To the uninitiated, it may seem that grid energy storage is a non-sequitur, since supply often barely meets demand. However, peak period shortfalls are precisely the reason grid power storage is so critical to a consistent power supply. Grid storage systems would preserve those kilowatts that would otherwise go to waste during low demand periods. This ability is key to conserving energy and keeping the cost of electricity at an affordable level. However, to date, no single grid energy storage alternative has earned widespread approval as both cost-effective and efficient on a large scale, although grid storage battery development is rapidly escalating, with vanadium redox flow battery technology outpacing the others.
Source: http://www.americanvanadium.com/vanadium-flow-batteries.php
