Liquefied natural gas (LNG) is regarded as the cleanest among fossil fuels due to its lower environmental impact. In power plants, it emits 50–60% less carbon dioxide into the atmosphere compared to regular oil or coal-fired plants. As the demand for a lower environmental footprint is increasing, fuel cells powered by LNG are starting to appear as a promising technology, especially suitable for off-grid applications, since they can supply both electricity and heating. This article presents a techno-economic assessment for an integrated system consisting of a solid oxide fuel cell (SOFC) stack and a micro gas turbine (MGT) fueled by LNG, that feeds the waste heat to a multi-effect desalination system (MED) on the Greek island of Patmos. The partial or total replacement of the diesel engines on the non-interconnected island of Patmos with SOFC systems is investigated. The optimal system implementation is analyzed through a multi-stage approach that includes dynamic computational analysis, techno-economic evaluation of different scenarios using financial analysis and literature data, and analysis of the environmental and social impact on the island. Specific economic indicators such as payback, net present value, and internal rate of return were used to verify the economic feasibility of this system. Early results indicate that the most sensitive and important design parameter in the system is fuel cell capital cost, which has a significant effect on the balance between investment cost and repayment years. The results of this study also indicate that energy production with an LNG-fueled SOFC system is a promising solution for non-interconnected Greek islands, as an intermediate carrier prior to the long-term target of a CO₂-free economy.

One of the main sources of global warming is greenhouse gasses; the most important of which is carbon dioxide. Reducing CO₂ emissions, and its utilization or storage, is a global challenge to tackle climate change. In this work, the operating conditions of the pilot CO₂ capture unit are studied using the ASPEN PLUS^® software. This study describes the methodology of the simulations and the main results. The unit consists of one scrubber and one stripper. For carbon dioxide absorption from gas streams, the aqueous solvent K₂CO₃ is used. The effect on the absorption of CO₂, and regeneration of carbon dioxide and potassium carbonate were studied by varying parameters of pressure, temperature, and concentration of solvent. For each parameter, three values were evaluated with the following ranges: pressure 0.3–1 bar; temperature 80–100 °C; and concentration of potassium carbonate 15–25 wt%. The optimum operating conditions of the pilot unit are pressure of 0.3 bar, stripper temperature of 100 °C, and solvent concentration of 15 wt%. Under these conditions, 99.91% CO₂ capture and 85.46% CO₂ regeneration were achieved. The present research aims to find the optimal operating parameters of the pilot plant to validate the model with the experimental data. In this way, the model parameterization can be used to design large-scale CO₂ capture units.