Energy Reservoirs in Your Backyard

by Dick DeBlasio, IEEE P2030 Work Group

Of the many ongoing smart grid conversations, most still focus on what will be novel about the new regime for power distribution and generation.

Deciding which emerging renewable technologies will be used, how information will be exchanged across the grid and what networking technologies will be adopted all are indispensible topics for discussion.

With the focus on renewable sources and information exchange, however, more mundane affairs such as what happens to the power being distributed might not get their fair share of attention. One traditional power technology, in particular, will have an enormous impact on the smart grid’s efficiency, as well as on the architecture of information technology, communications and the methodology adopted for allocation: large-scale energy storage.

When the equivalent of gigawatts of power can be stored, the full potential of off-peak generation at last can be realized. A large-scale, reliable, efficient and most likely hybrid energy storage infrastructure also will be a great boon to renewable energy producers who have little control over the natural forces they harness to create electricity.

Much energy will be stored. A GTM Research report estimates that in the U.S. today the energy stored for mitigating short-term supply disruptions is just 49 MW, most of it in the form of pumped hydropower. GTM forecasts this will rise to 479 MW by 2015 and that total storage capacity could peak at 7,317 MW in the U.S. and 37,828 MW worldwide. More significant, GTM estimates that a mature market for storage technologies could be 450 GW worldwide and 85 GW in the U.S. (See “Grid Scale Energy Storage: Technologies and Forecasts Through 2015,” an August 2008 report for GTM Research by John Kluza.)

A geographically diverse, hybrid and enormous energy storage infrastructure, however, probably will bump up the complexity of the system by an order of magnitude for the smart grid’s information technology and networking components.

What’s Old is New

Storing energy for future conversion into electric power is not novel. Holding water behind dams to generate hydroelectric power has been around more than 150 years. Pumped storage is a more recent and less efficient alternative to simply harnessing the power of gravity. Batteries are hardly new, either. Alessandro Volta invented the first wet-cell battery in 1800, and there have been hundreds of major innovations in electrochemical energy conversion since then.

Nevertheless, things have changed. In most parts of the world, dams are not seen as the unalloyed benefit they once were. Depending on their chemistries, batteries might fare somewhat better on the scale of environmental sensitivity, but projects funded in the 1990s using lead-cell batteries for large-scale storage proved economically unfeasible.

Pumped storage and batteries still deserve to be part of the mega-storage equation, as do compressed air and flywheels, which the Department of Energy has funded for demonstration projects. Still in the research phase but with undeniable potential are supercapacitors, heat engines and fuel cells.

Light Bulbs or Holistics?

So far, the smart grid’s energy storage challenge has followed a predicable path that could be characterized as the lightbulb theory of technology progress. Corporations or academics and the government get a bright idea and pursue it with unbridled, entrepreneurial zeal.

It works well most of the time. The lightbulb approach tends to lead to tunnel vision, however, and produces a collection of siloed solutions. It also can create a competitive environment in which defeating your competitor–not solving the problem–becomes the paramount goal.

The lightbulb approach will contribute to the overarching goal of creating an optimal high-capacity energy storage system because new technologies must emerge and existing technologies must be modified and fine-tuned.

An equal or greater contribution to the goal can be realized with a holistic approach that leverages the energy storage resources already there or, more accurately, will be there once the smart grid is a reality.

The advantage of a holistic approach is simple: Not much new needs to be invented, manufactured or deployed. The holistic contribution to the solution is virtually free. It will not be the whole solution–new technologies will and should be deployed–but it could reduce smart grid implementation costs.

Energy Reservoirs in Your Backyard

The first storage resource to be considered is the storage capacity of electric vehicles. The University of California at Berkeley’s Center for Entrepreneurship and Technology forecasts that electric cars will account for 64 percent of U.S. light-vehicle sales by 2030 and will comprise 24 percent of the U.S. light-vehicle fleet.

The second is microgrids, the generation and distribution systems sourced primarily by local producers for renewable energy, whether it is wind turbines or rooftop solar panels. Storage external to the microgrid is critical to green energy producers because it provides a reservoir for excess generation when the wind blows or the sun shines.

When the renewable energy source is idle, the storage capacity inside the microgrid could become a reservoir in which utilities can store energy they generate at low cost during off-peak hours or whenever the microgrid requires it.

Using distributed, pre-existing storage capacity is a radical idea because until now the renewable energy concept assumed power would flow from the microgrid into the public utility’s grid.

Making it Work

In October the Institute for Electrical and Electronics Engineers (IEEE) announced the formation of the P2030.2 Working Group to define smart grid energy storage systems. Also known as the Large Scale Storage Working Group, it will deliver guidelines for discrete and hybrid energy storage systems integrated into the electric power infrastructure.

The working group’s guidelines should be complete in about two years. The full spectrum of energy storage technologies and options will be studied, as well as the challenges of managing and integrating them into a hybrid system.

The government also recognizes the importance of storage. In November 2009, the DOE announced $185 million in grants for 16 energy storage projects.

The DOE’s Storage Systems Research Program is collaborating with more than 20 projects, including nearly $10 million of grants with the California Energy Commission and nearly $6 million for six projects with the New York State Energy Research and Development Authority.

Several demonstration projects using compressed air have been funded, including projects managed by California utility Pacific Gas & Electric Co. that will be capable of storing 300 MW for 10 hours. Others include SustainX Inc. in New Hampshire (1 MW for four hours) and New York State Electric and Gas Corp.’s 150 MW project in Watkins Glen, N.Y. One flywheel, two wind energy storage and eight battery demonstration projects have been funded.

A community energy storage (CES) demonstration project managed by DTE Energy Co. will test the viability of using electric vehicle batteries as secondary-use storage for the smart grid. The project calls for 20 CES units each storing 25 KW for two hours. The CES microgrid also will be integrated into a solar-generation system.

Project goals include demonstrating capabilities such as voltage support for the grid, integrating renewable generation, islanding during outages and frequency regulation. The project also might identify options for reducing electric vehicle cost and suggest how CES devices and control algorithms can be standardized throughout the U.S.

Less Can be More

Fueled by global warming revelations, advances in communications technologies such as Broadband over Power Line (IEEE 1901) and the desire to reduce energy dependence, the smart grid has moved from concept to large-scale demonstration projects in fewer than five years. The industry is determined to see continued, rapid progress.

As the funding of the DOE’s demonstration projects illustrates, however, government and industry might be overlooking a potent contributor to a large energy storage infrastructure by funding a single CES project. The implications of minimizing or disregarding CES in the short term only to revisit its value later are far-ranging.

As the information technology and communications infrastructures develop, for example, they should accommodate the distributed nature of CES in which many small-scale energy storage avenues, when combined, represent a large-scale contribution that must be managed. Public utilities should recognize the CES option as a way to reduce their capital expenditures and condition power on the grid.


In addition to his role as chairman of the IEEE P2030 Work Group, Dick DeBlasio is a member of the IEEE Standards Association Board of Governors and chief engineer with the National Renewable Energy Laboratory, Reach him at


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