AP9 - Biogas-CHP using fuel cell

Starting point for this research package is the fact, that the SOFC technology has reached a development stage allowing for the production in large quantities in the years 2011-13 due to the dedication of big European companies (Rolls Royce, Siemens, TOFC). The costs are assumed to reach 1000-1500 Euro/kW, a common value for stationary applications.
A transfer to this new technology has to imply further advantages for the end customers. Therefore, a system concept with several outstanding properties is proposed. This concept includes higher efficiencies of the power production with gas, higher spreading between the minimum and maximum ratio of power- to heat-production, and an efficient decentralised production of synthesis gas or hydrogen all of them at the same price level as conventional plants. For this purpose it is mandatory to apply novel technologies.

Therefore, a target of this research project is the analysis of the new crucial components. These components are the SOFC-stack with TEG-waste-heat-utilisation and the innovative gas reforming of a SOFC-CHP with a maximum electrical efficiency of 60%. These results will be demonstrated by a combination of experiments using evaluation models of a SOFC-stack with TEG-elements and a gas reformer with anode loop. The scale of these evaluation models will be in the power range of 1-2 kW. The results of the evaluation models will be evaluated and scaled to the determined optimum size of a CHP-plant using a grid integration study.

After the analysis of current and past projects on decentralised fuel-cell-CHPs (approximately 10 decisive national and international projects), a detailed description of the system requirements and the applicable frameworks for a SOFC-CHP-system as well as the possible areas of application will be done. Based on the specifications research on the following topics will be undertaken: gas reforming applying anode tail gas loops for efficiency improvement, reduction of the water demand, identification of the most suitable TEG-semiconductor materials for SOFC applications. Further topics comprise the elaboration of suitable contact layers and protection layers, assembly of TEG-elements in technical arrangement and integration into the insulation board of the SOFC-stack.

Subsequently, the integration of the components SOFC-stack, TEG-elements and gas reformer in one evaluation model will be done. Additionally, this evaluation model will be operated during a longer period (at least 4-6 weeks) and accompanied by simulation of the so called “node load in the network” (=load cycle during the virtual integration into an energy network).

Finally, a validation of the system layout together with a technical and financial assessment for the system SOFC-CHP using the experimental results will be accomplished. Furthermore, conclusions and recommendations for policy and further technology developments will be elaborated based on the results of the fundamental study.