PHOENIX (AP) – Navajo Nation officials and a power utility that is the Navajo Generating Station's managing owner are expressing optimism about reaching an agreement soon to keep the coal-fired plant operating through 2019.

The Salt River Project and the tribe said in a joint statement released late Monday they have made "considerable progress" in negotiations toward agreement on a replacement lease, which would preserve jobs and revenue for the Navajo Nation and the Hopi Tribe for at least two more years.

The plant's owners cited the availability of less expensive power generated by burning natural gas when they announced in February they plan to close it in December 2019 when their lease expires.

SRP, which operates the plant at Page in northern Arizona on behalf of itself and other owners, has said decommissioning the plant by the end of 2019 under the current lease would require shutting down the plant this year so it could be removed and its site restored before the end of the lease.

A replacement lease to continue operations through 2019 could delay the start of the decommissioning process or allow the Navajo Nation or others to acquire the plant and keep it in operation.

"While there are a number of details that require additional discussions, both the Navajo Nation and the NGS owners are optimistic that a successful conclusion can be reached soon. If a draft agreement can be reached soon, it will provide time for required approval from the Navajo Nation Council and the NGS owners," the joint statement said.

The current owners require a final decision by July 1, the statement said.

SRP is negotiating on behalf of the plant's owners, which also include the U.S. Bureau of Reclamation, Arizona Public Service Co., Tucson Election Power Co. and NV Energy.