The invention relates to a method and apparatus for partially solidifying a methane comprising stream. The method comprisesproviding a liquid methane comprising stream (30) at a first pressure (P1),passing the liquid methane comprising stream (30) to a slush vessel (300) which is kept at a second pressure (P2), the second pressure (P2) being lower than the first pressure (P1), thereby cooling and at least partially solidifying the methane comprising stream (30) generating a methane comprising slush, andcollecting the methane comprising slush.

A CO.sub.2 energy storage system includes a storage tank that stores a CO.sub.2 slurry, including dry ice and liquid CO.sub.2, at CO.sub.2 triple point temperature and pressure conditions. The storage system also includes a first pump coupled in flow communication with the storage tank. The first pump is configured to receive the CO.sub.2 slurry from the storage tank and to increase a pressure of the CO.sub.2 slurry to a pressure above the CO.sub.2 triple point pressure. The energy storage system further includes a contactor coupled in flow communication with the first pump. The contactor is configured to receive the high pressure CO.sub.2 slurry from the pump and to receive a first flow of gaseous CO.sub.2 at a pressure above the CO.sub.2 triple point pressure. The gaseous CO.sub.2 is contacted and then condensed by the melting dry ice in the slurry to generate liquid CO.sub.2

A method and system of storing and transporting gases comprising mixing the gases with liquid natural gas to form a mixture. The mixture is a liquid-liquid mixture or slurry, and is stored in vessel configured for maintaining the mixture at a first location. The mixture is transported to a second location for storage in vessel for maintaining the mixture. The mixture is removed from the second location storage vessel for separation and use in additional processes.