cement that is generated from the calcium looping wastes. Advantages and drawbacks Advantages of the process Calcium looping is considered as potential promising solutions to reduce CO2 capture energy penalty. There are many advantages from the calcium looping methods. Firstly, the method has been proved to yield a low efficiency penalties (5-8% points) while other mature CO2 capture systems yield a higher efficiency penalties (8-12.5%). Moreover, the method is well suited for a wide range of flue gases. Calcium looping is applicable for new builds and retrofits to existing power stations or other stationary industrial CO2 sources because the method can be implemented using large-scale circulating fluidized beds while other methods such as amine scrubbing is required a vastly upscale solvent scrubbing towers. In addition, crushed limestone used in calcium looping as the sorbent is a natural product, which is well distributed all over the world, non-hazardous and inexpensive. Many cement manufacturers or power plants located close to limestone sources could conceivably employ Calcium looping for CO2 capture. The waste sorbent can be used in cement manufacture. Drawbacks Apart from these advantages, there are several disadvantages needed to take into considerations. The plant integrating Ca-Looping might require a high construction investment because of the high thermal power of the post-combustion calcium loop. The sorbent capacity decreases significantly with the number of cycles for every carbonation-calcination cycle so the calcium-looping unit will require a constant flow of limestone. In order to increase the long-term reactivity of the sorbent or to reactivate the sorbent, some methods are under investigation such as thermal pretreatment, chemical doping and the production of artificial sorbents. The method applying the concept of fluidized bed reactor, but there are some problems causing the uncertainty for the process. Attrition of the limestone can be a problem during repeated cycling. Benefits of calcium looping compared with other post-combustion capture processes Calcium looping compares favorably with several post-combustion capture technologies. Amine scrubbing is the capture technology closest to being market-ready, and calcium looping has several marked benefits over it. When modeled on a 580 MW coal-fired power plant, Calcium looping experienced not only a smaller efficiency penalty (6.7-7.9% points compared to 9.5% for monoethanolamine and 9% for chilled ammonia) but also a less complex retrofitting process. Both technologies would require the plant to be retrofitted for adoption, but the calcium looping retrofitting process would result in twice the net power output