Acumentrics-Nippon SOFC System Passes 50% Efficiency Threshold For Operational Viability In Japanese Tests

December 16, 2007 by Jeff Shepard

A solid oxide fuel cell (SOFC) system developed jointly by Acumentrics & Nippon Steel Engineering Co. Ltd. has demonstrated a net electrical efficiency of 52% dc (42% ac) in extended operation, and an overall efficiency of 83% in tests conducted as part of the Japanese New Energy and Industrial Technology Development Organization ("NEDO") program.

"The achievement of over 50% electrical efficiency in a small scale system is well above what is achievable by similar sized diesel generator sets, which typically operate at an efficiency less than 30%." said Acumentrics CTO and Senior Vice-President, Dr. Norm Bessette. "Now that we have demonstrated this efficiency rate in a small system, broader use of SOFC fuel cell units for distributed residential power and heating, and for megawatt-size commercial and utility applications has moved within reach. Although hurdles remain in demonstrating operational longevity and equipment cost-reductions in large scale manufacturing, wider commercial viability is definitely coming into sight." He also speculated that the 52% net dc efficiency rate could represent a new record for generators smaller than 10kW.

The 8.8 kW system, which used Acumentrics’ tubular solid oxide technology, successfully completed 3,000 hours of operation fueled with natural gas using steam reforming, an efficient method of breaking down the natural gas so that it may be converted to electricity by the fuel cell. According to the company, steam reforming is considered superior to the commonly used method of partial oxidation as it allows the system to achieve higher efficiencies, which is key to reducing green house gas emissions.

"By demonstrating an integrated system that uses steam reforming, Acumentrics Japan has achieved a significant technical milestone," according to Bessette. "The system which is based on the same cell technology used in the Acumentrics system evaluated in the U.S. Department of Energy’s Solid State Energy Conversion Alliance (SECA) program. The NEDO tests show the increased efficiency that can be achieved by moving from partial oxidation to steam reforming � 37% to 52% � and demonstrates that the natural gas-to-AC electricity efficiency of 50% long promised by SOFCs is achievable in small scale sizes."

The SOFC development program sponsored by NEDO is aimed at facilitating the mass commercialization of SOFC technology.