Calcium looping is a post-combustion CO2 capture scheme that uses a solid CaO-based sorbent to remove CO2 from flue gases, e.g. from a power plant, generating a concentrated stream of CO2 suitable for geological sequestration. The scheme exploits the reversible gas-solid reaction between CO2(g) and  CaO(s) to form CaCO3(s). Calcium looping has a number of advantages compared to closer-to-market capture schemes, including: the use of circulating fluidized bed reactors– a mature technology at large scale; sorbent derived from cheap, abundant and environmentally benign limestone and dolomite precursors; and the relatively small efficiency penalty that it imposes on the power generation process. A further advantage is the synergy with cement manufacture, which potentially allows for decarbonization of both cement manufacture and power production. Finally, a future application of pre-combustion calcium looping is the production of clean hydrogen gas for a hydrogen fuel economy.