Tri-State Generation and Transmission Association Inc. expects it will have to develop less renewable energy than expected on its own over the next several years because its members are developing their own projects, managers said Monday.

The electric cooperative, based in Westminster, Colo., provides power to 44 members who serve about 1.5 million people in Colorado, Wyoming, New Mexico and Nebraska.

Last fall, Tri-State submitted a 20-year plan to Colorado regulators outlining how it planned to meet demand for electricity over the next two decades while also satisfying mandates in Colorado and New Mexico to get more power from renewable sources. It plans to submit an update Nov. 30 after collecting public input.

Tri-State is studying potential renewable energy projects for the future. But at a public meeting Monday, managers said the cooperative's members have proposed their own wind, solar, small hydro- and waste recovery projects, along with one to recover methane from landfills.

"Our members have come to us at virtually every board meeting with renewable energy projects," said Robert Wolaver, senior manager for energy resources.

In 2010, Tri-State projected it would need the equivalent of about 150 megawatts of extra wind generation in 2015 beyond what it has now to meet Colorado and New Mexico renewable energy standards, but it now forecasts that will be closer to 50 megawatts.

However, Bruce Driver of the environmental law and policy group Western Resource Advocates expressed concern Monday that Tri-State hasn't given up plans for Sunflower Electric Power Corp. to build a coal-fired plant outside Holcomb, Kan., that could serve Tri-State customers. Kansas officials have granted a permit for the plant, but environmental groups are challenging that decision in court. Tri-State doesn't expect a resolution until at least 2013.

Tri-State officials said it would be premature to scrap the Holcomb project because they want to keep all options — from nuclear power to wind — open when it comes to securing power in the future.

Tri-State is among the largest electricity providers in Colorado, but the state has had limited oversight of electric cooperatives. The Colorado Public Utilities Commission in 2009 considered whether it should further regulate the cooperative and its plans for providing electricity because of concerns about emissions from coal-fired plants, state mandates for more renewable energy, and uncertainty about costs for developing electricity projects.

Tri-State questioned the commission's legal authority to oversee its plans, but in late 2009 it reached an agreement with Western Resource Advocates to voluntarily allow more public and state input into its planning.

The cooperative doesn't need state approval of the plan.

The update to be filed Nov. 30 will reflect lower natural-gas prices and higher coal prices than Tri-State forecast last year.

Managers also said Monday the Tri-State board is considering redesigning its rates, but no changes are expected for 2012.