Grid-scale energy storage gets Senate scrutiny
This morning, the U.S. Senate Committee on Energy and Natural Resources is set to receive testimony on the role of grid-scale energy storage in meeting the country's energy and climate goals. As they are hearing from industry witnesses including KEMA's Ralph Masiello, the National Renewable Energy Laboratory's Robert McGrath, PJM Interconnection's Ken Huber, and Bonneville Power's Elliot Mainzer, I thought it appropriate for us to take a closer look at what has been called the "missing link" of electric power generation.
A quiet, gentle giant on the horizon of the emerging intelligent utility, grid-scale energy storage has been receiving a lot of public attention recently, with the announcement just scant weeks ago of 16 Smart Grid Demonstration Grant awards for a total of $185 million in stimulus monies to help fund utility-scale storage projects designed to ultimately enhance the reliability and efficiency of the grid, while reducing the need for new electricity plants. As we continue to add more renewable (and intermittent) energy resources such as wind and photovoltaic systems to the mix, the addition of energy storage at these installations (and elsewhere along the grid) will allow improved frequency regulation and peak energy management overall.
When I say "giant", I truly mean giant. Some have even referred to energy storage as the "Holy Grail" of electric power generation. Estimates project the electric utility energy storage market to top $2.5 billion by 2015. An Energy Business Report on trends and opportunities for energy storage in the utilities industry, published in October, even before the stimulus funding announcement for 16 different demonstration projects, indicated that eight technologies -- batteries, compressed air storage, flywheels, hydrogen, superconducting magnetic energy storage, thermal energy storage, ultracapacitors, and vehicle-to-grid -- will be competing in this market.
The Department of Energy's selections for demonstration projects include advanced battery systems (including flow batteries), flywheels, and compressed air energy systems. Southern California Edison, for example, plans to deploy and evaluate an 8 MW utility-scale lithium ion battery technology in the Tehachapi Wind Resource Area, where the first phases of the utility's Tehachapi Renewable Transmission Project are currently being built. In Chicago, Illinois, Beacon Power Corporation plans to design, built, test, commission and eventually operate a utility-scale 20 MW flywheel energy storage frequency regulation plant, and provide frequency regulation services to its grid operator, PJM Interconnection. The New York State Electric & Gas Corporation plans to demonstrate a 150 MW compressed air energy storage technology plant using an existing salt cavern. And that's only three examples of some highly innovative projects receiving federal government-matched funding.
But there are several other grid-scale energy storage options also being tested and/or already in place across the U.S., as well. Take, for example, Colorado-based Ice Energy's thermal energy storage system, which takes advantage of thermally efficient nighttime power to produce and store energy for daytime use by air conditioners, traditionally considered an "energy hog" and the single largest component of peak energy consumption.
According to David Shpigler, the president of utility-focused strategy management-consulting firm Shpigler Group, who led an Energy Central webcast yesterday about making the business case for utility-scale distributed energy storage, the value proposition for each electric utility will be different in each and every case. "Storage by itself is nice," he said, "but it can also support a number of different programs, and each needs to be looked at in isolation."
Shpigler told us the smart grid offers a tremendous amount of opportunity for grid-scale energy storage. "It can improve asset utilization through peak shaving, enhance reliability through distributed backup, and much more," he said, adding other points as well, including reducing line losses, a tremendously important issue if you look at the losses inherent in every portion of the generation-to-consumer connection.
I, for one, will be listening in on the Senate hearing closely today. I'll let you know what I find out.
I look forward to discussing this and other issues with all the players in the emerging intelligent utility. If you have a story to tell me, or thoughts you'd like to share, please contact me by e-mail at krowland@energycentral.com or by telephone at 720-331-3555.
Comments
Grid-Scale Storage
Storage at any scale offers a variety of benefits to the grid. However it's not the only technology that can provide most of those benefits, it may not be the most cost-effective technology, and some storage technologies may actually exacerbate certain kinds of problems.
For storage to be cost-effective, it must be able to earn its keep. This means the sum of all market revenues for ancillary services, load following, regulation, capacity payments, and time-shifting cheap off-peak energy must be sufficient to pay the capital and operating costs of the plant. Ancillary services and capacity payments may be enough, but very large energy price differentials are required over a substantial number of hours before time-shifting energy provides enough margin to pay for storage. In studies my colleagues and I performed for EPRI nearly two decades ago, Compressed Air Energy Storage wasn't viable unless the average on-to-off-peak price differential was at least 2 to 1. Conventional pumped storage plants would likely require somewhat larger differentials.
In California, there's increasing concern about the ability of the grid to withstand disturbances when renewable energy reduces the amount of conventional generation and attendant intertial response capablity that is synchronized to the grid. Unfortunately, batteries exacerbate this problem, while conventional pumped hydro plants that could help mitigate the problem are difficult to site and build.
I happen to think ICE Energy's product isn't getting the attention it deserves. Air conditioning puts more stress on the grid than perhaps any other end-use technology. Thermal storage would allow the electric load associated with cooling to be spread over a longer time interval, reducing the need for peaking capacity that's typically used during only a handful of hours each year and improving the utilization of expensive base load power plants.