Clathrate hydrates are well known structures that were considered for many years as harmful by the oil and gas industry because of their annoying tendency to plug pipelines. However, hydrates are now attracting renewed interest in many fields. Indeed, gas hydrates naturally found in deep seas and permafrost may provide a large amount of methane. Other positive applications include carbon dioxide sequestration, separation and natural gas storage and transportation. Finally, the use of their dissociation energy can be applied in refrigeration processes and cool storage.