Power Plant Resources Affected by Drought
Slightly cooler fall temperatures are putting less strain on power plants to generate energy, but the persistent drought isn’t. Most of Texas’ energy comes from plants that are coal, natural gas, or nuclear. All three types depend on large amounts of water to generate electricity and cool down. If weather experts are correct in predicting a prolonged drought, power plants will need to figure out how to operate with less water.
The water that power plants use is often drawn from rivers that have been drying up since the beginning of the drought last fall. Unless Texas gets at least half of its normal rainfall between now and spring, which isn’t in the forecast, Kent Saathoff said the situation could get worse.
“If that’s the case, then we could have anywhere from 3,000 to 4,000 megawatts of generating capacity reduction going into next summer and that would certainly be a concern,” said Saathoff, who is in charge of electric grid operations and planning at the Electric Reliability Council of Texas.
Reservoir levels at the South Texas nuclear power plant in Matagorda County are approaching those hit in 2009, which were the lowest in state history. According to Buddy Eller, a spokesperson for NRG Energy, one unit at the South Texas Project will be out of commission for a few weeks in October for refueling purposes.
“And then when we have cooler weather, hopefully in the fall or winter, it does slow the rate of evaporation. So it buys us a little bit of time there, too. But at some point, at the end of the year [or] early next year, we may have to draw. We may have to call on some water from the reservoir,” said Eller.
The STP buys its water from the Lower Colorado River Authority, and this would be the first time the plant has asked for its share of the water from the Highland Lakes. Power plants are also subject to curtailments. If water levels in the lakes fall too low, cities and industrial water users could have to cut back by 20 percent.
Michael Webber, an energy policy expert at the University of Texas at Austin, recently published a report on the potential benefits of power plants installing more efficient technology. According to his data, the water that would be saved could equal the amount consumed yearly by 1.3 million people.
“You could switch to dry-cooling power plants or hybrid wet-cooling systems that build in some resiliency against drought, so that’s another approach. You can also look at advanced nanotechnologies to improve the heat capacity of water, so you need less water for cooling. So, there are a lot of options but we have to try them and see what works best,” said Webber.
The developers of the proposed White Stallion coal-fired power plant recently announced it would install a dry-cooling system. White Stallion has had trouble securing enough water to operate. Some of the more efficient technologies would take time to install in existing plants, but Webber says there are also immediate remedies.
“We could use more natural gas tomorrow if we wanted to and need less water, so that’s an option, but people don’t want to do that because it may not make quite as much money, or it might drive up generation costs or something like that,” said Webber.
Coastal wind helped bail out Texas when electricity supplies fell in the summer. Kent Saathoff of ERCOT says he expects more natural gas to be used in the long term, but that an increase in coastal wind would compete with natural gas. This wind blows in the late afternoon when energy demand is at its peak, and doesn’t rely on water.