Entergy Texas proposes new 230 kV transmission line

Entergy unit Entergy Texas is proposing to design and build a new, predominantly single circuit, 230-kV transmission line in Jefferson, Chambers and potentially Liberty counties in Texas.

The new line would connect the existing China substation located just west of China, Texas, in Jefferson County, to the existing Stowell substation located in the unincorporated community of Stowell, Texas, in Chambers County. Entergy Texas also said that it would install new equipment at both substations.

The new line is proposed to alleviate power flow limitations in the southern portion of Entergy Texas’ service territory, the company said, noting that in addition to the line, the Stowell substation would be expanded to accommodate the new line bay and a new 230/138-kV 400 MVA autotransformer. Additionally, a new line bay would be added within the existing footprint of the China substation for the new 230-kV line.

Further discussing the project’s need, Entergy Texas said the project would mitigate line overloads and alleviate low-voltage criteria that violate both NERC Planning Standard (TPL-001-4) and Entergy’s transmission planning criteria. Entergy Texas said that it and the Midcontinent ISO (MISO) have determined that the line would be necessary before the summer of 2019 in order to provide adequate and reliable service to customers in the southern portion of the company’s service area.

Entergy Texas said that the line would be about 20.6 miles to 26.7 miles long, depending on the final route approved by the PUC.

The company said that steel/concrete monopole structures were selected for the project due to their relatively small footprint compared to H-frame structures (two poles) or four leg steel lattice towers. Furthermore, those structures are easier to engineer and are aesthetically more appealing to property owners than the other two alternatives, the company said.

Entergy Texas also noted that most of the study area is a rural setting with the exception of urban areas associated with, for instance, China and Stowell. Most of the study area is predominantly agricultural, the company said, adding that many habitable structures in the rural portions of the study area are associated with rural ranch or “ranchette” properties.

Most of the study area has been impacted by land improvements associated with agriculture, residential structures, roadways and various utility corridors.

The estimated schedule calls for right of way (ROW) and land acquisition to begin in August 2017, and be completed in August 2018, while engineering and design is set to begin in August 2017, and be completed in March 2018. Material and equipment procurement is set to begin in August 2017, and be completed in May 2018, while construction of the facilities is set to begin in March 2018, and be completed in May 2019. The facilities are set to be energized in June 2019, the company added.

Entergy Texas said that it plans to finance the construction through borrowings and equity, either through withholding dividends and/or contributions from the company’s parent, Entergy.

Entergy Texas said that it retained POWER Engineers to prepare the environmental assessment and alternative route analysis for the proposed project. The company said that 17 primary alternative routes were eventually identified for comparative purposes.

The company said that it used a consensus process to independently select “Route 7″ as the primary alternative route that Entergy Texas representatives believe best addresses certain requirements. Route 7 is the most prudent avoidant based on estimated cost and number of habitable structures within 300 feet, and it is POWER’s third-ranked route, ranking well from an environmental and land use perspective, the company said.

Route 7 has the lowest estimated cost at about $68.5m; is tied with “Route 6″ with having the least number of habitable structures within 300 feet (three); is tied with other routes for the fewest number of additional parks/recreational areas within 1,000 feet (zero); and has the second-shortest length across pasture/rangeland (7.21 miles).

Among other things, the company further noted that Route 7 is not within 1,000 feet of any known cemeteries; crosses no known/occupied habitat of federally endangered or threatened species; does not parallel adjacent to (within 100 feet) of any natural streams or rivers; and does not cross, or is within 1,000 feet of, any recorded historic or prehistoric sites, including any sites listed or eligible for listing on the National Register of Historic Places.

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Corina Rivera-Linares, chief analyst for TransmissionHub, has covered the U.S. power industry for the past 10 years. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial. She has also covered such topics as health, politics and education for weekly newspapers and national magazines. She can be reached at corinar@pennwell.com .

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