Fuelling power plants by natural gas: An analysis of energy efficiency, economical aspects and environmental footprint based on detailed process simulation of the whole carbon capture and storage system

In view of the low-carbon transformation of the power sector, natural gas-fired power generation is the only technology, among fossil resources, that will continue to provide an important source of flexibility for the power system in the coming years. However, the carbon dioxide emissions produced by the operation of such plants call for carbon capture and storage equipment, whose deployment needs to be assessed and compared with the main renewable technologies: wind power and photovoltaics. This work uses process simulation in order to assess two different carbon capture processes: a traditional one, based on monoethanolamine, and an innovative one, based on hot potassium carbonate. Process simulation is also used for the transportation of carbon dioxide to the sequestration site. Mass and energy balances from the simulations are then used for the calculation of the Energy Return on Energy Invested, the Levelized Cost of Energy and as inputs for the Life Cycle Assessments of both alternative designs. The life cycle analyses of the considered power technologies exhibited higher contributions due to fossil-based power plants towards climate-related impact categories, while renewable sources were revealed to be more burdensome for the exploitation of mineral resources. The calculated Energy Return on Energy Invested for gas-fired power plants with carbon capture and storage is between 5.2 and 12.4, comparable with the values of photovoltaics and wind power. On the other hand, their Levelized Cost of Energy is between 10.2 and 20.0 eurocent per kilowatt-hour, much higher than that of renewables. The conclusion is that, at present, the sustainability of gas-fired power stations equipped with carbon capture and storage should be carefully considered and not taken for granted.