NOVELTY - Subsea power system comprises at least one fuel cell (10) near the sea floor and in communication with subsea devices.    USE - Fuel cells for use downhole in oil and gas wells, or subsea with offshore well, for power generation, powering electrical vehicles or other equipment.    ADVANTAGE - It is often not practical to power such devices by trailing power cables from another installation, due to distance involved, interference with other equipment or damage during well operation. Batteries do not offer an ideal solution, since they have limited life without recharge and can be unduly large for the available space. Fuel cells generate electricity without unwanted by products and have relatively high efficiency. However, fuel and/or oxidant pumps cab fail, leading to expensive repair or replacement. Further, pump operation uses some of the electricity generated by the cell. Water vapor needs to be removed as it is produced by the electrochemical reaction to continuously run the cell. The novel system avoid these problems by using present sea water to cool, and draining reaction products from and reactants along passageways formed by the cells to the cell, thus providing effective electrical power to operate downhole and subsea equipment.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for;    (1) A subsea field comprising a subsea processing facility, at least one production manifold, wireless communication system, and subsea power supply system as above;    (2) A method of cooling a subsea fuel cell by passing sea water through passageways through the cell;    (3) A method of removal and storage of water generated by a subsea fuel cell, containing at least one reservoir by providing drain holes (24,26) in communication with the reservoir;    (4) A subsea fuel cell comprising replaceable fuel and oxidant reservoirs;    (5) A subsea fuel cell comprising replenishable fuel (12) and oxidant (14) reservoirs; and    (6) A method for powering a subsea device by connecting a fuel cell to the device.    DESCRIPTION OF DRAWING(S) - The drawing shows a fuel cell apparatus comprising to cells in a stack.    fuel cell (10)    fuel vessel (12)    oxidant vessel (14)    reaction zone (16)    passageways(30) bore (24,26)