Energy conversion by the mechanism of electrokinetics is investigated. A device capable of converting either electrical power into pumping power or pumping power into electrical power in the steady state is studied. The basic equations coupling voltage, pressure, current and flow rate are established and simplified in the light of existing experimental evidence. Operating characteristics for both the fluid pumping and the electrical generation mode are determined and illustrated by example problems. The results indicate that with water as the working fluid, conversion efficiencies of only 0.392 percent are possible.