Calcium looping is based on the simple premise of the reversible reaction between CO[subscript 2] and CaO. This reaction can be used for separation of CO2 from a mixture of gases; most notably the technology finds applications in CO[subscript 2] removal from gas streams in fossil fuel-based energy systems. This article gives a brief overview of the calcium looping process and uses the example of a coal-fired power plant for discussing several aspects, including material balances and energy requirements. This article, which is based on an important topic of current research, is written in a format that can be directly adopted for a project in introductory chemical engineering courses.