Research updates on average rate charging

Posted on 09/29/2014 by Ross Baldick
IEEE Austin | RossBaldick.com

Ross Baldick PhD (left) and Steve Pearson, Chairman, IEEE PES/IAS/PELS/IES Austin Chapter

At the recent IEEE Power and Energy Society meeting in Austin, I presented updated work on electric vehicle charging by Mahdi Kefayati PhD, a recent graduate of my UT research group. Building on earlier research results, recent updates include more sophisticated aggregated charging as well as refinements of the average rate charging strategy.

Average rate charging aims to smooth out the effects of large numbers of electric vehicles on the electric grid without any central coordination or communication. It has several advantages for both the electric grid and electric vehicles, but in its simplest form it does not pay attention to some real world issues, such as the need for some range in a vehicle as soon as possible after connecting to a charging station and the potential of drivers to wait to charge until it becomes necessary for completion of the next trip.

In his doctoral work, Dr. Kefayati analyses both of these considerations and shows that they do not greatly affect the fundamental conclusion that average rate charging matches the overall charging power of a large fleet of vehicles to the “valleys” of overall electric load. This means that we could accommodate a large fleet of electric vehicles without large increases in generation or transmission capacity in our electric system and without the complication of central coordination of charging.

Given that wind generators tend to produce their maximum power during the off-peak, average rate charging at home charging facilities will, on average, match charging to when the wind blows, thus facilitating integration of wind resources and the reduction of carbon intensity of transportation.

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More flexibility needed from gas trading

Posted on 04/28/2014 by Ross Baldick

Ross Baldick ConsultingAt the recent Austin Electricity Conference (held at The University of Texas), I chaired a panel session that examined the challenges at the gas-electricity nexus. Gas has been an important fuel for electricity in Texas for decades, but in other countries and in other regions of the US, particularly New England, gas utilization for electricity has only increased relatively recently, and the greater use of gas has already come with some problems.

Gas will become increasingly important for coping with variations in wind and solar, but traditional gas market trading does not match this requirement very well. One of several issues we discussed was the need for the gas industry to move away from “bankers’ hours.” While the gas industry does not need the 24/7 management and real-time control that is necessary for electricity, I believe we need to see gas trading becoming more flexible to support one of its biggest customers: the electricity industry.

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Can Nine Attacks Cause National Blackouts?

Posted on 03/23/2014 by Ross Baldick

FERC | Ross Baldick ConsultingA recent article in the Wall Street Journal, “U.S. Risks National Blackout From Small-Scale Attack,” describes work that the Federal Energy Regulatory Commission (FERC) is doing on the vulnerability of the US power grid. The most disturbing of FERC’s conclusions is that national blackouts can result from attacks on as few as only nine locations.

Research with my colleagues at the Naval Postgraduate School and our students leads me to be skeptical about the very low number of locations that FERC finds sufficient to result in systemic blackouts.

Furthermore, my research-in-progress with Yezhou Wang at The University of Texas at Austin suggests that it would likely take attacks at many more locations to precipitate a complete — as opposed to localized — blackout. This work models cascading outages that can lead to blackouts, in order to more accurately answer the questions that FERC is posing. We aim to better model the effects of failures and attacks, and we are integrating cascading outage analyses into medium- and longer-term models that consider repair times for damaged equipment. An important case-in-point is the time to replace large power transformers.

All that said, the FERC research accurately highlights the fact of the grid’s vulnerability. We need to understand and, where possible, defend the electric grid against those weaknesses.

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