Energy Storage: Out of the Lab and Onto the Grid

Deck: 

As deployments take hold, real-world challenges abound.

As deployments take hold, real-world challenges abound.

Fortnightly Magazine - April 2015

Advanced energy storage is emerging from laboratories and demonstration projects into actual deployment across the power grid. That is evident not only in pockets of activity throughout the United States, but increasingly throughout the world in deployment commitments (in multiple megawatts) by states, island nations, and countries. At the U.S. Department of Energy (DOE) the agency's energy storage database  (a voluntary collaborative list of projects) reports 294 advanced energy storage projects totaling 546 MW already operational the U.S., and a total of 611 projects (1.163 GW) operational worldwide. The industry has come a long way in just a few years.

Nevertheless, when a technology enters the deployment phase, the rules change. In deployment, those demonstrating the technology are no longer just researchers but third-party developers with skin in the game - looking both to operate the technology and operate at a profit. The money propelling deployment will be looking not just to demonstrate, but to earn a return on investment. This fact introduces new challenges and information requirements that may not be readily available to the industry. How do you assess and estimate the cost of operating a system over long periods of time? What is the overhaul and maintenance impact of a system that needs to maintain a rated capacity over a 10-15 year period? Tools are available to help developers understand these costs with confidence, but the industry also needs to realize that despite a terrific success in getting the technology out of the lab, there is still work to be done and support needed to get the technology onto the grid - and to operate there in an effective manner for long periods of time.

A Shift in Thinking

Traditionally, storage devices were categorized either as "power" (short duration) or "energy" (long duration). However, when stakeholders started looking carefully at storage as an application and applying it to the electricity industry, the technologies morphed into a single "concept" that became generic. Although storage consists of many different technologies, ranging from lithium-based, flow-based, and sodium-based batteries, all the way to mechanical systems such as flywheels and traditional systems such as pumped hydro and compressed air energy storage systems (CAES), industry experts began to consider them as one solution. Gone were the subtleties of technology differences - as well as any limits to the potential of a specific technology type. With this perspective, storage was lauded as the "Holy Grail" of new technologies, offering immense promise for the industry. Proponents began to contemplate how it could enhance backup power, balancing of the system, and become a ubiquitous component of our smart energy future.

Figure 1 - California’s Timeline for Storage Procurement

Another key aspect of advanced storage was that the new technologies offered more capability than traditional battery systems. While traditional (lead-acid) storage offered a very limited number of full discharges, the new technologies