Fuel cell apparatus and method for downhole power systems

A drill string for excavating a wellbore, the drill string comprising:

• a turbine configured to rotate due to impingement of drilling mud on one or more turbine blades;
• a generator in operable communication with the turbine, wherein the generator is configured to generate electricity using rotation of the one or more turbine blades;
• and
• a fuel cell system configured to operate in a discharge stage and a charge stage, wherein the fuel cell comprises:
• an oxygen supply;
• a hydrogen supply;
• a fuel cell stack that comprises:
• a first electrode;
• a second electrode;
• a proton exchange membrane located between the first electrode and the second electrode;
• and
• at least one water storage medium located between the proton exchange membrane and the second electrode;
• wherein, during the discharge stage, the fuel cell system is configured to (i) generate electricity within the fuel cell stack by producing an electrochemical reaction between hydrogen and oxygen provided from the oxygen supply and hydrogen supply and (ii) retain water produced by the electrochemical reaction within the fuel cell stack by storing the water in the at least one water storage medium;
• wherein, during the charge stage, the fuel cell system is configured to generate hydrogen and oxygen within the fuel cell stack by using the electricity generated by the generator to electrolyze the water stored in the at least one water storage medium.