Tucson Electric Power Co. disclosed Dec. 9 that it will exercise its option to purchase an additional interest in the Springerville coal-fired power plant in Apache County, Ariz.

Tucson Electric leases a part of the facility under two separate agreements that expire in January 2021, according to a filing.

The Fortis Inc. subsidiary will acquire the stake for $68 million upon expiration of the leases, instead of renewing, and record the $67 million present value of the purchase price on its balance sheet.

The utility said it also notified unit 3 lessee Tri-State Generation and Transmission Association Inc. and unit 4 owner Salt River Project Agricultural Improvement & Power District of its plans to exercise its purchase options under those contracts.

Once Tucson purchases 100% of the Springerville common facilities, according to the filing, Salt River Project will be obligated to buy a 14% undivided interest in the facilities for approximately $30 million, and Tri-State will either have to buy a 14% undivided interest in the facilities at the same price, or continue to pay Tucson Electric for using the facilities.