Two American Electric Power Co. Inc. utilities have in recent weeks issued solicitations for more than 7 GW of wind and solar resources which, along with planned retirements of existing coal and gas assets, will dramatically transform their generation fleets.

Southwestern Electric Power Co., or SWEPCO, in June issued a request for proposals for up to 3,000 MW of wind resources, up to 300 MW of solar resources and up to 250 MW of short-term accredited deliverable capacity. The company serves 543,000 customers in Arkansas, Louisiana and Texas. Proposals were due in August, with projects to be in service by Dec. 15, 2024, or Dec. 15, 2025.

Public Service Co. of Oklahoma, or PSO, followed with a draft request for proposals in September, asking for 2,600 MW of wind resources and 1,350 MW of solar resources. The company serves about 560,000 customers across Oklahoma. A final request for proposals, or RFP, is due to be issued in November, and any selected projects' in-service dates are the same as in the SWEPCO RFPs.

SWEPCO will require that solar resources be interconnected to its transmission system and located within its service territory. Wind resources are to be interconnected to the Southwest Power Pool grid and located in any of six states. PSO is requiring that all wind and solar resources be located in Oklahoma.

The additional resources would have to go through the SPP's generation interconnection process which, a spokesperson said, is one method the grid operator uses to determine whether there is sufficient transmission capacity to support them.

The RFPs are related to a broader effort by parent company AEP, announced in April, to add more than 16,500 MW of renewable resources to its regulated fleet by 2030. The two Great Plains utilities are already transforming their respective power generation portfolios, which are about the same size, away from reliance on fossil fuels.

At PSO, wind resources to date comprise 29% of its 5,781 MW of owned and contracted capacity, according to S&P Global Market Intelligence data. The company has one remaining operating coal-fired plant in its fleet, unit 3 at the Northeastern plant in Rogers County, Okla. The 460-MW unit has been running since 1979. Another coal-fired unit at the site has already been retired but a gas-fired unit from 1970 is still running. Two combined-cycle units, known as Northeastern CC, were added in 2001.

SWEPCO's portfolio totals 5,691 MW, according to Market Intelligence data, with about 10% made up by wind and the remainder split about evenly between coal and gas. SWEPCO has ownership interests in five coal-fired plants and retirement dates have already been set for three.

SWEPCO owns a roughly 40% interest in the 645-MW lignite coal-fired Dolet Hills plant in De Soto County, La. The plant, operated by Cleco Power LLC is set to be retired at the end of 2021. The 675-MW Pirkey plant in Harrison County, Texas, is also fueled by lignite coal. SWEPCO owns about an 86% interest and plans to retire the plant in 2023, to comply with the U.S. Environmental Protection Agency's Coal Combustion Residuals rule.

When SWEPCO disclosed its retirement plans for Pirkey in November 2020, the utility also said it would retire the 1,056-MW Welsh plant in Titus County, Texas, in 2028. One of the three units at Welsh was shut down in 2016.

The two companies made a splash into the wind sector in 2019 when they announced the planned acquisition of three wind farms in Oklahoma known collectively as the North Central Energy Facilities, with a combined output of 1,485 MW. Ownership is split 55% for SWEPCO and 45% for PSO. Independent power producer Invenergy LLC is developing the three projects and the AEP utilities are acquiring them upon completion. The first, the 199-MW Sundance Wind Project began operating in April and the second, the 287-MW Maverick Wind Project began operating in September. The third, the 999-MW Traverse Wind Energy Center, is due to begin operating in early 2022.

Texas regulators in July 2020 refused to allow SWEPCO to acquire its share of the North Central facilities, though regulators in Arkansas and Louisiana did. SWEPCO has allocated the output and related costs to its Arkansas and Louisiana customers, with a portion dedicated to wholesale customers.

Under the 2021 RFPs, the two AEP companies are looking to acquire the renewable energy facilities from their developers, which would require approval from both state regulators and the Federal Energy Regulatory Commission.

If the entire portfolio is not approved, "we may reduce the size of the portfolio accordingly by eliminating one or more projects from the portfolio," SWEPCO spokesperson Peter Main said. "We would proceed with the projects that meet the needs of the approving jurisdictions."