The Electric Reliability Council of Texas, which manages the power grid for about 90 percent of the state, expects summer heat this year to push system demand past the safety cushion the council tries to maintain. But its weather forecasts don’t call for the extremes the state experienced in summer of 2011, when the council issued several emergency alerts but never had to resort to rolling power blackouts. (The last rolling blackout occurred earlier in 2011 — and resulted from generator problems during a February cold snap in a year better remembered for its sweltering, dry summer.) Warren Lasher, director of system planning for the Electric Reliability Council of Texas, spoke with FuelFix recently about the system’s reserve margin and how the public can help the grid meet the power demand. Edited excerpts:
FuelFix: Why is it important to maintain a capacity reserve margin for the electric grid?
Lasher: It is important for dealing with issues that we don’t see today — things that can happen that we can’t predict. Excess generation is a buffer. It is additional capacity that we can use in case something happens that we don’t know about. The electricity system is a just-in-time system. When we use the energy, right at that moment the energy is being produced somewhere on the system. The transmission system moves that power almost instantaneously from a generation plant to a load. So when someone turns on a light or a blow dryer, right at that very minute, a power plant has to increase its output in order to serve that additional load. There is no way for us to store that energy that is not used one day for the next day.
FuelFix: How did the hot summer of 2011 affect the agency’s estimate of how much electricity generation capacity would be needed in the system in the future?
Lasher: We have a 13.75 percent target reserve margin, which means — above and beyond our load forecast — we would like to have 13.75 percent reserves in order to maintain the reliability of the system. Once you factor 2011 into that same consideration, that target reserve margin looks like it needs to increase. These possible increases are now being discussed with stakeholders.
FuelFix: If the margin drops below 13.75 percent, does that mean there will be rolling blackouts?
Lasher: What it means is that the risk of rolling blackouts would increase. The 13.75 percent is designed to match up with a one-event-every-10-years standard. The expectation would have to be that if you are below 13.75 percent, then your risk of an event would be greater than one in 10 years — it could be one-in-eight-years or one-in-six-years. Because we can’t predict the weather, it is all a matter of risk.
FuelFix: If an event occurred this summer, what would you look for customers to do to help lessen the stress on the electric grid?
Lasher: Customer participation can really support the reliability of the system. On the peak hours of the hottest days of the summer, if consumers can reduce their actual usage of electricity — for example, turning up the air conditioning a couple of degrees, not running laundry machines or pool pumps — it helps tremendously. The peak time for electricity usage is 3 p.m. to 7 p.m. on weekdays, when industrial customers are operating. Anything consumers can do on those high-demand days to reduce usage can support the reliability of the system.
FuelFix: Does the grid manager tell generators what kind of electricity, say, coal or nuclear or wind, it prefers to use?
Lasher: The Electric Reliability Council of Texas is not involved in deciding what kind of power plants get built. The generation plants built in our system are based on independent investors deciding what they think will make a profit in the market.
FuelFix: If natural gas prices are cheap right now, why aren’t we just building natural gas plants in Texas, instead of trying to use wind, nuclear and coal generation as well?
Lasher: Every source of energy comes with its own risks and its own considerations. Natural gas right now is inexpensive and plentiful, but that has not always been the case. The natural gas market is volatile, so the expectation has to be that sometime in the future, prices will rise and then they will fall again. All the different types of power plants have their own strengths and weaknesses.