REGULATORY MATTERS: Regulatory Matters Level 3 (Tables)

12 Months Ended

Dec. 31, 2023

Regulatory Assets and Liabilities, Other Disclosure [Abstract]

Schedule of Regulatory Assets and Liabilities

The following table presents a summary of Idaho Power’s regulatory assets and liabilities (in thousands of dollars):


		As of December 31, 2023
	Remaining Amortization Period	Earning a Return(1)		Not Earning a Return		Total as of December 31,
Description						2023		2022
Regulatory Assets:
Income taxes(2)		$	—	$	774,672	$	774,672	$	739,689
Unfunded postretirement benefits(3)		—		87,318		87,318		70,254
Pension expense deferrals(4)		253,744		1,500		255,244		249,503
Energy efficiency program costs(5)		—		—		—		3,767
Power supply costs(6)	2024-2025	134,816		(19,291)		115,525		129,309
Fixed cost adjustment(6)	2024-2025	36,037		15,248		51,285		41,901
North Valmy plant settlements(6)	2024-2028	82,917		—		82,917		90,747
Jim Bridger plant settlement(6)	2024-2030	108,376		15,256		123,632		80,531
Wildfire Mitigation Plan deferral(6)		—		51,329		51,329		27,078
Asset retirement obligations(7)		—		35,270		35,270		28,780
Long-term service agreement	2024-2043	12,679		8,276		20,955		22,114
Other	2024-2056	2,330		52,573		54,903		18,288
Total		$	630,899	$	1,022,151	$	1,653,050	$	1,501,961
Regulatory Liabilities:
Income taxes(8)		$	—	$	108,641	$	108,641	$	94,946
Depreciation-related excess deferred income taxes(9)		147,950		—		147,950		158,634
Removal costs(7)		—		175,369		175,369		180,087
Investment tax credits		—		165,479		165,479		115,285
Deferred revenue-AFUDC(10)		177,884		50,787		228,671		207,528
Energy efficiency program costs(5)		1,507		—		1,507		154
Power supply costs(6)		1,240		—		1,240		—

Mark-to-market liabilities		—		88		88		59,544
Tax reform accrual for future amortization(11)		—		40,891		40,891		32,793
Other		8,383		4,334		12,717		11,630
Total		$	336,964	$	545,589	$	882,553	$	860,601

(1) Earning a return includes either interest or a return on the investment as a component of rate base at the allowed rate of return. The interest rate on deferral accounts is published annually by the IPUC and OPUC. The applicable rates for 2023 were 2% and 4.5%, respectively.

(2) Represents flow-through income tax accounting differences which have a corresponding deferred tax liability disclosed in Note 2 - "Income Taxes."

(3) Represents the unfunded obligation of Idaho Power’s pension and postretirement benefit plans, which are discussed in Note 11 - "Benefit Plans."

(4) Idaho Power records a regulatory asset for the difference between net periodic pension cost and pension cost considered for rate-making purposes relating to Idaho Power's defined benefit pension plan. In its Idaho jurisdiction, Idaho Power’s inclusion of pension costs for the establishment of retail rates is based upon contributions made to the pension plan. This regulatory asset account represents the difference between cumulative cash contributions and amounts collected in rates. Deferred costs are amortized into expense as the amounts are provided for in Idaho retail revenues.

(5) The energy efficiency asset and liability represent the separate Idaho and Oregon jurisdiction balances at December 31, 2022, and December 31, 2023, respectively. During 2023, the balances changed from an asset to a liability in the Idaho jurisdiction.

(6) This item is discussed in more detail in this Note 3 - "Regulatory Matters."

(7) Asset retirement obligations and removal costs are discussed in Note 13 - "Asset Retirement Obligations (ARO)."

(8) Represents the tax gross-up related to the depreciation-related excess deferred income taxes and investment tax credits included in this table and has a corresponding deferred tax asset disclosed in Note 2 - "Income Taxes."

(9) In 2017, income tax reform reduced deferred income tax assets and liabilities. For depreciation-related temporary differences under the normalized tax accounting method, the resulting excess deferred taxes will flow back to customers ratably over the remaining regulatory lives of Idaho Power's plant assets under the alternative method provided in the statute.

(10) Idaho Power is collecting revenue in the Idaho jurisdiction for AFUDC on HCC relicensing costs but is deferring revenue recognition of the amounts collected until the license is issued and the asset is placed in service under the new license.

(11) Represents amount accrued under the May 2018 Idaho tax reform settlement stipulation (described below) for the future amortization of existing or future unspecified regulatory deferrals that would otherwise be a future liability recoverable from Idaho customers.

Schedule of Power Cost Adjustment Changes

The table below summarizes the three most recent Idaho-jurisdiction PCA rate adjustments, which also include non-PCA-related rate adjustments as ordered by the IPUC:


Effective Date	$ Change (millions)		Notes
June 1, 2023	$	105.1	The $105.1 million increase in PCA rates reflects higher market energy and natural gas prices, combined with lower-than-expected low-cost hydropower generation and limited coal supply. The increased rate also reflects an expectation of continued elevated market energy prices and natural gas prices in the forecast period.
June 1, 2022	$	94.9	The increase in PCA rates reflected a forecasted reduction in low-cost hydroelectric generation as well as higher costs associated with market energy prices and natural gas prices. The rate also reflected $0.6 million of 2021 earnings shared with customers under the 2018 Settlement Stipulation described below.
June 1, 2021	$	39.1	The net increase in PCA rates reflected a forecasted reduction in low-cost hydroelectric generation as well as higher costs associated with forecasted PURPA power purchases. The net increase in PCA rates also reflected a smaller credit to customers through the true-up component.

Schedule of Fixed Cost Rate Adjustments

The following table summarizes FCA amounts approved for collection in the prior three FCA years:


FCA Year	Period Rates in Effect	Annual Amount (in millions)
2022	June 1, 2023-May 31, 2024	$25.1
2021	June 1, 2022-May 31, 2023	$35.2
2020	June 1, 2021-May 31, 2022	$38.3

Schedule of Open Access Transmission Rates

Idaho Power's OATT rates submitted to the FERC in Idaho Power's four most recent annual OATT Final Informational Filings were as follows:


Applicable Period	OATT Rate (per kW-year)
October 1, 2023 to September 30, 2024	$	30.74
October 1, 2022 to September 30, 2023	$	31.42
October 1, 2021 to September 30, 2022	$	31.19
October 1, 2020 to September 30, 2021	$	29.95