Trying to reconnect
A mobile unit will take the place of a flooded substation that routed power to 5,700 customers
The final piece needed to restore power for thousands of Houstonians is sitting dead in 2 feet of water, a giant substation hidden by a dense forest in the outskirts of west Houston.
But in the wake of a hurricane that deluged Houston in 51 inches of water, CenterPoint Energy has engineered a fix: A temporary mobile substation, sitting nearby on the trailers of semi truck, will be a backup for months while the company rebuilds. The fix will bring power back to around 5,700 customers, many of whom have been in the dark for more than week. Without it, those thousands could have been facing months without power.
“They would be out until we got Memorial substation fixed or thought of something else,” said John Kellum, CenterPoint’s division vice president of high-voltage power delivery. “The mobile substation is the only option.”
CenterPoint estimates the temporary substation will be running by Wednesday, but there will be still more than 7,000 CenterPoint customers from Wharton to Kingwood without power, some of whom are in mandatory evacuation zones or whose electrical systems have been damaged.
But the restoration of Memorial will begin a monthslong process of repairs, rebuilding and learning for CenterPoint, which over the years has adapted its system to withstand hurricanes, storm surges and catastrophic flooding. The cost to reconstruct Memorial is unknown, but rebuilding a substation of that size, which serves 12,000 customers, could cost up to $15 million, CenterPoint said.
The temporary substation will eventually power about 9,600 customers for months while CenterPoint engineers a replacement designed to withstand the worst flooding Houston has ever seen.
Since the effects of Hurricane Harvey hit the Houston area a week ago, more than 850,000 CenterPoint customers have lost power. The outages peaked
on Aug. 28, when they knocked out electricity for 120,000 customers at once. But even as CenterPoint crews have grappled with unprecedented flooding, the outages were still a fraction of what the city saw during Hurricane Ike in 2008, when 2.1 million people lost power — nearly all of CenterPoint’s 2.2 million customers at the time.
After Harvey hit the Gulf Coast, hundreds of linemen from around the country converged on Houston to repair a submerged power grid, but most of CenterPoint’s 2.4 million customers still had power.
When water starting coursing through the Memorial substation grounds, CenterPoint decided to shut it down for safety and to prevent further damage to its equipment, including controls and cooling system. Some of Memorial’s power was rerouted to other substations, which could power only some of the customers connected to Memorial.
Only six of CenterPoint’s 230 distribution substations — which send power to homes — were flooded, but in most areas water receded and crews were able to make repairs. But not at Memorial, where floodwaters were 4 feet deep around the wires of the substation. A week later, the substation was still sitting in a lake, and a core of CenterPoint customers remained in the dark because of the flooding. Crews used drones and boats to survey the damage.
The Memorial substation is half a century old, and until Harvey, had been one of CenterPoint’s most resilient, Kellum said.
“Ike, Allison, the Memorial Day floods of ’15, the Tax Day flood of ’16 — this substation was high and dry,” he said.
Crews will work 16hour shifts until Memorial’s power is transferred to the mobile substation, Kellum said. Once the substation is running again, CenterPoint will study how to rebuild Memorial to withstand floods on a Harvey-scale — possibly by raising the equipment above the flood level.
Other changes to substations across city have paid off — after Hurricane Allison in 2001 CenterPoint built an 8-foot wall to protect a substation at the Medical Center. After Harvey, the wall kept a foot of water away from the equipment.