Tri-State is also feeling some pressure from state regulators. In January, the Colorado Public Utilities Commission launched an investigation to determine whether to assert state authority over the wholesaler's energy resource planning. The PUC said that public concerns about climate change, uncertainty about future costs of generating power, and state mandates for more renewable energy spurred it to take a closer look at Tri-State's energy mix. The PUC will meet in mid-July with representatives of the company, member co-ops and environmentalist and consumer groups before reaching a final decision.

In response to the recent scrutiny, Tri-State began airing TV ads boasting of its push toward energy efficiency, conservation and renewable energy. In April -- after Kansas' then governor, Kathleen Sebelius, vetoed bills that would have allowed Tri-State and Sunflower Electric to build the two Holcomb coal plants -- Tri-State announced that it was re-evaluating its long-term resource plans. The company pledged to rely more on wind and solar and to depend less on conventional coal plants.

Environmental organizations lauded the new approach, which includes plans for a 30-megawatt solar photovoltaic plant in northeastern New Mexico and a wind project in Colorado. But their enthusiasm has since waned. In May, Kansas' new governor, Mark Parkinson, OK'd the construction of one 895-megawatt coal plant in Holcomb near the Colorado border, provided that it develops some wind energy on the side. Tri-State has invested roughly $60 million in the $3.8 billion project and plans to rely on the new plant for some of the 300 to 700 megawatts of increased capacity that it expects it will need over the next decade.

"With the Kansas plant back in play, there's a concern that Tri-State will fall back into its traditional way of doing business," says John Nielsen, energy project director at Western Resource Advocates in Boulder, Colo. 

Meanwhile, some of Tri-State's member co-ops continue their incremental push toward carbon-cutting goals. In fact, some have more ambitious goals than those mandated by the states. Kit Carson, for example, which serves many affluent and liberal Taos residents, aims to generate 15 percent of its energy mix from its own renewable projects by 2020, says Reyes, a more aggressive goal than New Mexico's mandate for rural electric co-ops. But it would be easier and more economically attractive to set and reach such goals if Tri-State allowed Kit Carson and other member co-ops to sell their locally generated power at market prices, he adds, not just the price set by Tri-State. Kit Carson, which is working on a relatively large photovoltaic array for the University of New Mexico and has installed photovoltaic panels on homes, schools and other buildings, still has a long way to go: The co-op currently controls and generates less than 1 percent of its power from local sources, although nearly 5 percent of the power it buys from Tri-State is from renewable resources.

Highline Electric Association in the northeastern Colorado city of Holyoke now meets 5 percent of its electricity needs with a 3.5-megawatt gas compression station that turns waste heat from natural gas turbines into electricity -- a process that qualifies under Colorado's renewable portfolio standards. Highline, like several other co-ops whose service territory depends heavily on agriculture, is trying to garner state grants for other renewable energy projects, such as small-scale hydroelectricity and community-scale wind farms.

Delta-Montrose, meanwhile, still generates less than 1 percent of its electricity from local and renewable sources, though it is a leader in energy efficiency and conservation. The co-op's greatest success so far has been in selling and installing about 600 ground-source heat pumps, or geothermal pumps, which offset the need for using natural gas and electricity to heat and cool homes and businesses. Delta-Montrose is also seeking funding for a 5-megawatt hydroelectric dam, as well as a project that would capture methane -- a greenhouse gas 21 times more potent than CO2 -- from nearby coal mines and convert it to natural gas-based electricity. 

Despite these steps toward greener power, don't expect Delta-Montrose leaders to trash-talk coal; after all, the three local coal mines are the co-op's biggest electricity consumers, as well as the biggest and among the highest-paying employers in the relatively low-income region. And coal's going to be a big part of the energy mix for a long time. "It takes a while to change culture and contracts," says Dan McClendon, Delta-Montrose's general manager. "There's a lot of 'new energy economy' jargon, but it just doesn't happen overnight."