CHEYENNE, Wyo. (AP) — Wyoming generally favors low taxes and coal-fired electricity but its highest court says a utility must pay sales tax on pollution-control chemicals at power plants.

The Wyoming Supreme Court sided with the state Board of Equalization and ruled unanimously Thursday against Portland, Oregon-based PacifiCorp.

PacifiCorp uses chemicals to remove sulfur dioxide from flue gas at four coal-fired power plants in Wyoming. Other chemicals purify water within the plants' boiler tubes.

PacifiCorp argued the utility shouldn't have to pay sales tax on the chemicals. Wyoming law exempts sales tax on ingredients used in manufacturing products and PacifiCorp argued it manufactures electricity.

The high court ruled the chemicals aren't ingredients necessary to make electricity. PacifiCorp officials say they've been paying the sales tax and the ruling won't affect generation costs.