RELATED-PARTY TRANSACTIONS - Related Party Purchases (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Fuel	$ 28,590,348	$ 32,970,826
Related party
Related Party Transaction [Line Items]
Fuel	3,995,019	3,854,881
Related party | Fuel Service and Beneficial Use Agreement ("FBUA") | Northampton Fuel Supply Company, Inc.
Related Party Transaction [Line Items]
Fuel	3,139,414	3,121,423
Related party | Waste Coal Agreement (the “WCA”) | Coal Valley Sales, LLC
Related Party Transaction [Line Items]
Fuel	$ 855,605	$ 733,458