At 1:25 a.m. Monday morning, the Electric Reliability Council of Texas (ERCOT) initiated rotating outages. In its release, ERCOT stated 30,000 megawatts (MW) were forced off the grid. The state and electricity providers alike called for Texans to reduce their consumption as much as possible to ease the bridge burden.
Those rotating outages turned into controlled outages during the late morning.
ERCOT President Bill Madness said in the release, “Every grid operator and every electric company is fighting to restore power right now.”
Most of Texas is powered by its own grid, unlike much of the rest of the continental U.S. which uses power grids that span state lines.
This relative autonomy gives Texas some degree of added security, especially being the energy hub it is. But strenuous circumstances, such as a snowstorm in a place not used to such conditions, can stretch that security to its limits.
Texas’ grid is also markets based, rather than contract-based — meaning, prices are paid after consumption, not negotiated beforehand. The grid is also powered by a diverse set of sources.
Nearly half of Texas’ electricity is generated by natural gas, while coal and wind provide about 20 percent each. Nuclear amounts to nearly 11 percent while solar, hydro, and biomass produce the rest.
During normal times, Texas’ grid operates between 60,000 and 70,000 MW. One megawatt is enough to power roughly 650 homes. It can generate more but some capacity is kept in reserve.
The grid’s capacity is momentary. Electricity, once generated, cannot be set aside for later in any meaningful quantity. It’s either on the grid or it’s not. Calls to reduce consumption are meant to help lighten the grid’s load in that instant.
As of early afternoon on Monday, the current grid capacity — meaning, the total amount of electricity that can be generated in a given moment — is just shy of 51,000 MW. And the current grid demand, or usage total, is about 4,000 MW less than capacity.
That’s not a huge cushion.
Last summer, a heatwave caused a projected record-high consumption above 75,000 MW. To prepare for that, ERCOT set its reserve margin to 12.8 percent — or about 9,000 MW.
This time around, ERCOT says over 40 percent of the lost generation stemmed from inoperable wind turbines in West Texas that froze over.
Despite that, an ERCOT spokesman stated wind generation was outperforming their winter expectations. The rest, ERCOT added, came from coal, natural gas, or nuclear facilities that either shut down or failed to generate enough to keep up with demand.
Blackouts throughout the state vary in length, but hours-long outages are frequent. Wholesale electricity prices are floating between $2,500 and $2,800 per MW depending on the region of the state.
Dan Woodfin, ERCOT spokesman, said, “This event was well beyond the designed parameters for a typical or even extreme Texas winter that you would plan for.”
An estimated 2 million people were without power at points on Monday.