Using the surrogate model developed for LCOM, optimisations are run for finding the settings providing the lowest LCOM within the bounds of the independent variables. Both USD, a significant reduction of 13%. This clearly display the benefit of performing such multi-parameter optimisation. Optimisations are performed for all responses with the corresponding trained surrogate models i.e. CAPEX, OPEX, Power and methanol production in addition to the levelised cost. The results are summarised in Table . As seen from the results, most optimisation targets favor operating pressure in the lower end of the investigated range, except when methanol production is being maximised. Also in terms of optimal temperature, the maximum methanol production appears to favor a temperature slightly higher than for the other optimisation targets. The purge rate is at its minumum value for both minimal LCOM and maximum methanol production. In the calculation of LCOM, the methanol production is a strong factor (denominator), hence the similarity. For the other targets, CAPEX, Power and OPEX, the purge rate is high which leads to lower compression power and therefore also to reduced CAPEX (smaller compressors installed), and also the derived effect of both lower fixed OPEX (due to lower CAPEX) as well as lower variable OPEX due to lower power consumption. The minimum OPEX and Power is obtained when the operating pressure is the lowest, which is due to lower CAPEX for equipment at lower design pressure. The lowest power case has the highest reactor/catalyst bed volume, since this leads to lower pressure drop for a fixed reactor length, and higher conversion and hence lower compression for the reduced recycle. Compared to the case of methanol production from syngas, optimality is generally obtained at lower operating pressure, higher reactor bed volume, slightly lower reactor temperature and significantly reduced purge rate.