(AP) — The largest coal-fired power plant in the West will produce one-third less energy by 2020 and is on track to cease operations in 2044 under a proposal that the federal government adopted to cut haze-causing emissions of nitrogen oxide at places like the Grand Canyon. Along with meeting energy demands in the West, the 2,250-megawatt plant powers a series of canals that deliver water to Phoenix and Tucson, fuels the economies of the Navajo and Hopi Tribes, and helps fulfill American Indian water-rights settlements with the federal government. A group made up of the plant's operator, tribal and federal officials, a canal system known as the Central Arizona Project and environmental groups said they could do better and came up with their own proposal, which was adopted by the EPA. "[...] while we're increasing our costs associated with the plant, the plant itself is still valuable enough to our customers and Arizona for us to continue," Salt River Project spokesman Scott Harelson said. Steve Michel of the environmental group Western Resource Advocates said he would have liked to see faster action to improve air quality.