Battery Technology and the Electric Power Grid and Unreliable Power Sources

Michael Giberson

The Christian Science Monitor recently ran a story on battery technology and the electric power grid. I’m not sure that there is much new there for anyone who is already paying attention to energy storage issues in bulk power, but the story provides a decent overview.

AN ASIDE: I’m am always mildly amused when the February 26, 2008 wind power drop-off in Texas is cited as an example of the reliability challenges associated with wind power, at least when the stories omit any mention of the nuclear power drop-off and blackout in Florida on the same day.

As the CSM story mentions, over a three-hour period “wind power output [fell] by 1,400 megawatts” in Texas. (More background here.) In Florida that same day, an early afternoon fire at a FPL substation led to transmission problems, leading several power plants to shut down (including two nuclear reactors and a number of natural gas plants).  All told, Florida lost about 2,500-megawatts of incoming electricity in a few moments (not 1,400 megawatts in a few hours).

It is much more expensive to build and operate a power system capable of withstanding the Florida-kind of problem as compared to the Texas-wind problem, which is why Texas was able to avoid a blackout with the equivalent of a few phone calls, while in Florida schools, stores, and other businesses closed early, traffic backed up due to traffic signals losing power, and perhaps 2 million people were without power for several hours.

3 thoughts on “Battery Technology and the Electric Power Grid and Unreliable Power Sources

  1. Mike,

    I agree completely. Apples and oranges are not the same.

    ERCOT West even experiences negative power prices when available wind power cannot be “schmeared” thinly enough because of insufficient transmission interconnection.

    There were probably wind turbines trying to deliver power when the Northeast transmission grid failed several years ago.

    Yes, both issues are reliability issues, but of a very different type. You suggest that Texas has managed to “wind proof” its grid to a degree. However, I doubt they have “idiot proofed” their grid anymore than Florida had or has.

    It will obviously become progressively more critical to be able to forecast wind availability and respond to low availability events as wind becomes a higher percentage contributor to the generation fleet capacity, even with the introduction of mass storage.

  2. I think I see your point, Mike. From your description it sounds as if the Florida event was a multiple contingency, the kind that planners don’t really plan for. That is probably true even though the event trigger was in one substation, because I think planners would consider only one or two components at a time as a planning contingency, not the loss of everything in the substation. When multiple simultaneous contingencies happen, the system may be in an unknown and unanalyzed condition. With luck it’s not critical, but some multiple contingencies will cause blackouts. You’re right that it would be much more expensive to cover such low-probability problems, and the standards for planning and operations are not set so stringently as to prevent loss of load in some locations when such events occur. A multiple-contingency outage is news, but it is a reliability issue that the industry long ago made a conscious decision not to plan for.

    In contrast, 1,400 MW over several hours doesn’t really seem like it would be very difficult to work around in a system as large as ERCOT, unless it were in a condition of scarcity. Besides, the system has to be able to withstand losing a South Texas unit at any time, and that’s over 1,200 MW in a few moments, and the system is supposed to be able to re-establish operating reserves within 15 minutes of that event. So the wind event should have been minor, just from a capacity point of view, and not really newsworthy. There is the question of how likely a 1,400 MW wind event is, and whether it could occur with enough speed to really challenge operators. If such an event is as likely as any other planning contingency, then operating standards should be set to be able to withstand it. If likely events are not covered by operating standards, then such events will be newsworthy and troublesome, and we’d better plan for them. I suspect that ERCOT has it covered, although the problems will intensify with greater penetration, as Ed points out.

  3. It seems to me that it is a category error, to compare the rare failure of a system that is designed to work 24/7 with the ordinary operation of a system which is designed to work less than all of the time.

    Wind and solar cannot by their natures operate 24/7, they must have back-up systems. The back systems are expensive, particularly, because they will be used only part of the time.

    Until such time, if ever, as those costs are specified, we cannot know how much reliance on “renewable” energy will cost.

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