Dive Brief:

• The Houston Chronicle reports that NRG Energy and Calpine have filed a lawsuit against Texas regulators in a Travis County district court challenging a major transmission project as expensive and unnecessary.
• The generators say the Houston Import Project, approved by the Texas Public Utilities Commission and endorsed by ERCOT last year, is not needed to enhance reliability, as regulators claim. The filing is an appeal a unanimous PUC decision last year that rejected the generators' claims.
• NRG and Calpine allege that regulators and ERCOT are using faulty methods for assessing reliability. The commission had no response to the lawsuit, and is represented by the state's attorney general.

Dive Insight:

NRG and Calpine continue to battle the $590 million transmission project, arguing that backers have not shown sufficient need for the new investment. 

The project, scheduled to be completed by 2018, is a 130-mile, 345-kilovolt double line from the Limestone substation in ERCOT's North zone to the Gibbons Creek substation in Grimes County, and then to the Zenith substation northwest of Houston. The project will also inclide upgrades to the Limestone, Gibbons Creek, and Zenith substations and improvements to the existing T.H. Wharton-Addicks 345-kilovolt line.

Supporters of the Houston Import Project say it is necessary to maintain reliability. But the generators maintain the line's need has not been properly assessed, and that ERCOT is looking at grid reliability in the wrong way. NRG and Calpine believe ERCOT's assumption that building the line will result in more resource generation in the rest of the state lacks support.

“We remain convinced that the (project) is not needed at this time and would be costly for electric consumers,” Calpine spokesman Brettt Kerr said in a statement, according to the Chronicle.