This work evaluates the environmental impact of conventional and calcium looping processes implemented with CO2 separation to gain broad insight and identify opportunities for future improvement. These systems are assessed at multiple scales: equipment, value chain and economy, and emissions of CO2, water use, land use, and energy return on investment are estimated. The difference in the energy quality of hydrogen and electricity products is considered in developing aggregate metrics. Calcium looping is found to be superior due to its smaller life cycle impacts. However, this process has a smaller energy return on investment due to the higher energy and resource requirements in the calcination and air separation steps. Future efforts for reducing the energy intensity of these steps by developing new technologies and optimizing existing methods are recommended.