An apparatus for generating electrical power in a borehole penetrating the earth, the apparatus comprising: a first body configured to be disposed in the borehole, the first body comprising a first mechanical connector a second mechanical connector, a first electrical connector, and a second electrical connector, a second body comprising a first mechanical connector, a second mechanical connector, a first electrical connector, and a second electrical connector, wherein the first mechanical connector of the first body is configured to mechanically connect to the second mechanical connector of the second body having a second electrical generator, the second mechanical connector of the first body is configured to mechanically connect to the first mechanical connector of the second body, the first electrical connector of the first body is configured to electrically connect with the second electrical connector of the second body, and the second electrical connector of the first body is configured to electrically connect with the first electrical connector of the second body; a first electrical generator comprising a rotor and a stator disposed in the first body, the first electrical generator being in mechanical communication with the first mechanical connector of the first body at one end and the second mechanical connector of the first body at an opposing end, the first electrical generator being in electrical communication with the first electrical connector of the first body at one end and the second electrical connector of the first body at the opposing end; and a turbine wheel coupled to or integrated with the rotor and comprising one or more turbine blades that are configured to interact with fluid flowing through the borehole causing the turbine wheel to rotate and the rotor to rotate in order to generate the electrical power wherein the first body is coupled to the second body using the second mechanical connector and the second electrical connector of the first body and the first mechanical connector and the first electrical connector of the second body, wherein the second mechanical connector of the first body is interlocked with the first mechanical connector of the second body. a first body configured to be disposed in the borehole, the first body comprising a first mechanical connector a second mechanical connector, a first electrical connector, and a second electrical connector, a second body comprising a first mechanical connector, a second mechanical connector, a first electrical connector, and a second electrical connector, wherein the first mechanical connector of the first body is configured to mechanically connect to the second mechanical connector of the second body having a second electrical generator, the second mechanical connector of the first body is configured to mechanically connect to the first mechanical connector of the second body, the first electrical connector of the first body is configured to electrically connect with the second electrical connector of the second body, and the second electrical connector of the first body is configured to electrically connect with the first electrical connector of the second body; a first electrical generator comprising a rotor and a stator disposed in the first body, the first electrical generator being in mechanical communication with the first mechanical connector of the first body at one end and the second mechanical connector of the first body at an opposing end, the first electrical generator being in electrical communication with the first electrical connector of the first body at one end and the second electrical connector of the first body at the opposing end; and a turbine wheel coupled to or integrated with the rotor and comprising one or more turbine blades that are configured to interact with fluid flowing through the borehole causing the turbine wheel to rotate and the rotor to rotate in order to generate the electrical power wherein the first body is coupled to the second body using the second mechanical connector and the second electrical connector of the first body and the first mechanical connector and the first electrical connector of the second body, wherein the second mechanical connector of the first body is interlocked with the first mechanical connector of the second body.