A Northern New Mexico electric cooperative is preparing to file a formal protest against a rate increase that a Colorado generator plans to pass along to 44 rural co-ops in four states starting Jan. 1.

A spokesman for Kit Carson Electric Co-op, which serves 29,500 members in Taos, Colfax and Rio Arriba counties, said Monday that a protest letter will be submitted to the New Mexico Public Regulation Commission over last month's decision by Tri-State Generation and Transmission Association Inc. to raise the rates it charges for electricity by an average of 4.5 percent.

Tri-State's board approved the proposal by a 43-to-1 vote in September, with Kit Carson's representative casting the lone no vote. Kit Carson's executive director, Luis Reyes, noted Monday that the rate hike would be Tri-State's seventh in 11 years.

To trigger a review of Tri-State's rate hike by the Public Regulation Commission, Reyes said, two more co-ops must file formal protests.

"It's an individual co-op's decision," Reyes said. "It's up to their collective boards. We've talked to co-ops, but we haven't put a lot of pressure."

A Tri-State spokesman said the rate hike would be the company's first in three years and would cost the average consumer $3.18 a month.

Growth in the customer base of member co-ops was one factor that led to the decision, Lee Boughey said. The 44 co-ops Tri-State sells to serve 1.5 million people in New Mexico, Colorado, Nebraska and Wyoming.

A rate increase also helps the company borrow money at favorable rates for plants and other infrastructure needs, Boughey said, adding that a strong bond rating means lower debt costs, which "saves consumers hundreds of millions of dollars."

Reyes said he believes Tri-State wants to bolster its bond rating because it is anticipating a loan for a new plant in Holcomb, Kan.

If the rate increase goes into effect Jan. 1, Reyes said, his co-op will pass the cost along to its customers.

Contact Trip Jennings at 986-3050 or at tjennings@sfnewmexican.com.