The ambition of the BackCap proyect is to develop a new process to capture CO2 from amortized combustion power plants, retrofitted for back-up power provision in highly renewable electricity networks, while supplying CO2 for use or storage. To address the escalation of CO2 capture cost in such low capacity factor system, BackCap uses in-duct Ca(OH)2 injection for CO2 capture during the brief power production periods. The resulting CaCO3 will be stored and used as a steady source of CO2 and CaO by oxy-fuel calcination. 


  • To obtain carbonation reaction kinetics and CO2 carrying capacities of Ca(OH)2 sorbents under relevant reactor conditions during the CO2 capture step.

  • To obtain key operation data with respect to the loss of active sorbent material when cycling the sorbent between of Ca(OH)2 and CaCO3.

  • To demonstrate viability of carbonator reactors adapted to Ca(OH)2 sorbent properties (particle/pellet size, Ca(OH)2/CaO ratio,  specific surface).

  • TRL4-5 proof of concept of Ca(OH)2 entrained bed carbonation reactor with high CO2 capture efficiencies (>95%) in a pilot prototype.

  • To test sorbent regeneration from carbonated particles of Ca(OH)2, using oxy-fuel combustion.

  • To design a viable process for CO2 capture from amortized coal power plants operated in back-up mode by minimizing the cost of capture at very low capacity factors, allowed by the use of modest scale and well-integrated calcination and hydration operations.

  • To evaluate cost and economic viability of a full system including all BackCap elements.

  • To quantify impacts of the new technology in future electricity grids with 80-100% share of renewables, including a benchmarking against Power-to-Fuel-to-Power and other backup options.

This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 101034000

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Dr. Borja Arias
CO2 Capture group, Carbon Science and Technology Institute (INCAR – CSIC)
C/ Francisco Pintado Fe, 26, 33011 OVIEDO, Spain