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Summary Integrating biomass energy generation with carbon capture will result in “carbon neutral” to “carbon negative” technology. Countries like India and China possess significant reserves of limestone. Calcium looping (CaL) technology can prove to be a promising option for carbon capture in these countries. The present work aims at improving the performance of CaL‐integrated biomass‐fired power plant (BFPP) by exploring different looping configurations. In this study, (i) standalone BFPP, (ii) conventional CaL (single stage), and (iii) double CaL‐integrated BFPP have been systematically evaluated. A comparative performance evaluation of these three plants in terms of energy, exergy and ecological assessment, has been carried out. A detailed parametric study and unit‐wise exergy analysis of the best configuration among the three are presented to identify the scope for further improvement in efficiency and energy savings.

Energy plays a pivotal role in industrial development of any country. At present, most of the countries are utilizing fossil fuels, mainly coal and natural gas as energy sources for power production. However, these sources emit high amounts of carbon dioxide (CO 2 ) into the atmosphere resulting in global warming. Hence, the fossil fuel-based thermal power plants need to be integrated with CO 2 sequestration and utilization processes for sustainable power production. In this work, four natural gas combined cycle (NGCC) power plant configurations are proposed-two with CO 2 capture and sequestration (single and double calcium looping units) and two with CO 2 capture and utilization (for production of dimethyl ether). Energy, exergy, environmental, and economic analyses are carried out to assess the performance of the proposed novel configurations against the conventional NGCC power plant. These analyses reveal that the NGCC power plant integrated with double calcium looping unit captures 91.32% of CO 2 with an energy penalty of 6.73%. The proposed CO 2 capture and utilization integrated configurations have low electrical power output; however, the conversion of CO 2 to high energy density dimethyl ether (DME) product resulted in overall energy and exergy efficiency gain. The CO 2 capture and utilization configuration integrated with solar energy is able to convert the total captured CO 2 to DME and makes the process sustainable. K E Y W O R D Scalcium looping unit for CO 2 capture, DME production from CO 2 , economic analysis, energy and exergy analysis, NGCC power generation

Coal still remains to be the major resource for power production in many countries. Supercritical (SupC) steam generated coal-fired power plants (CFPPs) are found to be superior to subcritical steam generated plants in terms of the overall plant efficiency. Chemical looping combustion (CLC), which is an indirect combustion between fuel and air, is an innovative, inherent CO2 capture and recent technology for power production. In this study, two cases -conventional SupC CFPP without CO2 capture and CLC-based SupC CFPP for high-ash Indian coal have been simulated. Detailed energy and exergy analyses are conducted for both the cases and compared. The study shows that CLC-based capture technology has less energy penalty with Fe2O3 oxygen carrier and little energy gain with CuO and NiO carriers compared to conventional plant without CO2 capture. This study demonstrates the superiority of CLC-based SupC CFPP for CO2 capture over the conventional plant.

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