Despite the Hype, Batteries Aren’t the Cheapest Way to Store Energy on the Grid
http://www.theenergycollective.com/energy-post/2396202/despite-the-hype-batteries-arent-the-cheapest-way-to-store-energy-on-the-gridjanuary 12, 2017
...To be a sensible economic investment, the benefits have to outweigh the costs. In other words, the savings on your energy bill have to be greater than the capital costs plus the running costs.
There are many different kinds of storage technologies, each with different characteristics. Lithium ion batteries are attractive as they operate effectively at small scales, are lightweight and have good round-trip efficiency. But they are currently expensive per unit of storage capacity.
Pumped hydro at the other end of the scale operates at very large scales, has good round-trip efficiency and is very cheap per unit.
Flywheels (or rotors) have low round-trip efficiency and don’t store a lot of power, but are able to dispatch lots of power in a short time and can also contribute to frequency stability.
Other storage technologies include compressed air, cryogenic (liquid air) energy storage, flow batteries and hydrogen. Each has its respective pluses and minuses....
...Lithium ion batteries are coming down in cost at a significant rate. Bloomberg has plotted the costs of lithium ion alongside solar PV. This shows the two technologies share a similar cost curve gradient, with lithium ion reducing from US$1,200 per kilowatt hour to US$600 per kWh in five years (not including installation costs)....
...Pumped hydro, on the other hand, is a relatively inexpensive storage technology (already at around A$100 per kWh) as it can store large amounts of energy using a very inexpensive material.
All you need is some water and the means to pump it uphill. So while it can’t be used everywhere...
