Rate and Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2023

Regulated Operations [Abstract]

Schedule of Solar Projects

The following table provides information with respect to each agreement:

	Boomtown Solar Project(a)(b)	Huck Finn Solar Project(b)(c)	Split Rail Solar Project(d)	Cass County Solar Project(d)	Vandalia Solar Project(d)	Bowling Green Solar Project(d)
Agreement type	Build-transfer	Build-transfer	Build-transfer(e)	Development-transfer(e)(f)	Self-build(e)(g)	Self-build(e)(g)
Facility size	150-MW	200-MW	300-MW	150-MW	50-MW	50-MW
Status of MoPSC CCN	Approved April 2023	Approved February 2023	Filed June 2023(h)	Filed June 2023(h)	Filed June 2023(h)	Filed June 2023(h)
Status of FERC approval of acquisition	Received October 2023	Received March 2023	Expect to request by mid-2024	Not applicable	Not applicable	Not applicable
Earliest completion date(i)	Fourth quarter 2024	Fourth quarter 2024	Mid-2026	Fourth quarter 2024	Fourth quarter 2025	First quarter 2026

(a)The Boomtown Solar Project is expected to support Ameren Missouri’s transition to renewable energy generation and serve customers under the Renewable Solutions Program discussed below.

(b)These projects collectively represent approximately $0.65 billion of expected capital expenditures.

(c)The Huck Finn Solar Project is expected to support Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard. Investments in the project will be eligible for recovery under the RESRAM.

(d)These solar projects are expected to support Ameren Missouri’s transition to renewable energy generation.

(e)These projects, and applicable agreements, are subject to the issuance of a CCN by the MoPSC.

(f)Ameren Missouri entered into an agreement to acquire the Cass County Solar Project, which includes project design, land rights, and engineering, procurement, and construction agreements for a solar generation facility. Ameren Missouri will construct the facility after obtaining a CCN from the MoPSC and acquiring the project. Acquisition of the project is expected by mid-2024.

(g)Ameren Missouri entered into engineering, procurement, and construction agreements to construct these solar projects.

(h)In October 2023, the MoPSC staff filed a recommendation that the MoPSC should not approve Ameren Missouri’s requests for CCNs for these solar projects, arguing Ameren Missouri did not adequately demonstrate the facilities are needed to continue providing service to customers. Ameren Missouri expects decisions on the CCNs by the MoPSC in the first quarter of 2024.

(i)Expected completion dates are dependent on the timing of regulatory approvals, among other things.

Schedule of MYRP details

The following table includes the forecasted revenue requirement, the ROE, the capital structure common equity percentage, and the forecasted average annual rate base for 2024 through 2027, as reflected in Ameren Illinois’ revised MYRP filing, the ICC staff’s filing, and the administrative law judges’ proposed order:

	Ameren Illinois’ September 2023 Filing:				ICC Staff’s September 2023 Filing:				Administrative Law Judges’ October 2023 Proposed Order:
Year	2024	2025	2026	2027	2024	2025	2026	2027	2024	2025	2026	2027
Forecasted Revenue Requirement (in millions)(a)	$1,289	$1,385	$1,480	$1,556	$1,211	$1,295	$1,383	$1,435	$1,219	$1,306	$1,389	$1,450
ROE(b)(c)	10.5%	10.5%	10.5%	10.5%	8.9%	8.9%	8.9%	8.9%	9.24%	9.24%	9.24%	9.24%
Capital Structure Common Equity Percentage(c)(d)	53.99%	53.97%	54.02%	54.03%	50%	50%	50%	50%	50%	50%	50%	50%
Forecasted Average Annual Rate Base (in billions)	$4.3	$4.6	$4.9	$5.2	$4.1	$4.4	$4.6	$4.8	$4.1	$4.4	$4.6	$4.8

(a)If an initial rate increase phase-in provision, discussed below, is approved by the ICC, it would not affect the annual revenue requirement, but would affect the timing of associated recovery from customers.

(b)The ICC staff filing recommended an ROE based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points, to be updated annually for each applicable calendar year of the MYRP. An estimated ROE of 8.9% was used to calculate the forecasted revenue requirements in the ICC staff filing, which is based on the average monthly yields of the 30-year United States Treasury bonds for 2022. The ICC staff proposed that variances in the revenue requirement resulting from a change in the ROE would be excluded from the reconciliation cap discussed below.

(c)In November 2023, Ameren Illinois updated its requested ROE and capital structure common equity percentage to 9.85% and 52% for all years, respectively.

(d)A capital structure of up to and including 50% common equity is deemed prudent and reasonable by law. A higher equity ratio requires specific ICC approval. The administrative law judges’ October 2023 proposed order recommends a capital structure that is the lower of 50% or Ameren Illinois’ actual equity ratio, excluding goodwill.