Singaporean researchers store methanol in ice

In Singapore, natural gas is mostly stored under high pressure or cooled into liquid at -162 °C — both methods that are energy-intensive and costly. An alternative approach, called solidified natural gas, locks methane inside an ice-like cage known as a hydrate. But in practice, these hydrates usually form far too slowly to be practical on a larger scale.

Researchers at the College of Design and Engineering, National University of Singapore, have found a simple workaround by adding amino acids — the building blocks of proteins. In a new study ‘Rapid conversion of amino acid modified-ice to methane hydrate for sustainable energy storage’ published in Nature Communications, the researchers showed that freezing water with a small amount of these naturally occurring compounds produces an “amino-acid-modified ice” that locks in methane gas in minutes. In tests, the material reached 90 per cent of its storage capacity in just over two minutes, compared with hours for conventional systems.

The method also brings environmental benefits. Because amino acids are biodegradable, the method averts the environmental risks posed by surfactants often used to speed up hydrate formation. It also allows methane to be released on demand with gentle heating, after which the ice can be refrozen and reused, creating a closed-loop storage cycle. This combination of performance and sustainability makes the approach attractive for large-scale natural gas storage as well as for smaller, renewable sources of biomethane. The team also sees potential for adapting the technique to store other gas, including carbon dioxide and hydrogen.