By Tom Kleckner

Electric Transmission Texas told ERCOT market participants last week that it is working closely with the ISO to minimize the economic effects of an 18-month project to repair cracks on metal transmission structures that will result in extended transmission outages through November 2018.

ETT, a joint venture between subsidiaries of American Electric Power and Berkshire Hathaway Energy, is currently inspecting transmission facilities on seven different 345-kV lines in Northwest Texas. The lines were all built as part of the Competitive Renewable Energy Zones (CREZ) project, which resulted in 3,600 miles of transmission to carry West Texas and Panhandle wind energy east to urban load centers. The project was completed in 2013 at a cost of $6.9 billion.

The transmission company notified market participants in May that it would be taking the CREZ lines out of service to inspect and, if necessary, replace structural components as part of a warranty claim. ETT said the work would involve visual and ultrasonic inspection of 2,743 structures, 21,944 arms, and 2,192 flanges and baseplates.

“Our contractors and suppliers are committed to completing things and not just doing the work to go home,” ETT President Kip Fox told market participants during a June 15 web conference. “We’re very confident we’re pursuing a solution that limits our costs to ratepayers, supports long-term reliability, improves safety and reduces the risk of unplanned outages.”

Fox and ERCOT staff both answered questions from market participants, many of them wind farm owners and developers.

In response to a written question about whether wind farms would be taken offline by the maintenance work, staff said its “current understanding” of the outage does not indicate that any generation resources will be “islanded” from ERCOT’s grid. The ISO expects some market participants will encounter congestion caused by the work, but it has not performed any specific resource analysis.

The Texas grid operator said it will schedule a second web conference to discuss an alternative ordering of the outages and address concerns about their effects on production costs.

Fox said ETT decided to address the structural issues now, “rather than the next 70-some-odd years.”

The company said it first discovered cracking on a structure arm in late 2012 and began a full inspection and arm replacement of more than 2,000 tangent poles in July 2016. The transmission structures are all steel, single-pole, 345-kV, double-circuit towers. Cracked arms and arm brackets will be replaced, and cracked baseplates and flanges will be repaired.

Inspection, repair and replacement crews are working in tandem, and line clearances will be taken continuously to help speed the work along. Outages will be scheduled one at a time and coordinated with ERCOT to minimize effects on the system.

A detailed work schedule and specifics on the outages’ timing and duration can be found in ERCOT’s outage scheduler.