(a) The WEC obligation owed for each reporting year must be paid by the WEC obligated party as part of the annual WEC filing, as required by § 99.7(b), and is considered due at the date specified in § 99.5.

(b) Other than the WEC obligation specified in paragraph (a) of this section, all other charges required by this part, including adjusted WEC obligations, interest fees, and penalties, shall be paid by the WEC obligated party in response to an invoice or bill by the specified due date, or within 30 days of the date of the invoice or bill if a due date is not provided.

(c) All WEC obligations, interest fees, and penalties required by this subpart shall be paid to the Department of the Treasury by the WEC obligated party electronically in U.S. dollars, using an online electronic payment service specified by the Administrator.