Readiness evaluation of SOFC-MGT hybrid systems with carbon capture for distributed combined heat and power

The aggravation of climate change calls for the timely development and implementation of highly efficient, renewable, zero- or negative-emission energy solutions with high technological readiness and feasibility levels. Solid oxide fuel cells (SOFC) constitute an appealing solution since they are close to commercial viability and can generate electricity and heat from a wide variety of fuels, for instance gas from renewable sources. In this paper, we consider the coupling of SOFC with Brayton cycles via micro gas turbines (MGT) due to their suitability for a compact small-scale energy system (10–100 kWe) and their high readiness level as stand-alone systems and in combination with suitable carbon capture and storage (CCS) technologies. An integrative literature review approach is used to qualitatively evaluate different SOFC-MGT integration strategies and CCS to devise a suitable small-scale SOFC/MGT-CCS system. A promising layout of a hybrid system based on atmospheric pressure SOFC and MGT has been identified, which uses an inverted Brayton cycle to expand the SOFC outlet gases. This system has the potential to achieve similar efficiency as the widely researched pressurized system with less complexity. Further, implementing an oxy-combustion process between the SOFC and the MGT inlet, a pure stream of CO2 is obtained, easing its capture.