Cross Texas Transmission (CTT) and Garland Power & Light (GP&L)
CTT is a transmission service provider that operates and maintains more than 320 kilometres of high-voltage transmission lines that deliver wind resources generated in the Texas Panhandle to the rest of Texas. GP&L is the municipal utility for the City of Garland, providing power and transmission services.
Houston and the surrounding metropolitan area is one of the largest load centres in the Electric Reliability Council of Texas (ERCOT) system. To meet demand, it relies on electricity generated in Houston and, during peak load conditions, power imports from the rest of the ERCOT system. Load growth, coupled with generation retirement, was causing a need to increase import capacity by 2018. Cross Texas Transmission (CTT) and Garland Power & Light (GP&L) recognized the issue and decided they could provide a solution.
DNV GL was selected by CTT and GP&L to carry out an independent reliability analysis to identify and test transmission system alternatives that would mitigate Houston’s future reliability concerns. DNV GL winnowed thirty potential solutions down to the ten that optimally addressed the need for increased reliability. These underwent a detailed load deliverability analysis for future-year cases, performed from a thermal and voltage stability basis. We recommended three preferred solutions, including a 190-kilometres, 345 kV double circuit line from Limestone to Gibbons Creek to Zenith, as well as technical support for the analysis.
ERCOT selected the plan DNV GL formulated for CTT and GP&L: the double circuit line from Limestone to Gibbons Creek to Zenith based on their independent assessment.