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IEA Greenhouse Gas R&D Programme

Introduction

 

New Carbon Capture technologies are emerging and these must be techno-economically compared with well-established systems used for the power sector. IEAGHG identified the need of a comprehensive assessment of emerging CO2 capture technologies for this sector, and an evaluation of their potential to reduce costs. The objectives of this technical study were:

 

  • to update the CO2 capture benchmark technology and its enhancement over the adopted 30w.t.% MEA (Monoethanolamine) -based chemical absorption technology currently used.

 

  • to review the CO2 capture technologies used in the power sector, their current status and trajectory

 

  • to assess the potential of emerging CO2 capture systems to reduce the Levelised Cost of Electricity (LCOE); and identify risks and barriers on the path of different technologies to reaching TRL 9 (full commercial operation).

 

  • to assess techno-economically a number of selected CO2 capture technologies for coal and gas-fired power plants. 

 

  • The techno-economic review covered Ca-looping, membrane-system (MTR Polaris), Allam cycle, and chemical absorption (using 30w.t.% MEA (Monoethanolamine) and 40w.t.% PZ (Piperazine) + AMP (2-amino-2-methyl-1-propanol) solution) for gas-fired power plants, and Ca-looping, membrane-system (MTR Polaris), solid sorbent-system (Veloxotherm), liquid-liquid separating system (DMX), and chemical absorption (using 30w.t.% MEA and 40w.t.% PZ+AMP) for coal-fired power plants.  Coal-fired and gas-fired power plants without CO2 capture systems were assessed for comparison.

Key Messages

 

  • A (PZ + AMP) solution (40w.t.%, 1:2 Molar ratio) is proposed as the new benchmark.

 

  • The new benchmark solution (PZ+AMP) shows a CO2 avoidance cost reduction of 22% for coal-fired, and 15% for gas-fired power plants, compared to a 30w.t.% MEA-based system.  The reboiler heat duty (heat energy required to regenerate the solvent) of the new benchmark is similar to that of current commercial blends.

 

  • Chemical absorption is still leading the list of emerging CO2 capture technologies as it has reached TRL 9 compared to the lower TRLs of other technologies.

 

This study has investigated the progress of several post-combustion systems and shown further technological development is possible.  Moreover, oxyfuel turbines are expected to advance in the near future.

 

  • Front-end engineering design (FEED) research studies show that there is significant potential to reduce the LCOE in electrochemical separation (fuel-cells).  An estimated 30% reduction in the LCOE has been predicted but this claim requires confirmation through large-scale demonstration projects.

 

  • Other capture systems with medium LCOE reduction potential (10%-30%) are based on chemical absorption with water-lean, precipitating or catalysed sorbents, membrane separation, PSA (pressure-swing adsorption), TSA (temperature-swing adsorption), calcium looping (Ca-looping), and cooling and liquefaction.  Moreover, pressurized oxyfuel combustion, chemical-looping combustion and SEWGS (sorption-enhanced water-gas shift) are also expected to show some LCOE reduction (<10%).

 

  • The techno-economic assessment shows the impact of regional, financial and economic conditions on the LCOE obtained by the different CO2 capture technologies applied to gas-fired and coal-fired power plants.

 

  • For coal-fired power plants, the new benchmark solution (40w.t.% PZ + AMP) shows the lowest LCOE, while the Allam cycle would be, economically, the most favourable option for gas-fired power plants.  However, in both gas and coal-fired power plants the other CO2 capture alternatives could be more favourable under specific financial and economic conditions.

 

  • Based on the results from this study, it is recommended that the most promising technologies should be followed-up, and more detailed cost evaluation studies pursued, together with an evaluation of their extended value within electricity supply, grid distribution and broader decarbonisation goals.
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