I think your question is "why burn fossil fuels for energy, then use more energy to clean their exhaust streams, instead of using that energy in the first place

I think your question is "why burn fossil fuels for energy, then use more energy to clean their exhaust streams, instead of using that energy in the first place instead of fossil fuels?" If so, I think the purpose of this research is to process the exhaust streams of industrial processes that create lots of CO2 for reasons other than energy. For example, steel production produces a lot of CO2 due to chemical reactions used to remove impurities from iron, even if the blast furnace runs entirely on renewable energy. This process would, hypothetically, allow us to input more renewable energy to capture the exhaust CO2 and make steelmaking more carbon neutral.