A hybrid power generation apparatus comprising: a first RED (reverse electro dialysis) part configured to generate electricity due to a concentration difference between a high concentration solution and a low concentration solution; and including a first electrode and a second electrode electrically connected to the first electrode; and a second RED part configured to generate electricity due to the concentration difference between the solutions and including a third electrode disposed to face the second electrode to form a space portion between the third electrode and the second electrode and a fourth electrode electrically connected to the third electrode, wherein the space portion includes one or more flow channels through which a fluid is flowable, and when each of the first RED part and the second RED part generate the electricity, the first RED part and the second RED part are arranged such that a potential difference caused by the second electrode and the third electrode is applied to the space portion, wherein at least one of the first RED part and the second RED part and the space portion are connected such that a solution flowing in the flow channel is supplied to at least one of the first RED part and the second RED part or are provided such that a solution discharged from at least one of the first RED part and the second RED part is supplied to the flow channel, wherein, in the space portion, an ion exchange membrane (311, 312) is disposed adjacent to each of facing surfaces (102a, 201a) of the second electrode and the third electrode, wherein the space portion is defined as a space between facing surfaces and of the second electrode and the third electrode, wherein the apparatus is configured such that one or more among saltwater, seawater, brackish water, and a mixed solution including one or more thereof are supplied to the space portion, and, when the potential difference is applied to the space portion, deionization is performed, wherein the flow channel is provided such that a flowing solution comes into contact with the facing surfaces and of the second electrode and the third electrode, and wherein the apparatus is configured such that when the low concentration solution and the high concentration solution are introduced into the first RED part and second RED part, a potential difference is generated due to a concentration difference between the low concentration solution and the high concentration solution, and the potential is applied to the space portion. a first RED (reverse electro dialysis) part configured to generate electricity due to a concentration difference between a high concentration solution and a low concentration solution; and including a first electrode and a second electrode electrically connected to the first electrode; and a second RED part configured to generate electricity due to the concentration difference between the solutions and including a third electrode disposed to face the second electrode to form a space portion between the third electrode and the second electrode and a fourth electrode electrically connected to the third electrode, wherein the space portion includes one or more flow channels through which a fluid is flowable, and when each of the first RED part and the second RED part generate the electricity, the first RED part and the second RED part are arranged such that a potential difference caused by the second electrode and the third electrode is applied to the space portion, wherein at least one of the first RED part and the second RED part and the space portion are connected such that a solution flowing in the flow channel is supplied to at least one of the first RED part and the second RED part or are provided such that a solution discharged from at least one of the first RED part and the second RED part is supplied to the flow channel, wherein, in the space portion, an ion exchange membrane (311, 312) is disposed adjacent to each of facing surfaces (102a, 201a) of the second electrode and the third electrode, wherein the space portion is defined as a space between facing surfaces and of the second electrode and the third electrode, wherein the apparatus is configured such that one or more among saltwater, seawater, brackish water, and a mixed solution including one or more thereof are supplied to the space portion, and, when the potential difference is applied to the space portion, deionization is performed, wherein the flow channel is provided such that a flowing solution comes into contact with the facing surfaces and of the second electrode and the third electrode, and wherein the apparatus is configured such that when the low concentration solution and the high concentration solution are introduced into the first RED part and second RED part, a potential difference is generated due to a concentration difference between the low concentration solution and the high concentration solution, and the potential is applied to the space portion.