Power generation systems and associated methods for generating electric power using a cascaded fuel cell are provided. The power generation system may include a first fuel cell, a second fuel cell, a splitting mechanism, a first fuel path, and a second fuel path. The First fuel cell is configured to generate first anode and first cathode tail gas streams. The splitting mechanism is configured to split the first anode tail gas stream into first and second portions. The first fuel path is configured to receive hydrocarbon fuel stream downstream of splitting mechanism, mix with the first portion to form a mixed stream, and circulate the mixed stream to the first fuel cell. The second fuel path is configured to feed the second portion to the second fuel cell. The first and second fuel cells are configured to generate electric power by using the mixed stream and the second portion respectively.