existing power plants, rather than requiring new plants to be built. The IEA sees power plants as an important target for carbon capture, and has set the goal to have all fossil fuel based power plants deploy CCS systems by 2040. However, power plants are expensive to build, and long lived. Retrofitting of post-combustion capture systems, such as Ca-looping, seems to be the only politically and economically viable way to achieve the IEA's goal. A further political advantage is the potential synergy between calcium looping and cement production. An IEA report concludes that to meet emission reduction goals, there should be 450 CCS projects in India and China by 2050. However, this could be politically difficult, especially with these nations' numerous other development goals. After all, for a politician to commit money to CCS might be less advantageous than to commit it to job schemes or agricultural subsidies. Here, the integration of calcium looping with the prosperous and (particularly with infrastructure expansion in the developing world) vital cement industry might prove compelling to the political establishment. This potential synergy with the cement industry also provides environmental benefits by simultaneously reducing the waste output of the looping process and decarbonizing cement production. Cement manufacture is energy and resource intensive, consuming 1.5 tonnes of material per tonne of cement produced. In the developing world, economic growth will drive infrastructure growth, increasing cement demand. Deploying a waste product for cement production could therefore have a large, positive environmental impact. Environmental implications The starting material for calcium looping is limestone, which is environmentally benign and widely available, accounting for over 10% (by volume) of all sedimentary rock. Limestone is already mined and cheaply obtainable. The mining process has no major known adverse environmental effects, beyond the unavoidable intrusiveness of any mining operation. However, as the following calculation shows, despite integration with cement industry, waste from Ca-looping can still be a problem. From the environmental and health standpoint, Ca-looping compares favorably with amine scrubbing. Amine scrubbing is known to generate air pollutants, including amines and ammonia, which can react to form carcinogenic nitrosamines. Calcium looping, on the other hand, does not produce harmful pollutants. In addition, not only does it capture CO2, but it also removes the pollutant SO2 from the flue gas. This is both an advantage and disadvantage, as the air quality improves, but the captured SO2 has a detrimental effect on the