In a shift away from nonrenewable energy sources, a coal-fired power plant that has been in operation on Navajo Nation land for nearly 50 years has shut down.

The Navajo Generating Station, which sits near the Arizona-Utah border, ceased operations on Monday (November 18). According to The Associated Press:

The 2,250-megawatt, three-unit plant was one of the largest in the U.S. West and had long been a target of environmentalists, who argued it polluted the air and contributed to health problems. Cheaper prices for power produced by natural gas, rather than environmental regulations, led the owners to decide in 2017 to close it.

It is expected that in three years time, the land now occupied by the plant will be fully restored to its original condition, reports The AP. There have been preliminary discussions to reseed it and grow plants that can be used to dye wool and make tea and traditional medicines.

“We need to heal from the wrongs of the past by returning to Diné traditional law, and prioritizing energy and water management policies that are in line with our values and virtues as stewards of the natural world,” environmentalist Marie Gladue of the Black Mesa Water Coalition told The AP in an interview.

Arizona utility Salt River Project (SRP), which operated the plant, purchased two solar and battery storage plants last week, making it one of the largest investors in energy storage in the country.

The plant was reportedly a major revenue source for the Navajo and Hopi tribes. Its workforce was an estimated 90 percent Navajo. Leaders from the Navajo Nation are considering turning a railway station that transported coal to the plant into a tourism site that can be used to generate revenue.

The closure of the plant is in line with trends happening within the coal industry. The U.S. Energy Information Administration found that between 2010 and the first quarter of 2019, U.S. power companies announced the shutdown of more than 546 coal-fired power units.