This post has been updated.
The Electric Reliability Council of Texas has asked people to conserve energy throughout the week as the supply of electricity on the Texas grid ran the risk of falling short of demand.
Texans should reduce their electricity use through Friday, ERCOT said.
It is the second time the state’s grid operator has made such a request since devastating blackouts gripped Texas in February.
ERCOT blamed the tight grid conditions on the fact that four times more electric generators than expected were shut down for repairs.
On Monday, the grid operator said over 12,000 megawatts of generation capacity — about the amount of energy it takes to power 2.2 million homes on a summer day — is unavailable because of those forced outages. One megawatt of electricity can usually power about 200 homes on a summer day.
According to ERCOT, about 75% of that unavailable power comes from “thermal” generators, typically gas and coal plants and nuclear plants, being offline.
“We are deeply concerned about the issue associated with all of these plants that are offline at this time, and we will be doing a thorough investigation,” said Warren Lasher, ERCOT’s senior director of system planning, during a media call Monday.
Generator owners have told ERCOT the number of outages should decline by the end of the week.
High electricity demand is adding to the pressure on the grid, as cities across Texas expect temperatures in the 90s or higher this week. The state broke its June electricity demand record Monday, with Texans pulling over 70,000 megawatts of electricity from the grid.
In the media call Monday, ERCOT provided few answers about what power plants were offline and why.
Lasher repeatedly said he did not have information “available” on which plants were offline and why. ERCOT often does not share some of that data, saying it could violate competitive secrets of power plant owners.
Lasher also said he would not “speculate” on the question of whether market manipulation may be to blame. ERCOT’s independent market monitor is charged with investigating fraud on the grid.
When supply and demand for electricity fall out of balance, the electric grid runs the risk of completely failing. In that scenario, hardware essential to the generation and transmission of electricity breaks down and the entire grid goes dark.
ERCOT officials have said re-energizing the state after such a collapse could take weeks. That is one reason they resort to planned blackouts to restore balance on the grid, viewing it as preferable to what they often refer to as "catastrophic failure" of the grid.
ERCOT's latest request for conservation is bound to increased calls for an overhaul of how Texas runs its grid. In this year’s legislative session, lawmakers passed a series of reforms aimed at safeguarding the state against blackouts.
At a signing ceremony last week, Gov. Greg Abbott said that “everything that needed to be done was done to fix the power grid in Texas.”
But grid experts have warned that the risk of big blackouts remains unless the state does more to overhaul its deregulated energy market and provide more backup power in times of emergency. They say that risk will only increase as the temperature rises, unless more electric generators are brought back online.
“I shudder to think what things would be [like] if we were actually having a heat wave,” said Dan Cohan, a civil engineering professor at Rice University, after a similar call for conservation was released during relatively mild weather in April.
To avoid the need to institute blackouts, ERCOT offered Texans these tips to help conserve power:
- Set thermostats to 78 degrees or higher.
- Turn off lights and pool pumps.
- Avoid using large appliances like ovens, washing machines and dryers
- Turn off and unplug any device not currently in use.
San Antonio's utility CPS Energy said all of its plants are up and running, and most are at full capacity, as of 2 p.m. Monday.
CPS suggested similar methods of conserving energy.
