Avista Corporation, together with its subsidiaries, operates as an electric and natural gas utility company. It operates in two segments, Avista Utilities and AEL&P. The Avista Utilities segment provides electric distribution and transmission, and natural gas distribution services in parts of eastern Washington and northern Idaho; and natural gas distribution services in parts of northeastern and southwestern Oregon, as well as generates electricity in Washington, Idaho, Oregon, and Montana. This segment also engages in the supply of electricity to customers in Montana; and wholesale purchase and sale of electricity and natural gas. The AEL&P segment offers electric services in Juneau, Alaska. The company generates electricity through hydroelectric, thermal, wind, and solar generation facilities. As of December 31, 2023, it supplied retail electric services to approximately 416,000 customers; and retail natural gas services to approximately 381,000 customers. The company also operates five hydroelectric generation facilities with capacity of 102.7 MW; and four diesel generating facilities with a capacity of 107.5 MW. It also engages in venture fund investments, real estate investments, and other investments. Avista Corporation was incorporated in 1889 and is headquartered in Spokane, Washington.