Carbon dioxide capture and storage (CCS) is a promising strategy to battle the climate change by injecting large-scale of carbon dioxide back to underground formations and storing the carbon dioxide possibly permanently. It is an existing technology but for climate and economic concern it is still a relevantly new concept. We are interested in studying the cost of CCS, in particular the cost of CO2 geological storage, and optimize the cost, since the high cost of CCS is a big hurdle for industry to deploy this technology.