On April 21, 2011, NAATBatt and the U.S. Department of Energy will hold a workshop for industry stakeholders on one of the most revolutionary if underappreciated technologies in the cleantech/smart grid field:  distributed energy storage.  Distributed energy storage, or DES, describes the practice of locating stationary batteries, generally 25-50 kW in size, on the premises of electricity customers or immediately proximate to them.  Residential energy storage, community energy storage and vehicle-to-grid systems are all examples of DES systems.  DES systems can use the same types of batteries that power plug-in electric vehicles.

Adding the ability to store electricity to the grid is an important part of making the grid smarter.  Stored electricity can be used to provide the load following reserves necessary to balance and integrate variable renewable energy onto the grid.  It can also provide other ancillary services to grid operators, such as voltage support and spinning reserve. DES is one of several energy storage technologies that can provide these benefits.  Other technologies include hydro storage, compressed air energy storage, flywheels, and large scale flow and sodium sulfur batteries.

What distinguishes DES from other storage technologies, and what makes DES so potentially important to the smart grid, is its ability to provide a virtual form of demand side management.  Demand side management, or DMS, is the central function of many smart grid systems.  The goal of DMS is to encourage consumers to use less electricity during peak hours, or to move their time of energy use to off peak hours, such as evening or weekends.  By leveling electricity demand, or matching it more closely to the times that renewable energy is generated, the grid becomes cleaner and more efficient.

DES provides virtual DMS by effectively replacing the electricity consumer with a battery.  A grid operator wheels power to the DES battery when it is convenient for the grid operator to do so.  This will generally be during off-peak hours when the wind is blowing or the sun is shining.  The traditional electricity consumer no longer has a relationship with the grid, other than as a source of back-up power.  The consumer’s relationship is with the DES battery, which provides the consumer with power when the consumer wants it from a source that is at its farthest right next door.

The elegance of the DES solution becomes particularly clear when contrasted with other forms of smart grid technology that provide DMS.  Some of those technologies garner the lion’s share of attention and smart grid funding.  The federal government spends billions of dollars subsidizing smart meters, new utility billing systems, and the creation innovative electricity rate structures.  The funding is provided in the hope—and it is only a hope—that retail consumers will change their electricity consumption patterns in response to relatively mild price signals.  DES changes consumption patterns more certainly, and can shape them with precision, simply by dispensing with the traditional electricity consumer and replacing it with a battery. 

The ability of DES systems to provide virtual DMS is only part of the story.  DES systems also provide consumers with a useful form of back-up power, an easy way to put electricity produced by distributed generators (e.g., solar rooftops) onto the grid, a way to reduce the privacy concerns to which smart meters give rise, and a huge potential market for lithium-ion batteries, which could create economies of scale for advanced battery manufacturers and dramatically reduce the cost of plug-in electric vehicles.

So with billions of dollars being invested in smart grid technologies, why does DES technology live in relative obscurity and appear to have been consigned by government and industry to Death by Demonstration Project?  Clearly the guy who said that the world will beat a path to the guy who invents a better mousetrap never worked in the power industry.  It is frustrating to see DES developers, who have answered the call to think outside the box with respect to the grid, sitting on the sidelines while other, more challenged technologies get funded and deployed.

The reasons why the game-changing potential of DES systems is being overlooked are difficult to identify.  The complexity of deploying DES systems onto the highly and disparately regulated distribution portion of the grid is certainly one factor.  The traditional conservatism of the utility industry is probably another.  More insidiously, the fact that DES systems might make smart metering retail consumers less urgent, and threaten the ability of some to capture and sell consumer data, may account for some of the lack of enthusiasm.

The workshop in Chicago on April 21 will try to identify the challenges to DES system deployment and propose a way forward.  More information about the April 21 workshop can be found a www.naatbatt.org.  Following the link for information about the DES Workshop.