Natural Gas Hydrates
Gas hydrates – natural gas and water frozen together into a solid substance – are common in arctic permafrost regions and in sediments in the ocean's deep waters. Research is now underway to better understand this vast, untapped resource: how natural gas hydrates form, where they are located and how they could be used as a future source of natural gas.
Estimates of the resource potential of natural gas hydrates vary, but most estimates place the resource potential as greater than the known reserves of all oil, natural gas and coal in the world. Several possible recovery methods are now under investigation:
- Heating the hydrates using hot water, steam, electromagnetic radiation (such as microwaves) or electricity. These methods would raise the temperature so that the hydrates would melt, releasing the natural gas.
- Lowering the pressure of the hydrates. Lowering the pressure would also cause the hydrates to melt, releasing the natural gas.
- Injecting chemical inhibitors. Inhibitors prevent hydrates from forming or cause hydrates that have formed to “melt.”
The success of any of these techniques will depend on their ability to overcome a number of inherent challenges:
- Hydrates are found in hostile environments such as deep oceans miles offshore, or in permafrost regions of the arctic.
- The hydrates are often dispersed over large areas and therefore may not be easily recovered.
- Hydrate formation is not well understood and the known location and concentration of hydrate deposits has not been adequately characterized.
Despite these challenges, the study of hydrates continues because of the potential they provide for meeting the world’s growing energy needs. Hydrates may also provide a novel way to store natural gas for transportation. Currently, natural gas travels primarily by pipeline. Solidified gas hydrates could be transported by specially designed ships, for example.
Hydrates may also be a way to store natural gas for use in natural gas vehicles. Currently, natural gas must be compressed and stored in cylinders in vehicles that run on natural gas.