Methanol economy
The methanol economy is a hypothetical future economy in which methanol has replaced fossil fuels as means of transportion of energy. It offers an alternative to the hydrogen economy and ethanol economy. Recently Nobel prize winner George A. Olah advocated the methanol economy in an Essay 1. He lists arguments against the hydrogen economy and discusses the generation of methanol from carbon dioxide or methane.
The disadvantages of hydrogen versus methanol are:
- high energy costs associated with generating hydrogen
- generation in itself not clean
- presently generated from syngas, still dependence on fossil fuels.
- hydrogen is volatile and explosive
- required infrastructure prohibitively expensive
- volumetric power density one third of that of gasoline
In the methanol economy methanol is generated:
- by carbon dioxide recycling with hydrogen or with water in an electrochemical process
- by oxidation of methane (present as as yet untapped methane clathates) with oxygen and a suitable catalyst
Methanol can be used directly as fuel or in a fuel cell for instance in a direct methanol fuel tank (DMFT).
Methanol economy advantages compared to hydrogen:
- efficient energy storage
- serves as a raw material for the chemical industry
- power density one half of that of gasoline
- can be blended with gasoline
- no large investment in infrastructure
- user friendly & safe.
Methanol economy disadvantages:
- methanol is toxic
- methanol is heavier than hydrogen; a safety risk in the event of leakage.
A source of carbon dioxide in a recycling process can be from the earth's atmosphere but given the low concentration (0.037%) it would require the development of an efficient semipermeable membrane technology. Other sources are the exhaust of fossil fuel power plants.
References
- [1] Beyond Oil and Gas: The Methanol Economy George A. Olah Angewandte Chemie International Edition Volume 44, Issue 18, Pages 2636-2639, 2005