A pressure compensating system (1) for a dual fluid flow system, wherein the pressure compensating system (1) comprises: a fluid pipe (3) having a first fluid pipe portion (3a) and a second fluid pipe portion (3b), wherein the first fluid pipe portion (3a) has a first fluid inlet (5a) and a first fluid outlet (7a) for a first fluid flow (O2), wherein the second fluid pipe portion (3b) has a second fluid inlet (5b) and a second fluid outlet (7b) for a second fluid flow (H2) separate from the first fluid flow (O2), and a pressure compensator (11) arranged in the fluid pipe (3), separating the first fluid pipe portion (3a) and the second fluid pipe portion (3b), wherein the pressure compensator (11) is configured to move in the fluid pipe (3) between the first fluid outlet (7a) and the second fluid outlet (7b) to thereby at least partially obstruct one of the first fluid outlet (7a) and the second fluid outlet (7b) in response to a pressure differences between the first fluid pipe portion (3a) and the second fluid pipe portion (3b) to provide pressure compensation between the first fluid pipe portion (3a) and the second fluid pipe portion (3b).