Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Schedule of Lease Costs

The following table provides information related to our lease costs (dollars in thousands):

	Year Ended December 31,
	2023		2022		2021
Operating Lease Cost - Purchased Power & Energy Storage Lease Contracts	$	126,655	$	104,001	$	105,762
Operating Lease Cost - Land, Property, and Other Equipment	19,235		18,061		18,498
Total Operating Lease Cost	145,890		122,062		124,260
Variable Lease Cost (a)	135,007		122,040		118,969
Short-term Lease Cost	21,530		9,928		3,872
Total Lease Cost	$	302,427	$	254,030	$	247,101

(a)     Primarily relates to purchased power lease contracts.

The following tables provide other additional information related to operating lease liabilities (dollars in thousands):

	Year Ended December 31,
	2023			2022		2021
Cash paid for amounts included in the measurement of lease liabilities — operating cash flows:	$	123,472		$	118,463	$	116,661
Right-of-use operating lease assets obtained in exchange for operating lease liabilities	602,301		(a)	16,990		500,582

	December 31, 2023		December 31, 2022
Weighted average remaining lease term	10 years		7 years
Weighted average discount rate (b)	4.53	%	2.21	%

(a)Primarily relates to the two purchased power operating lease agreements that were modified in January 2023.

(b)Most of our lease agreements do not contain an implicit rate that is readily determinable. For these agreements we use our incremental borrowing rate to measure the present value of lease liabilities. We determine our incremental borrowing rate at lease commencement based on the rate of interest that we would have to pay to borrow, on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. We use the implicit rate when it is readily determinable.

Schedule of Maturities of Operating Lease Labilities

The following table provides information related to the maturity of our operating lease liabilities (dollars in thousands):

	December 31, 2023
Year	Purchased Power & Energy Storage Lease Contracts		Land, Property & Equipment Leases		Total
2024	$	108,201	$	14,750	$	122,951
2025	124,968		12,148		137,116
2026	138,692		9,826		148,518
2027	164,613		7,731		172,344
2028	168,410		5,401		173,811
Thereafter	835,813		64,090		899,903
Total lease commitments	1,540,697		113,946		1,654,643
Less imputed interest	334,693		41,878		376,571
Total lease liabilities	$	1,206,004	$	72,068	$	1,278,072