Green H2 derivative: CH3OH
Methanol (MeOH) is a promising alternative carrier for hydrogen. In liquid form under ambient conditions, it can be handled and distributed with exactly the same type of infrastructure thru which petrol is distributed today. Around 98 million tons (Mt) are produced per year, nearly all of which is produced from fossil fuels (either natural gas or coal) [IRENA, 2021].
The simplest alcohol w/ the lowest carbon content, methanol (a.k.a. "wood alcohol") is used as a precursor to other industrial chemicals, such as methyl benzoate, formaldehyde, methyl tertiary-butyl ether (MTBE - gasoline additive that reduces tailpipe air emissions), acetic acid, and also paints, cosmetics, and plastics. Figure 1 shows worldwide methanol application.
Figure 1: % of the worldwide methanol conversion
Methanol is an excellent hydrogen carrier fuel, packing more hydrogen in its simple alcohol molecule than can be found in hydrogen that's been compressed (350-700 bar) or liquefied (-253˚C). It can be used as raw material for synthetic hydrocarbons: for example, thru the methanol-to-gasoline (MTG) process, it is transformed into gasoline. In addition, it can be “reformed” on-site at a fueling station to generate hydrogen for fuel cell vehicles.
Global production & main producers
Production of methanol across the globe has been on a continual annual increase during the last few years. In 2022, methanol production is estimated to reach over 111 million tons [STAT, 2023]. China is the world's leading producer of methanol, followed by the U.S., Iran, Saudi Arabia, and Indonesia [EIA, 2017]. Similar to how ethanol is currently blended into motor gasoline in the U. S. and Brazil, methanol is blended into gasoline in China [IB, 2023].
Fuel for ships
Methanol has the advantage that it is similar to traditional fuels: it is a hydrocarbon and a liquid, which makes it easier to allow dual-fuel engines that can run traditional fuels or methanol. Such dual-fuel engines already exist in ships today [FW, 2023].
Methanol molecule can be made from conventional fossil sources & emerging renewable feedstocks. Methanol is produced by reacting CO2 & hydrogen (CO2 + 3H2 → CH3OH + H2O). Figure 2 shows conventional methanol production process.
A transition to renewable methanol (from biomass or synthesized from green H2 & CO2) could expand methanol’s use as a chemical feedstock & fuel while moving industrial & transport sectors toward net carbon neutral goals [IRENA, 2021]. Renewable methanol (or bio-methanol) can be produced from carbon dioxide & hydrogen ontained from renewable electricity, as shown in Figure 3.
Compared to conventional fuels, renewable methanol cuts carbon dioxide emissions by up to 95%, reduces nitrogen oxide emissions by up to 80%, and completely eliminates sulfur oxide and particulate matter emissions [MI, 2023]. The methanol produced by either route is chemically identical to methanol produced from fossil fuel sources.
Figure 2: Methanol production (conventional process)
Figure 3: Renewable methanol production process