Exhibit 10-A-33.1 Transco Gas Marketing Company September 13, 1993 Public Service Company of North Carolina, Inc. 800 Cox Road Gastonia, North Carolina 28053 Attention: Vice President, Gas Supply and Transportation Re: Amendment to that certain "AMENDED AND RESTATED GAS SALES AGREEMENT" by and between Transco Energy Marketing Company, as Seller, and Public Service Company of North Carolina, Incorporated, as Buyer, dated November 1, 1990 Gentlemen: Pursuant to our previous discussions, please accept this letter as amending the above-named agreement as follows: 1. Effective November 1, 1993 - Article I, Section l.Ol(g) shall be amended to reduce the Daily Contract Maximum from twenty thousand (20,000) dt of gas per day to ten thousand (10,000) dt of gas per day; and, 2. Effective November 1, 1992, Article VIII, Section 8.01(a) shall be amended to reduce the eighteen cents ($.18) reference therein to ten cents ($.10). All other terms and conditions of the above-named agreement shall remain in full force and effect. Public Service Company of North Carolina, Inc. September 13, 1993 Page Two If the foregoing represents your understanding of the transaction contemplated by the parties hereto, please so indicate by executing both copies of this letter and returning one (1) to the undersigned. Sincerely, TRANSCO ENERGY MARKETING COMPANY /s/H. Dean Jones II H. Dean Jones II Senior Vice President HDJ/MJS/dms/9300 1 Agreed to and Accepted this the 20 day of Sept., 1993. PUBLIC SERVICE COMPANY OF NORTH CAROLINA, INCORPORATED By: /s/Franklin H. Yoho Title: Franklin H. Yoho Vice President Corporate Development & Gas Supply