0001305227-13-001048 SC 13G/A 1 20130410 20130410 ATLANTIC POWER CORP 0001419242 4900 550886410 A1 1231 SC 13G/A 34 005-87139 13753231 ONE FEDERAL STREET FLOOR 30 BOSTON MA 02110 617-977-2400 ONE FEDERAL STREET FLOOR 30 BOSTON MA 02110 BlackRock Inc. 0001364742 6211 320174431 DE 0226 SC 13G/A 55 EAST 52ND STREET NEW YORK NY 10055 212-810-5300 55 EAST 52ND STREET NEW YORK NY 10055 BlackRock, Inc. 20060929 New BlackRock, Inc. 20060601 SC 13G/A 1 atlantic.power.corp.txt