Public Utility Commission of Texas staff recommends that the commission approve Electric Transmission Texas’ (ETT) application to amend its certificate of convenience and necessity (CCN) in order to build a new double-circuit, 345-kV electric transmission line, according to John Poole, an engineering specialist with the commission’s Infrastructure and Reliability Division.
Poole also said in his July 23 direct testimony – which was filed with the commission and provides staff’s recommendation regarding the need for the project as well as route selection – that the proposed project is necessary for the service, accommodation, convenience, and safety of the public.
As noted in his testimony, the proposed line would be supported by monopole steel structures connecting the existing AEP Texas Inc., Stewart Road substation, located south of the City of Donna, east of Farm-to-Market (FM) Road 2557/Stewart Road, to an interconnection point along the existing AEP Texas North Edinburg to Sharyland Utilities, L.P., Palmito 345-kV transmission line in Hidalgo County, Texas.
ETT said in its application that the CCN is needed to address overloads and system undervoltages during facility outages in the western Lower Rio Grande Valley.
“The combination of one of the local plants, the combined cycle plant Frontera, exporting its entire capacity to Mexico and projected load growth in the area is creating reliability facility overloads and under voltages during transmission outages,” Poole added. “These conditions violate NERC and ERCOT reliability criteria and could result in considerable load losses.”
The ERCOT Board of Directors in June 2016 recommended the proposed project as part of the Hidalgo-Starr Transmission project, a Tier 1 reliability project, he said.
Based on the independent study carried out by ERCOT included in ETT’s application, it is evident that the project is needed to fulfill reliability requirements in the region, he said.
Poole said that he concludes that ETT’s application is adequate and that ETT’s proposed routes are adequate in number and geographic diversity.
Poole said that he concludes that “Route B3” is the best route when weighing certain factors. He also noted that ETT – which proposed 15 routes for the project in its application – believes that that route best addresses certain requirements.
According to the filing, ETT’s estimated cost of Route B3 is about $16.8m, which is the least costly of the 15 proposed routes. That route has one habitable structure within 500 feet of the centerline, as do most of the other proposed routes, Poole said.
Route B3 is the shortest, he said, adding that the route is ranked the least visible, according to the data provided by POWER Engineers. Route B3 has no length of right of way across wetlands, and no park or recreational areas are located within 1,000 feet of the centerline of any of the alternative routes.
Poole also said that he believes that Route B3 is one of the strongest routes from a historical values perspective as it does not cross nor come within 1,000 feet of any archaeological sites, and it has the second least length across areas of high probability for prehistoric archaeological sites.
He noted that all of the proposed alternative routes would result in a negative impact in aesthetic values, some routes more than others, depending on the visibility from homes and public roadways. Route B3 is the shortest route, which would help to mitigate those impacts, Poole said.
He also noted that the Texas Parks and Wildlife Department in April said that it selects Route B3 as the route having the least potential impact on environmental integrity. Poole said that he concludes that the route is acceptable from an environmental and land use perspective.
He recommended that the commission state in its order approving ETT’s application that ETT is to conduct surveys to identify pipelines that could be affected by the proposed line, if not already completed, and coordinate with pipeline owners in modeling and analyzing potential hazards because of alternating current interference affecting pipelines being paralleled.
The commission should also state in its order that in the event that ETT or its contractors encounter any archaeological artifacts or other cultural resources during project construction, work is to cease immediately in the vicinity of the resource, and the discovery is to be reported to the Texas Historical Commission.
Among other things, he also recommended that the commission state in its order that ETT is to cooperate with directly affected landowners to implement minor deviations in the approved route to minimize the impact of the line.