The gain is made through avoided CO 2 emissions. The overall efficiency of the present cycle is defined as the energy output of the cycle divided by the accumulated energy of each of the production steps, in MJ per kilogram of methanol. Estimates of energy required for each separate process step. Energy in MJ per kg methanol. It should be noted that oxygen would be an important by- product of this process, valuable for other industrial processes.
Transport is undertaken at environmental temperature and pressure in a normal marine tanker.
The use of hydrogen for this step ensures that no further CO 2 is emitted for the required energy. Once emplaced the carbon dioxide will slowly react with the surrounding pore water to form a solid clathrate. Economic cost assessment . Turning now to the cost estimates for the proposed cycle. The figure shows that the costs of each option for each step are similar except for the transport step for liquid hydrogen and the solidification and disposal step for carbon dioxide.