Utility regulators in Louisiana on Wednesday approved American Electric Power’s (AEP) controversial $4.5bn Wind Catcher Energy Connection, providing much-needed momentum for the largest single-site wind project in the Americas.

Louisiana is the second state to preapprove cost recovery after regulators in neighboring Arkansas last month greenlighted the proposed 800-turbine, 2GW wind farm.

The Texas Public Utility Commission has scheduled a meeting with its three commissioners on 12 July to review the project after prior hearings were held.

That leaves Oklahoma, where Wind Catcher faces opposition from state Attorney General Mike Hunter, the Public Utility Division of the Oklahoma Corporation Commission (OCC), which regulates electric utility service, and several communities.

Opponents there allege AEP is overstating economic benefits from a project that they believe is too risky for ratepayers.

The Commission has not said when it will rule on the issue although AEP expects a decision later this month or during the first half of July.

AEP-PSO is asking for preapproval of the costs of the project and a waiver of the law that requires competitive bidding for preapproved costs.

Wind Catcher would be built in Oklahoma’s geographically remote western Panhandle region. GE would supply the turbines, its largest contract since it entered the wind business in 2002.

A new dedicated 360-mile (580km) overhead transmission line would bring the electricity east to customers served by AEP subsidiaries Public Service Company of Oklahoma (PSO) and Southwestern Electric Power Company (SWEPCO).

SWEPCO serves regions of Arkansas, Louisiana and Texas. The utility anticipates Wind Catcher will save its customers more than $4bn over the 25-year life of the wind farm, compared to projected costs of buying power on the open market.

“Wind Catcher is a major investment in clean energy that will produce long-term savings for Louisiana customers and further diversify our energy resource mix,” Nick Akins, chief executive of AEP, said in a statement.

Cost savings would include no fuel expense for wind, which lowers SWEPCO’s overall fuel and purchased power costs; full value of the federal production tax credit, and the cost-efficient delivery of the wind generation to customers through the new, dedicated power line.

Those 231,000 customers will see savings primarily through a reduction in the fuel portion of their bills, beginning in 2021, according to AEP.

Key elements of the settlement agreement approved by the Louisiana Public Service Commission are guarantees agreed to by SWEPCO, including a cap on construction costs, qualification for 100% value of PTCs and minimum annual production from the project.

Wind Catcher is under development by Chicago-based Invenergy. SWEPCO and PSO will purchase the facility at completion, which is scheduled for the fourth quarter of 2020.

Clarifies role of Oklahoma Corporation Commission and what AEP-PSO has requested for the project