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Feature: Energy Vol. 62, No.11 pp. 13-16
Shaping What’s in Store for the
Next-generation Electrical Grid

Lynne Robinson
About this Issue
JOM in Print
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Wind power, generated by turbines like these along I-80, currently accounts for 14 percent of Iowa’s electricity.
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The workshop report specifically examined the potential grid-scale application of advanced lithium-ion batteries, pictured here, as a means of enabling robust integration of wind and other renewable energies. Additional technologies reviewed in the report were advanced lead-carbon batteries, sodium-based batteries, flow batteries, power technologies, and emerging technologies. (Photo courtesy of Argonnne National Laboratory.)
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Research into enhancing the efficiency of current electrode materials, as shown here, was among the advanced materials focus areas highlighted in the workshop report. (Photo courtesy of Argonne National Laboratory.)
Gary Yang
Gary Yang, Laboratory Fellow
Pacific Northwest National Laboratory
“It was important to gain more information on needs and requirements so that the research community can advance these technologies effectively. We also hope these findngs encourage materials scientists and engineers to turn their attention to this important, emerging area.”
Jay Whiteacre
Jay Whitacre, Assistant Professor, Founder/Chief Science Officer
Carnegie Mellon Univ., Aquion Energy
“The key driver for this technology is to create a solution with a compelling cost at both a $/kWh as purchased and $/kWh delivered over the lifetime of the system. To do this, very scalable, lowcost materials must be used, calendar and cycle life of the device must be very long, and energy must be stored with good efficiencies (> 80%). While the lead acid and lithium-ion systems, among others, may be good for some applications, there is a lack of location agnostic technologies that can economically store energy for between two and eight hours of continuous use over many years without being too expensive or requiring upkeep or replacement. The challenge, then, is to make a scaled system that is at or better than the current lead acid solutions from a capital cost perspective, but with more appealing long-term performance.”
Haresh Kamath
Haresh Kamath, Program Manager, Materials for Grid Transformation
Electric Power Research Institute
“The major obstacles in this area have been high costs, the difficulty of combining value streams, and the lack of experience with storage technology. Many of these obstacles can be addressed only through scale and experience. A national roadmap for investment in energy technologies would help guide researchers toward addressing the real key issues.”
Fernando Garzone
Fernando Garzone, Vice President and Fellow, MST-11 Technical Project Leader
The Electrochemical Society, Los Alamos National Laboratory
“The involvement of multiple societies provided a wide scope of expertise in the field. The Electrochemical Society, for instance, has been dominant in battery, electrolysis, and fuel cell technology for more than 100 years. The ultimate value of the workshop will be to provide scientific consensus-based guidance to federal energy program managers.”
John D. Boyes
John D. Boyes, Program Manager, Energy Storage Systems Program
Sandia National Laboratories
“A key result of the workshop was that the extensive research done in support of vehicle technologies can be applied to only some of the stationary energy storage needs. Large scale (100’s MW), multi-hour discharges are required for many stationary applications. Sodium batteries, flow batteries, advanced lead acid, and liquid metal batteries all have great potential for stationary applications. Electrochemical systems make up only part of the potential stationary storage technologies list; high energy flywheels and compressed air energy storage also can benefit greatly from material science advances.”


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© 2010 The Minerals, Metals & Materials Society


They line Interstate-80 (I-80) in Iowa like immense and stately white birds, their blades rotating silently with an almost hypnotic grace. Besides offering a striking sight to anyone driving this stretch of highway, these and dozens of other wind turbines (Figure 1) installed throughout the state have made Iowa the U.S. leader in terms of the percentage of electricity generated from its abundant breezes, according to an American Wind Energy Association report released in April 2010.

But even in Iowa, the wind can die down or be whipped into a frenzy that overpowers the electrical grid. Smoothing out this variability is a fundamental challenge facing more robust incorporation of wind and other renewable energy technologies into the electricity infrastructure. Zhenguo “Gary” Yang, laboratory fellow at the Pacific Northwest National Laboratory (PNNL), began examining the issue of renewable integration four years ago as part of his work in developing technologies for the “smart grid”—the next-generation electricity delivery network that monitors and manages consumption at an individual consumer level.

The crux of the problem, according to Yang, is the lack of an effective means of storing energy for future use to meet peak demands or compensate for disturbances in the power supply. “There are a number of potential technologies, but their costs need to be reduced to a level which allows for broader market penetration,” he said.

In addition to costs, technical obstacles stand in the way of deploying many promising solutions to the grid scale. Life cycle, operating temperatures, site selection, energy density, and safety concerns are just a few considerations that come into play, regardless of the technology under examination. Adding a layer of complexity is the fact that stationary electrical energy storage (EES), as it is known, is still a relatively unexplored area, Yang noted. “We are still trying to defi ne the needs and requirements for optimal performance,” he said.

Just as one technology will probably not resolve all grid-scale storage issues, Yang said that developing viable solutions requires input from more than one—or even several—scientific and engineering disciplines. Currently spearheading several major energy storage research initiatives at PNNL, Yang said his team draws from a wide range of expertise, including materials scientists, chemists, system engineers, and electrical engineers. Replicating this breadth of knowledge and insight on a bigger scale, he continued, is critical to the development of products with potential to revolutionize the electric grid.

As a starting point for this larger conversation, Yang took on a leadership role in coordinating the Advanced Materials and Devices for Stationary Electrical Energy Storage Workshop, convened by TMS in July. Funded by Sandia National Laboratories on behalf of the U.S. Department of Energy’s (DOE) Office of Electricity Delivery and Energy Reliability and the Advanced Research Projects Agency-Energy (ARPA-E), the workshop tapped into a cross section of perspectives from members of ASM International, the American Ceramic Society, the Electrochemical Society, and the Materials Research Society, as well as TMS.

Framing the discussion were targets for EES in specific grid applications developed by stakeholders from the electric power industry in a complementary workshop organized primarily by Sandia with support from TMS. The workshop end product, Advanced Materials and Devices for Stationary Electrical Energy Storage Applications Report, was published in late October.

“Having five professional societies collaborating on this project significantly broadened its field of view and increased the depth of the discussions,” said John D. Boyes, program manager, Energy Storage Systems Program, Sandia National Laboratories, and workshop organizer. “The outcomes address a wider scope of technologies and possibilities than a more narrowly focused workshop would have. The quality of the report is high and will have broader appeal and usefulness.”

Boyes said that the workshop fit with the DOE’s process of periodically reviewing the status of technologies and science that affect its programs. “My goals for the workshop were to bring together a group of distinguished materials research scientists, present them with the current state-of-the-art and needs of the energy storage industry, and then generate discussions on materials research efforts that could address these needs,” he said. “Those results are being used in formulating the DOE’s long-term program plan.” Yang said that the workshop was the first project of its kind “to explore technologies from the materials side.” He noted that rather than generating new concepts, participants focused primarily on finding gaps in existing approaches and pinpointing advancements that could help reduce costs and make the technologies practical.


While all energy storage technologies and systems were fair game for discussion among the 35 workshop participants, emphasis was placed on solutions that could be realistically deployed at the grid scale with DOE involvement in a relatively short time frame—present day through 2030, with particular emphasis on the one-to-five year and five-to-10 year time blocks. Initiatives were examined within the context of three guiding principles:

  • Informed Materials Selection:
    As the size of storage devices is scaled up to meet the needs of the grid, it is crucial that storage devices utilize materials that are lower in cost and abundant in the United States.
  • Efficient Materials Utilization:
    Better understanding of the materials being used can lead to improvements in device response time, capacity, operational efficiency, and lifetime.
  • Innovative Designs:
    If a storage technology design is too complex, it will be difficult for lowercost automated manufacturing and quality control processes to be put into place. System design also ensures that control systems and power electronics enable efficient, secure, and reliable interoperability with the electric grid.

As noted in the workshop report, any stationary EES technologies under consideration must meet critical economic, performance, and design targets if they are to provide maximum benefit to consumers and acceptance by the power industry. Of these, system economics is the most important metric to the electric power industry. The report emphasized that, in order to be implemented at grid scale, the cost of stationary EES devices overall will have to be reduced to between onethird and one-half of the cost of current technologies.

In addition to lowering costs, the report also noted that advanced technologies must exceed performance when compared with currently available technologies to ensure widespread adoption. A final critical metric highlighted in the report was system design—not only must systems be able to demonstrate low cost and high technical performance at the grid scale, they must also meet the safety standards of the electric power industry.

Using these key metrics and guiding principles as a basis for decisionmaking, the workshop participants identified the following EES technologies as offering the greatest potential for near-term grid-scale deployment: high-speed flywheels; electrochemical capacitors; traditional lead-acid batteries; advanced lead-acid batteries with carbon-enhanced electrodes; sodium sulfur batteries; lithium-ion batteries; zinc-bromine batteries; vanadium redox batteries; compressed-air energy storage; and pumped hydro.

The workshop report also presented cost and performance targets for five storage applications that, if advanced EES technologies were implemented, were determined to have the greatest potential to benefit power system planning and operations. They were:

  • Area and Frequency Regulation (Short Duration):
    Reconciles momentary differences in supply and demand within a given area.
  • Renewables Grid Integration (Short Duration):
    Offsets fluctuations in renewables generation output and accommodates renewables generation at times of high grid congestion.
  • Transmission and Distribution Upgrade Deferral (Long Duration):
    Delays or avoids the need to upgrade transmission and/or distribution infrastructure and reduces loading on existing equipment to extend equipment life.
  • Load Following (Long Duration):
    Changes power output in response to the changing balance between energy supply and demand and operates at partial load without compromising performance or increasing emissions.
  • Electric Energy Time Shift (Long Duration):
    Stores inexpensive energy during low demand periods and discharges the energy during times of high demand.

“While the metrics and targets will vary depending on the specific energy storage technology or device and the location of the application,” the report noted, “they can serve as guidelines for researchers and the electric power industry to assess the value of individual technologies.”


The balance of the workshop report delineated limitations of current EES options, while also providing technology-specific timelines for priority initiatives that explore the potential of new and current materials to overcome those limitations. Specific EES technologies reviewed include:

Advanced Lead-Carbon Batteries
Originally developed as an inexpensive power option for hybrid electric vehicles, these batteries incorporate carbon-enhanced electrodes to improve upon traditional lead-acid battery technology, while still maintaining low system cost. To overcome issues regarding energy density, system size, electrolyte stratification, cycle life, and maintenance requirements, the report emphasized efforts in electrolyte advances, electrode development, and diagnostics and modeling.

Lithium-Ion Batteries
Despite the widespread use of Liion batteries (Figure 2) in electric vehicles and electronics, the grid-scale application of these devices is currently limited, largely due to concerns involving safety, lifetime and cycle life, cost, battery management, and materials performance. Among other recommendations, the report suggested that research strategies focus on developing inorganic electrolytes to improve performance and safety, while also gaining better quantitative understanding of cell failure through experimentation and modeling.

Sodium-Based Batteries
One of the most mature, commercially available EES technologies, these batteries are composed of molten sodium and sulfur electrodes, with a solid electrolyte membrane in between to facilitate the transfer of ions and electrons. However, issues involving chemistries, materials, battery design, manufacturing and stack design, and controls and monitoring must be addressed before sodium batteries can function at grid-scale storage levels.

The report recommended utilizing surface science techniques to identify and understand impurities on sodium battery anodes and cathodes as a path to reducing costs and increasing reliability. Other priority activities centered on developing robust planar electrolytes to decrease stack size and resistance, as well as identifying low-cost materials for encasing high-temperature cells, lowering operating temperature, and implementing cost-effective manufacturing processes.

Flow Batteries
Flow batteries, such as zinc bromine and vanadium redox batteries, provide independent power and energy because of their flexible storage durations. These devices consist of electrolytes that flow from an external electrolyte storage tank and past an electrochemical cell. They typically depend on a membrane to facilitate the flow of ions between electrolyte solutions in two separate tanks. The report suggested that significant advances in enabling flow batteries to function at grid-scale storage levels could be achieved through such efforts as improving membranes to reduce electrolyte crossover; improving efficiency by identifying low-cost anti-catalysts and redox catalysts for negative electrodes and developing non-aqueous flow battery systems with wider cell operating voltages; and exploring low-cost chemically and thermally tolerant resins for piping, stacks, and tanks.

Power Technologies
Providing short, real-time pulses of power to ensure consistent frequency and voltage, this group of technologies is known for quick response and the ability to be cycled tens of thousands of times. Both flywheels, which generate power by using a motor to rapidly rotate a cylinder supported by magnetic levitated bearings, and electrochemical capacitors are currently being developed, tested, and demonstrated for grid-scale power applications. The report noted, however, that electrochemical capacitors have a low energy density, while the electrolytes in current designs have high wetting with low voltages and are potentially flammable. Materials research is also called for in enabling flywheels to achieve a density closer to their theoretical potential and to address the mechanical stresses typically placed on their structures.

Emerging Technologies
Metal-air batteries, regenerative fuel cells, liquid-metal systems, and adiabatic compressed air energy storage are all in a nascent stage of development, but according to the report, have potential to improve the stability and resiliency of the electric grid in the long-term. Targeted research and development, incorporating a variety of technology-specific and cross cutting activities, should address such areas as materials performance, life cycle testing, degradation analysis, and cost-effectiveness.

While each storage technology has its own specific limitations and potential solutions, the report presented several key advanced materials focus areas that could significantly encourage commercial success across the board. Basic materials research, for instance, needs to surface more effective, safer, inexpensive, and robust electrochemical materials combinations, as well as explore readily available materials such as iron, aluminum, magnesium, and copper for use in EES technologies.

More efficient utilization of current electrolytes and electrodes (Figure 3) also have the potential to increase conductivity, amplify capacity, reduce resistance, improve thermal tolerance, and extend the life of energy storage devices. Engineering electrolytes into thin and flexible crystalline solids likewise offers an opportunity to increase efficiency compared to systems with liquid electrolytes. Improved membranes and seals to help limit contamination and nanomaterials that can lead to development of high-power and quick-response energy storage devices also factored in the report’s suggested strategies for technological advancement.


Another common denominator with all of the technologies explored by the workshop participants was the need for more experience in application of EES technologies at scale. Said workshop participant Jay Whitacre, assistant professor, Carnegie Mellon University and founder/chief science officer of Aquion Energy, “One of the biggest issues with this technology is the vast scale necessary to even prove out valid ideas. Taking a simple novel battery chemistry that has not been scaled before, and proving that it can be manufactured at MWh/year scale is both very expensive and laden with risk from an investment standpoint. To innovate at this scale, a new way of supporting energy storage specifically and energy technologies in general needs to be developed.”

Yang said the workshop marked an important step in the formulation of a more focused, coordinated approach that will hopefully facilitate the evolution of stationary EES technologies in the future. “Creating these initial requirement matrices, from the standpoint of advance materials engineering, was critical,” he said.

Boyes agreed that the output from the workshop has helped clear a path leading to the development of nextgeneration EES devices. And while no “silver bullet” solutions were identified, the participants’ engaging in “very open and frank discussion around the needs, state-of-the-art, and where their own research might apply” was extremely valuable in building momentum for future activity. He commented, “Many participants left with new ideas and possibilities in mind: ‘I wonder if this might work.’”

Lynne Robinson is a news and feature writer for TMS.