Presque Isle’s fate has been up in the air since the plant that burns about 1.4 million tons of Powder River Basin coal annually lost 85% of its electricity sales in 2013 when Cliffs Natural Resources, a major mining company, switched its two iron ore mines in the UP to an alternative power supplier, Integrys Energy Services.

We Energies then proposed shutting Presque Isle in early 2014. But the Midcontinent Independent System Operator, a Pennsylvania-based power grid operator, stepped in, saying the baseload plant in Marquette on Lake Superior was needed to provide system reliability in the sparsely populated region.

UPPCO is a subsidiary of Chicago-based Integrys Energy Group, also the parent company of Integrys Energy Services. Wisconsin Energy is in the process of acquiring Integrys in a $9.1 billion transaction expected to close later this year.

If UPPCO buys Presque Isle, Cliffs has agreed in principle to purchase a significant portion of the power required by its iron ore mines from the plant until 2020. That is when Presque Isle is expected to close due to new federal air emission requirements affecting coal-burning generators.

As another part of the deal, Invenergy LLC, also based in Chicago, would construct a 280-megawatt natural gas-burning plant at one of Cliffs mines in the UP by 2020 and then begin supplying the mines.

The agreements are not yet final, but are expected to be worked out later this year.