Sustainability analysis of a solar-driven calcium looping plant for thermochemical energy storage

Sustainable development is essential to ensure that future generations enjoy the same or better standard of living as today's society. Clean energy will play an important role in this. Concentrated solar power is one of the cleanest ways to harness solar power and convert it into useable energy like electricity. However, due to the intermittent nature of solar power production, concentrated solar power needs to be coupled with energy storage to ensure the ability to produce and release electricity during peak demand periods. Calcium looping for thermochemical energy storage is an emerging technology that uses calcium carbonate, a highly abundant and inexpensive material, to store energy in the form of calcium oxide and carbon dioxide. A sustainability analysis of a solar-driven calcium looping plant for thermochemical energy storage process is performed in this work. Several process alternatives, previously modelled in Aspen Plus®, are assessed using three sustainability analysis tools, GREENSCOPE, SimaPro, and OpenLCA. Nine process alternatives are considered, including the use of sorbent purge, water vapor as fluidization fluid at the calciner, and different operating temperatures in the calciner. All the analysis tools identified the process alternative using total sorbent purge, water vapor as fluidization fluid and a calciner temperature of 800 °C as the best overall performer. This work contributes through a sustainability analysis to the decision-making on which process configuration and conditions should be used, building on a previous technical analysis of a calcium looping for thermochemical energy storage process.