Update of Techno-Economic Benchmarks for Fossil Fuel Power Plants with CO2 Capture

Abstract

Carbon capture and storage (CCS) has long been recognized as a key component of an effective mitigation strategy to decarbonize the power and industrial sectors. For many reasons, however, the commercial deployment of CCS technologies has been slow and must accelerate to contribute effectively to mitigating climate change. This paper presents the outcome of a study that Amec Foster Wheeler Italiana, a Wood Company, performed on behalf of IEAGHG, aimed at updating the technical and economical assessment of coal and natural gas fired power plants with and without CO2 capture, considering the benefits of recent technology improvements. The work has focused on ultra-supercritical pulverized coal (USC PC) boiler and natural gas combined cycle (NGCC) power plants, with and without CO2 capture. Post combustion capture based on solvent scrubbing only has been considered; this is currently the commercially leading option for capture on both pulverized coal and natural gas-fired power plants. Two different capture unit designs are studied: a 90% CO2 recovery scenario, and a high capture rate scenario (around 99%). Starting from the benchmark NGCC cases described above, the work has also addressed: • The impacts of Flue Gas Recirculation (FGR) on power plant performances and economics. The recirculation of part of the flue gas back to the GT compressor has the beneficial effects of enriching the exhaust gas in CO2 and significantly reducing the gas throughput of the absorption section in the CO2 capture unit, but also shows some drawbacks, such as the cost of the recirculation system and a slight efficiency drop. • Improvements to the operational flexibility of both natural gas and coal fired power plants with carbon capture from a simplified techno-economic optimization standpoint, updating the main outcomes of the work presented in “Operating flexibility of power plants with CCS” (2011, Foster Wheeler) with state-of-the-art technologies. The trade-off between flexibility and efficiency is also analyzed for the coal cases, including a literature review of the possible impacts on operating flexibility of adopting Advanced-Ultra Super Critical (A-USC) technologies (700°C). • Consideration of mid-term future advancements on power generation technologies for the NGCC plant, including the use of novel improved materials in the hot gas path of the for the gas turbine and integration with Molten Carbon Fuel Cells (MCFCs), in which hydrogen is provided via natural gas steam reforming (using MCFC waste heat). The MCFC, besides contributing to power generation, allows separation of CO2 from the NGCC flue gas and its release into a syngas stream that needs a relatively simple purification method to remove the CO2 (like cryogenic technology) and can then be re-covered as auxiliary fuel to the power island.