Alternative Energy Storage: Enabling the Smart Grid


America’s electric power grid is subject to immense inefficiencies that arise from the interplay between centralized power generation, local power consumption and on demand utility service. To put things into a broad perspective, the nameplate capacity of U.S. generating facilities is about 1 million Megawatts (MW), so if all of our power plants ran 24/7 we would have a theoretical annual generating capacity of 8.7 billion Megawatt-hours (MWh). Since demand for electricity fluctuates on both a daily and seasonal basis, total electric power generation in 2007 was only 4.2 billion MWh, or less than 50% of nameplate capacity. The goal of the Smart Grid is to maximize the efficiency of existing generating facilities and accommodate the integration of renewable power resources. Since many better-qualified authors are writing volumes about transmission and distribution, demand management and renewable power technologies, I’ll limit this article to manufactured energy storage devices; enabling technologies that will be the beating heart of the Smart Grid for the next 10 to 20 years.

Last August I wrote Grid-based Energy Storage: Birth of a Giant, an introductory article that offered an overview of the potential uses for energy storage systems in the electric grid. At the time I confessed that the subject matter was a bit out of my depth, a problem that was compounded by a dearth of third-party analysis on specific applications. Mercifully, all that changed in December 2008 when the Department of Energy’s Electric Advisory Committee (EAC) published two reports that are must reads for investors that want to understand how the Smart Grid will develop, and position their investment portfolios to profit from cleantech, the sixth industrial revolution.

The first EAC report,“Smart Grid: Enabler of the New Energy Economy,” explains how the Smart Grid will use advanced technology to transform the energy production and distribution system into a more intelligent, resilient, reliable, self-balancing, and interactive network that enables enhanced economic growth, environmental stewardship, operational efficiencies, energy security, and consumer choice. The companion report, “Bottling Electricity: Storage as a Strategic Tool for Managing Variability and Capacity in the Modern Grid,” explains why the evolution of the Smart Grid will depend on cost effective energy storage, particularly in the early stages while other distribution and demand management solutions are being developed, adopted and implemented. This report divides Smart Grid energy storage applications into three functional classes: generation; transmission and distribution; and end-user, and then provides thumbnail descriptions of each potential energy storage application. Since my goal is to encourage readers to download and study the EAC reports and other source documents, this article will use summary tables to identify the major application classes and the existing and emerging manufactured energy storage devices that are expected to be useful in those applications.

I’ll apologize up front for giving short shrift to pumped hydro and compressed air energy storage. Both are highly efficient for storing massive amounts of energy and both are subject to physical and environmental constraints that limit where facilities can be built. More importantly, there are no pure-play public companies that focus on either storage technology, so spending a lot of time discussing cool technologies that you can’t invest in seems futile.

One of the most important concepts in any discussion of grid-based energy storage is discharge duration; or the optimal time required for a particular device to release its stored energy. Some grid-based applications require discharge durations measured in hours, others require discharge durations measured in minutes and still others require discharge durations measured in seconds. In general, manufactured energy storage devices that can store large amounts of energy are not good at discharging the stored energy quickly. Likewise, manufactured energy storage devices that can discharge energy quickly do not generally store large amounts of energy. Since the big challenge for utilities is to only provide slightly more power than customers need at any particular moment in time, they have to focus on peaks and valleys, rather than the averages. That’s why a comprehensive solution will require a multi-pronged approach that uses a variety of manufactured energy storage devices to meet particular needs.

The core data in the following table comes from a July 2008 Sandia National Laboratories report on its Solar Energy Grid Integration Systems – Energy Storage (SEGIS-ES) program. While the original Sandia table focused on the current and projected capital costs for manufactured energy storage devices that can be used in solar power projects, the basic cost structure applies to all Smart Grid applications. Since the EAC’s Bottling Electricity report states that the principal purchase decision metrics in Smart Grid applications will be installed cost, reliability, discharge duration and cycle life, I’ve reordered the Sandia data to create a cost hierarchy and provide summary information for each type of storage device. More detailed information on the advantages, disadvantages, commercial status, current research and development and potential applications for each type of manufactured energy storage device can be found in the SEGIS report.

Click for pdf version

The following table is my attempt to integrate the cost and performance data from the SEGIS report with the Smart Grid application information in the EAC’s energy storage report. My goal is to identify the principal technologies that might be useful in each application and highlight the technologies that seem most likely to prove cost-effective. Since the EAC’s report highlights the need for substantial additional research, development and testing to better identify the optimal technology choices, the table is only one man’s informed view through a cloudy crystal ball.

Click for pdf version

At first blush, the percentages of generating capacity that could be satisfied by energy storage systems seem pretty modest, a mere couple of percentage points here and there with higher margins for alternative power installations. But those tiny percentages become massive potential revenue numbers when you consider that the capital cost of energy storage installations ranges from $150,000 to $1.3 million per MWh. Since the principal competitors in the energy storage sector are small compared with similarly positioned companies in other sectors, I believe energy storage is likely to be a veritable investment tsunami that will offer extraordinary returns.

Most of the buzz in the alternative energy sector focuses on renewable power, demand management technology, advanced power transmission systems and batteries for electric vehicles. In the process, the media has largely overlooked the real
ity that energy storage devices are essential enabling technologies for both transportation and the Smart Grid. A number of analysts are predicting that annual global demand for energy storage devices could grow from $25 billion to $100 billion over the next decade. Most estimates of future growth in the automotive market talk about battery sales the $15 to $20 billion range. The much larger growth will come from using energy storage technologies to support the development and evolution of the Smart Grid. While size and weight may matter when it comes to automotive applications, they will be meaningless in grid-based applications where installed cost, reliability, discharge duration and cycle life are the critical metrics.

There are two pure-play public companies in the flywheel sector. Active Power (ACPW) manufactures systems that use low-speed flywheel technology to provide backup power for server farms and a wide variety of commercial and industrial installations. Since Active Power’s technology is modular, scaling systems to provide Smart Grid support should be relatively simple and I expect Active Power to be an early beneficiary of the trend toward grid-based energy storage. Beacon Power (BCON) has recently begun field-testing of utility scale governor response and frequency regulation systems. While Beacon will likely require a couple years of testing before utilities are willing to commence wide-scale implementation of Beacon’s technology, its stock offers significant long-term potential.

There are five pure-play public companies in the advanced lead acid battery group including Exide Technologies (XIDE), Enersys (ENS), C&D Technologies (CHP), Ultralife Batteries (ULBI) and Axion Power International (AXPW.OB). Each of these companies has proven products that can be rapidly integrated into storage systems for the Smart Grid. Moreover, Axion’s pioneering work on lead-carbon devices promises a level of performance, power and cycle-life durability that has not previously existed in the lead-acid world. In addition to its activities in the transportation sector that have resulted in a couple of significant grants, Axion is involved in two utility scale demonstration projects. Since lead-acid is frequently perceived as old-tech, the group trades at a significant discount to comparable companies that focus on other advanced battery technologies. I believe the market valuation metrics will normalize as the Smart Grid opportunities become more widely understood.

There are three pure-play public companies in the lithium ion group that have expressed an interest in the Smart Grid market. Altair Nanotechnologies (ALTI) has shipped a utility scale frequency regulation system for testing and both Ener1 (HEV) and Valence Technologies (VLNC) have taken preliminary steps to evaluate the potential for using their technologies in utility scale applications. Since size and weight are not mission critical issues in utility scale installations, I expect the cost of Li-ion technology to be a significant impediment. However, there are limited Smart Grid applications like frequency regulation that could benefit from extreme high performance batteries.

The only pure-play public company actively involved in the commercialization of Zinc-Bromine flow batteries is ZBB Energy (ZBB) which has recently partnered with Eaton for the global distribution of its flow battery systems.

Foreign companies that have active plans to manufacture products for the utility sector include France’s SAFT Groupe (SGPEF.PK), which has partnered with ABB (ABB) for large-format Li-ion devices, and Japan’s NGK Insulators Ltd. (NGKIF.PK).

DISCLOSURE: John Petersen is a former director of and holds a large long position in Axion Power International (AXPW.OB), a leading U.S. developer of lead-carbon batteries, and also holds small long positions in Active Power (ACPW), Exide (XIDE), Enersys (ENS) and ZBB Energy (ZBB).

John L. Petersen, Esq. is a U.S. lawyer based in Switzerland who works as a partner in the law firm of Fefer Petersen & Cie and represents North American, European and Asian clients, principally in the energy and alternative energy sectors. His international practice is limited to corporate securities and small company finance, where he focuses on guiding small growth-oriented companies through the corporate finance process, beginning with seed stage private placements, continuing through growth stage private financing and concluding with a reverse merger or public offering. Mr. Petersen is a 1979 graduate of the Notre Dame Law School and a 1976 graduate of Arizona State University. He was admitted to the Texas Bar Association in 1980 and licensed to practice as a CPA in 1981. From January 2004 through January 2008, he was securities counsel for and a director of Axion Power International, Inc. a small public company involved in advanced lead-acid battery research and development.


  1. Thanks for the in-depth comparision of the storage technologies, John. It’s exactly for this indepth knowledge of the storage secotr that I recruited you to write for us.
    One technology which should probably be mentioned in a comprehensive article like this one is molten salt thermal storage, but only with the pumped hydro and CAES. Although it’s has the potental for large scale storage at low prices, it only really makes sense in conjunction with Concentrating Solar Thermal Power.

  2. Smart Grid Cars Feeding Back to the Grid
    The battery in the new breed of electric car can both give and receive, taking a charge and then, through the same electrical cord, sending some of its stored energy back to a hungry electricity grid, as needed.
    Supporters see the new plug-in vehicles as a stabilizing addition. They envision thousands or millions of car batteries taking electricity from the grid during low-demand periods, such as overnight, and sending electricity back into the grid at times of heavy demand.
    Better still, the car owners could be paid for the electricity they return, perhaps enough to earn back the cost of the car in a few years.
    Most owners use their cars just one hour a day. In a “vehicle-to-grid” world, “the other 23 hours, that device belongs to the system,” said Jon Wellinghoff, chairman of the Federal Energy Regulatory Commission (FERC).

  3. The EAC Energy Storage report spends a good deal of time on the concept of V2G storage and indicates that the progression will likely be V2B (meaning a building associated with the vehicle) in the medium term and V2G in the long term. Basically the EAC sees V2B in 6 to 12 years and V2G sometime after 2020.

  4. I did similar research a couple years ago, with another possibility being small-scale hydro storage, and thermal storage. For example, in the US West, there are lots of “buttes”, flat topped mountains. Why not build a big storage tank at the top and bottom, and either a pipe, or a drilled hole connecting the two – voila, hydro storage. Quite efficient (70-90% roundtrip), ecological (uses recyclable steel mostly), long lasting, and low tech.
    As to molten storage of electricity (using big heaters in the molten storage tank), round trip efficiency is less, but if it is next to a wind farm, could store energy for peaks. Again, fairly low tech, and lasts forever.

  5. I agree that a lot of the physical storage technologies including pumped hydro, CAES and molten salt can be very attractive, but my focus is storage stocks that people can invest in. So until we get those kinds of technologies into public companies, I’ll acknowledge their existence and the move on to more fertile ground.

  6. Buildings could become the new power plants,and become not simply self-sufficient but also profitable via exporting surplus, which will result in lower cost in the region, according to the analysis.

  7. Do you mean “highly inefficient”?
    I’ll apologize up front for giving short shrift to pumped hydro and compressed air energy storage. Both are highly efficient for storing massive amounts of energy and both are subject to physical and environmental constraints that limit where facilities can be built.
    Author’s note: Pumped hydro and CAES are generally regarded as very low cost and therefore efficient. Finding a place to put them is another story altogether.

  8. I left vanadium redox out of the table because there are no public companies working on the technology. The numbers in the original Sandia table were current:
    20 kWh=$1,800 per kWh to
    100 kWh=$600 per kWh
    With a 10-year projected cost of
    25 kWh= $1,200 per kWh to
    100 kWh=$500 per kWh


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