Liquefying hydrogen requires chilling it to -253º C, significantly lower than LNG’s 161.5º C, a factor expected to add to both liquefaction and vessel costs. Moreover, liquefying natural gas consumes less than 10% of its energy, but this proportion increases to about a third for hydrogen. At 3.5 kWh/m3 hydrogen is less dense than natural gas (11.4 kWh/m3), so the same volume would contain far less energy, meaning that more carriers would be needed. This could make the cost of seaborne trade in hydrogen challenging to bear. Ammonia is corrosive and toxic, but has lower thermal insulation requirements than LNG and becomes liquid at only -33º C.