Fuel cells plumb new depths

They have already been used in space and now low-carbon fuel cells are set to break another barrier after UTC Power announced it has inked a deal to provide a new 300KW fuel cell for use in the Spanish Navy's S-80 submarine.

The company said the deal with Spanish shipbuilder Navantia represented one of the largest deals in its history and would see it develop a new proton exchange membrane (PEM) fuel cell for the submarine.

"One of the places that fuel cells make sense is in submarines because, as in space, it is difficult for them to access air to drive a combustion engine," explained Henry DeRonck, general manager for space and defence at the fuel cell specialist. "The concept has been there for a long time, but the fuel cells have not been good enough. Now, with new PEM cells beginning to be commercialised, the technology is there."

UTC Power said that the 300KW fuel cell should be powerful enough to drive a 2,500 tonne submarine and would provide a number of advantages over a conventional diesel-powered submarine.

"Countries without nuclear submarines have diesel electric engines, which have to use a snorkel at shallow depths to get air to the engine, and when they dive they run off batteries that are typically good for just two days," explained DeRonck. In contrast, the fuel cell runs off pure oxygen and reformed ethanol that is converted into hydrogen, potentially allowing the submarine to stay under water for far longer.

DeRonck said he could not give exact details on how long the submarine could stay submerged, but admitted that the goal of the project was to allow the fuel cell to operate for two to three weeks without recharging.

As well as delivering operational improvements, the fuel cell should also boast a "lower environmental signature" than conventional propulsion systems, according to DeRonck, although he admitted this was not a factor in the Spanish Navy's decision.

"There is exhaust in the form of CO2 from the ethanol process, but PEM cell is relatively green because it is more efficient than an internal combustion engine," he explained, adding that work was continuing to find a low-carbon, low-cost means of manufacturing hydrogen.

UTC Power insisted that the high power load from the new cell should also serve to highlight the growing number of applications for fuel cell technology. "The power rating is 300KW and that is a good size when you consider the typical household uses 10KW," said DeRonck. "There is a lot of potential for using PEM cells in both trucks and at stationary locations like offices."