This is a guest post by Robert Fares, a graduate student at The University of Texas at Austin researching the benefits of grid energy storage as part of Pecan Street Inc.s ongoing smart grid demonstration project. Robert is contributing a series of guest posts discussing grid storage technologies, and how storage could benefit the electric grid. You can read the first and second posts in his series here and here.

During the last days of October 2012, what has become colloquially known as Super Storm Sandy plowed into the eastern United States. The storm was one of the most damaging in U.S. history, causing over 250 fatalities and more than $65 billion in damage. Our fragile electric grid exacerbated the impact of the storm. High-speed winds tore down power lines and flooding damaged electric substations, causing power failures in seventeen states and leaving over one million electric customers without power.

New Jersey and New York were most affected. In New Jersey, over 500,000 PSE&G electric customers and over 400,000 Jersey Central Power & Light customers were without power for more than six days. In New York, over 280,000 Long Island Power Authority customers and over 185,000 Consolidated Edison customers were without electricity for the same period.

The present grids top-down architecture makes it especially vulnerable to storms. Even highly localized damage can affect electricity customers over an entire region. Dr. Alexis Kwasinski, a professor at the University of Texas at Austin, studies how natural disasters affect power and communications systems. His analysis of hurricane Ike shows just how vulnerable the grid is to damage. Although most of the gulf coast region saw little damage from Ike, a vast swath of the region lost power for more than a week after the storm.

Although hurricane Ike did little damage to most of the power system infrastructure in Texas gulf coast region (left), some power outages far from the coast lasted more than two weeks (right).

In Union Beach, New Jersey, hurricane Sandy caused significant damage to homes, but left utility poles intact. Much of the grids infrastructure can endure a hurricane, but minor damage can cause lasting, widespread outages. (Photo credit: Alexis Kwasinski)

Despite its present limitations, the grid is showing signs of a transition to a more distributed and robust architecture. Rooftop solar generation in the United States has grown enormously since 2000. The National Renewable Energy Laboratorys Open PV Project tracks the installation of solar panels in the United States. Its Market Mapper shows the history of photovoltaic installs and prices for all 50 states. To date, more than 168,000 rooftop solar systems have been installed in the United States. The state rankings show that New Jersey and New York have the third and fourth highest number of solar installs, respectively. New Jersey has 7,602 systems installed with a total capacity of nearly 360 MW, and New York has 4,494 systems with a total capacity of 87 MW.

Did New Jersey and New Yorks strides towards a distributed grid make a difference during Sandy? Unfortunately, no. Although rooftop solar survived the worst of Sandy, solar panels dont work when the grid is down. Without the rest of the grid, there is no power to back up deficits in solar production and nowhere to send excess solar power, so solar panels cant provide safe, high quality electricity. Thus, IEEE Standard 1547 forces photovoltaic panels to totally disconnect during an outage.

Adding distributed battery systems to the grid could change this. A number of transformer-level battery systems will be installed in northeast Columbus, OH as part of American Electric Powers gridSmart initiative. In addition to applications like load shifting and frequency regulation, American Electric Powers community energy storage could work with rooftop photovoltaic panels to form microgrids during an electric outage. Transformer-level batteries would charge and discharge to instantaneously balance local solar power production with electric demand, so that intermittent solar generation could be turned into high quality power. Coupled with an energy management system, these isolated transformer-level microgrids could be controlled to power vital loads using available solar electricity indefinitely, or until the rest of the grid recovers.

With many utilities investing in incentives for rooftop solar generation, it would be mindful for them to weigh the costs and benefits of community energy storage. Community energy storage would increase the value of existing solar assets during an outage, and help utilities shift solar electricity production to when it is most needed. Especially in regions like New York and New Jersey, where they are already planning for the next major storm, community storage could work with existing, plentiful rooftop solar to make the grid more resilient, and lessen the impact of the next super storm.

Photo credit: The photos are provided courtesy of Dr. Alexis Kwasinksi, a professor in the Department of Electrical and Computer Engineering at the University of Texas at Austin. Learn more about his ongoing work at his research webpage.

Robert Fares is Ph.D. student in the Department of Mechanical Engineering at The University of Texas at Austin. As part of Pecan Street Inc.s ongoing smart grid demonstration project, Roberts research looks at how energy storage models can be used with large-scale data and optimization for economic operational management of battery energy storage. Robert hopes to develop novel operational methods and business models that help to integrate distributed energy generation and energy storage technologies with restructured electricity markets and retail electric tariffs. Through his research, he hopes to demonstrate the marketability and technical compatibility of these new technologies.