If you lived in Alaska, the natural gas that you would be able to keep in an outdoor storage tank in winter would be methane. The melting point of methane is -183ºC, while the boiling point is -164ºC. These temperatures are much lower than the average temperatures of Alaska (the lowest temperature ever recorded in Anchorage was −38.9 °C).
The gas that you could keep in an outdoor storage tank in winter in Alaska is Methane.
The reason is the extreme low temperature during the winter. The boiling point of butane is 44 ºF ( -1ºC) and that of propane is a higher -43.6 º F but still within the range of average minimum winter temperature in Alaska (-50 ªF). Therefore we will have condensation in the tanks and not enough gas pressure.
Methane having a boling point of -259 ºF will not condense at the low wintertime temperatures in Alaska.
