Exhibit 4.7(b) Facility Lease Agreement (Dickerson L2) between Southern Energy Mid-Atlantic, LLC, as Lessee, and Dickerson OL2 LLC, as Owner Lessor, dated as of December 19, 2000 Facility Lease Agreement (Dickerson L3) between Southern Energy Mid-Atlantic, LLC, as Lessee, and Dickerson OL3 LLC, as Owner Lessor, dated as of December 19, 2000 Facility Lease Agreement (Dickerson L4) between Southern Energy Mid-Atlantic, LLC, as Lessee, and Dickerson OL4 LLC, as Owner Lessor, dated as of December 19, 2000