy conversion. The electrolytes on the cathode side (catholyte) and the anode side (anolyte) are separated by a membrane or separator that allows for ion transport, completing the electrical circuit.
Researchers have identified a number of potential redox flow battery chemistries, including iron-chromium, all vanadium, and zinc-bromide in varied supporting electrolytes, such as sulfuric acid or hydrochloric acid. The capability of flow batteries to store large amounts of energy or power, combined with their potential long cycle life and high efficiency, is what makes them promising energy storage devices for grid energy applications and reasonable options for power applications.
The report goes into the challenges to overcome to meet market requirements for flow batteries, as well as for other technologies under consideration. The most notable challenge for most of the technologies is getting the cost reductions necessary to gain market acceptance for grid-scale applications. The full report and related information can be accessed from this page: