Exhibit 3.7

                            CERTIFICATE OF FORMATION

                                       OF

                        PSEG ENERGY RESOURCES & TRADE LLC

            This Certificate of Formation of PSEG Energy Resources & Trade LLC
(the "LLC"), dated as of June 16, 1999, is being duly executed and filed by
Bernard J. Kelley, as an authorized person, to form a limited liability company
under the Delaware Limited Liability Company Act (6 Del.C. subsection 18-101, et
seq.).

            FIRST. The name of the limited liability company formed hereby is
PSEG Energy Resources & Trade LLC.

            SECOND. The address of the registered office of the LLC in the State
of Delaware is c/o The Corporation Trust Company, 1209 Orange Street,
Wilmington, New Castle County, Delaware 19801.

            THIRD. The name and address of the registered agent for service of
process on the LLC in the State of Delaware is The Corporation Trust Company,
1209 Orange Street, Wilmington, New Castle County, Delaware 19801.

            IN WITNESS WHEREOF, the undersigned has executed this Certificate of
Formation as of the date first above written.

                                                         /s/ Bernard J. Kelley
                                                         -----------------------
                                                         Name: Bernard J. Kelley
                                                         Authorized Person