This paper reports a new type of nanofluid, which is prepared by dispersing a hybrid nanomaterial single walled carbon nanotube–copper sulfide nanoparticles (SWNT–CuS NPs) into poly(styrene sulfonate) (PSS) solution, and its application for electricity generation. Its optical and thermal properties have been characterized, exhibiting significant improvement in optical extinction and temperature increase over water. In addition, a fluidic micropower generator is designed, fabricated and tested with the nanofluids of different concentrations. Measurements found that open circuit voltage by the fluidic micropower generator can be up to 1.6 mV with 900 μL nanofluid. Operation of a thermistor by the fluidic micropower generator has been demonstrated. Since hundreds and thousands of the micropower generators could be fabricated on a single chip by Si-based MEMS technology, the output power could be improved to the range of microwatts or milliwatts.