Development of a SOFC/battery-hybrid system for distributed power generation in India

In recent years India faces demanding challenges in covering an aggressively increasing electricity consumption through economic growth and progressive consumer requirements. Renewable sources and small distributed power generators have been identified as one of the options to establish a diversified power supply infrastructure. The present situation offers promising opportunities for fuel cell systems, as ""grid-parity"" is not the common measure of competitiveness, but rather the installation speed and availability of reliable power sources.Contracted by the company h2e Power Systems Pvt. Ltd. based in Pune, India, Fraunhofer IKTS has developed a 1 kW(el) SOFC power generator during a three-year system engineering and technology transfer project. The fuel cell system is based on the CFY stack technology by Plansee SE and IKTS, incorporating state-of-the-art ESC with Scandia-doped Zirconia electrolytes. CFY-stacks have proven to be robust and reliable, showing power degradation rates below 0.6 % per 1.000 hours during endurance operation over 20.000 hours and a cyclization capability of more than 120 near-system cycles under full RedOx-conditions. For the SOFC power generator a CFY stack is integrated with a pre-reformer, a tail-gas oxidizer and heat exchangers into a HotBox-module following a novel concept for least-space-demanding reactor integration and flow distribution. Aside from compactness, a simple and robust, yet highly efficient system concept was set as the primary development goal for the project. To meet these requirements, two major design decisions have been introduced in the process layout, i.e. a rated fuel utilization in the stack of 85 % as well as a POX-air pre-heater for reducing the reformer air flow to lowest possible values. This approach leads to a water-less SOFC system with a net electrical efficiency above 40 %.In 2015, two Proof-of-Concept (PoC) prototype systems were commissioned and tested at IKTS. One of the PoC-prototypes was installed later at the customer's laboratory in Pune, India, for test and demonstration purposes. In Project Phase II, three improved demonstration prototypes are built at IKTS until May 2016, to be shipped to India for initial demonstration projects and field trials. At the same time, the technology transfer to the customer is initiated, in order to enable for a local manufacturing and deployment of SOFC systems in India. The project presentation will outline the development approach, system concept, control strategies and major technical achievements.