Xcel Energy has filed a federal lawsuit seeking reconsideration of an emissions rule that could lost customers and additional $8 a month on their electricity bills.

The bill is known as the Cross-State Air Pollution Rule and is supposed to cut down on smog-producing emissions that drift across state lines.

Along with Xcel Energy, Southwestern Public Service (SPS) filed the lawsuit. The rule mandates that SPS recude certain power plant emissions by 50 percent by January 2012.

SPS and Xcel said they were not aware Texas was included in the rule and they don't have time to make the switch.

"The imposition of CSAPR's new requirements on such an unreasonable schedule provides SPS with insufficient time to retrofit our generating units with the emissions-control technologies we already were planning to install over the next several years," said Riley Hill, president and CEO of SPS. "A few months is not enough time to accomplish this.