By Randy Perretta

Storage. There’s a lot of talk going around these days regarding storage. But just what is it that’s getting all the attention? How does it work? Where does it work? How can it help me? Or is it just another abstract concept that’s found favor with futurists?

Let’s see if we can’t provide some answers to these questions and show what the benefits of storage are at the local and grid level.

Electricity as we know it on the grid can’t easily be stored. You have to match generation with demand, no more, no less. Storage provides a way out of that conundrum. The most well-known storage medium to date has been water. You use excess electricity at night to pump water uphill and then let it run downhill to power generators during the day when demand is high. Such facilities exist at Niagara Falls in NY and The San Luis Reservoir in California. The basic idea here and in other storage technologies is to transfer excess energy off of the grid to a medium where it can be stored so that you can transfer it back when needed.

A number of technologies are now being applied at the grid and local level to do just that. Spinning flywheels, compressed air, and most commonly, batteries are used to save energy when it is least needed and return it when it is most needed.

There are many applications for this. At the grid level, utilities can use stored energy to match demand and therefore avoid firing up gas-fired peaker plants which add to pollution and consumer expense. Solar installations, on the grid or in your home can use stored energy to replace lost output when the sun goes behind a cloud and, of course, wind systems can do the same when the wind dies down. Thus a level supply of renewable energy is assured which benefits businesses, consumers and utilities alike.

A very real application for homes and business is peak demand reduction. Utility tariffs are written to allow for surcharges during peak demand periods. Your electricity provider can charge you for additional use just when you need it the most — a hot afternoon when a hotel is experiencing a high air conditioning load for instance can force them to run the risk of incurring these surcharges. Today, highly intelligent systems can anticipate these events on a minute-by-minute basis and rapidly offset incoming utility generated electricity with energy stored in the system. The facility demand remains the same but the supply from the utility is limited to a safe level where peak demand charges won’t be incurred. This can result in enormous savings. The most advanced, intelligent systems such as the Stem product can even help you monitor and manage demand as well as stored supply.

State governments have been very supportive of this. The California legislature, for instance, working with the Governors Office, Energy Commission, and Public Utilities Commission, has passed laws that encourage and often require investment in technologies such as storage. The state’s landmark loading order which consists of “decreasing electricity demand by increasing energy efficiency and demand response, and meeting new generation needs first with renewable and distributed generation resources, and second with clean fossil-fueled generation” is a sign that storage referred to in the order as a “Distributed Energy Resource” has finally come of age.

Storage has grown from the point where once it took a lake, to the point where a population of intelligent products can drastically alter the landscape of supply and demand management, easing of pollution, and ultimately provide for lower costs and a more reliable source of energy for businesses and consumers.


Randy Perretta has spent much of his career in energy data and technology.  He’s currently working in the energy storage industry in Silicon Valley.