Given that this process does not involve any catalyst in it, which saves the costs of the catalyst. However, the process itself might be energy intensive which can add costs on the energy input.
If I have an answer to your question, i would not disclose it publicly. The answer is potentially patentable. If you want to discuss your question, you need to provide a detailed analysis of the process. In this case you may have a feedback
It makes no sense to convert methanol into diesel fuel because methanol is normally made from synthesis gas. And diesel production from synthesis gas is a well known process.