Opportunities and challenges of gas hydrate policies with consideration of environmental impacts

Gas hydrates are crystalline compounds formed by gas molecules captured inside a water framework, which are substantially stored beneath the seafloor and permafrost regions at a stable condition of high pressure and low temperature. It is suggested as a potentially alternative form of energy, of which the reserves are even larger than the gross reserves of all the proved conventional fossil fuels incorporating coal, oil and natural gas. Intense research activities throughout the world are focusing on the exploration and exploitation of these enormous energy resources. However, changes of hydrate volumes and morphologies during exploitation and the resulting weakening of the sediment mechanical strength may likely trigger catastrophic seafloor instability. Besides, the permafrost ablation experienced in the Arctic could also induce potential methane gas released from the hydrates into the atmosphere and most likely exert certain impacts on the climate change. To date, most researches focus on the technical solutions to the total resource estimation, reservoir exploration, mining technologies, and physical properties of hydrate sediments. Yet, limited documents are found to illuminate the worldwide efforts on national policies proposed to promote the secure and efficient utilisation of this source of energy. Herein, the special attentions are placed on the opportunities and challenges of gas hydrate policies with consideration of environmental impacts to push forward the global developments of the renewable and sustainable energy resources.