Uncovering the secrets of fire ice
For obvious reasons, methane hydrates are sometimes called 'fire ice'. (image courtesy MethaneGasHydrates.org)
Methane hydrates are typically stored in regular ice crystal structures termed clathrates (also known as methane clathrate). The methane/ice compound is stable but as the ice melts the methane is released, leading to its other name of ‘fire ice’.
Researchers at the Advanced Institute of Science and Technology in Korea along with collaborators at local Universities have found that under certain conditions the methane molecules can be displaced by CO2, yielding natural gas which can be used for energy and trapping CO2. The work was originally published in the Proceedings of the National Academy of Sciences in 2006, and has yielded over 137 citations. A group at UC Berkeley has reviewed the engineering implications to find that such a process is feasible and because of the revenue generated by the sale of gas, could be deployed without significant government support.
Storing carbon in methane clathrates is at a very early stage but includes some promising features. Unlike geological storage gas exchange in clathrates is actually better in the presence of nitrogen, potentially eliminating the need for the most expensive gas separation steps involved in current capture processes. Also, geological storage requires limited storage reservoirs, but as natural clathrates are widespread and artificial clathrates can be created, there is a theoretically almost unlimited capacity to store CO2.
What does this mean for Cleanleap countries?
Seafloor methane hydrates have the potential to cause catastrophic issues. Fortunately it looks like this won’t be an issue, but if it does it will be at a global level.
In terms of investigating methane hydrates as an energy source, developing nations are also making significant investigative efforts. India is leading the way – having discovered huge offshore gas hydrate deposits - about 26 trillion cubic metres, according to Krishna Vishwanath, NGHP’s chief geologist. That’s roughly enough to fill one billion Olympic size swimming pools. China is also conducting investigations and making progress. Overall Asia is leading the developing world in gas hydrate development. Africa and Latin America are interested, but less advanced with their investigations.
The whole area of utilising new sources of methane holds massive risks and issues. As we noted in our previous post, the release of methane from organic matter decomposition is a big issue for hydro but also presents opportunities. Particularly important is for the hundreds of new hydro projects being deployed by China around the world to explore how to capture tropical reservoir methane and use it to generate electricity - turning a problem into an asset. It certainly looks like the investigation and sharing of knowledge around mitigating the release of methane and using it as an energy source should be an important area of research for Cleanleap countries.