Methanol Economy - Methanol Economy Disadvantages

Methanol Economy Disadvantages

• High energy costs associated with generating hydrogen (when needed to synthesize methanol)
• Depending on the feedstock the generation in itself may be not clean
• Presently generated from syngas still dependent on fossil fuels (although in theory any energy source can be used).
• Energy density (by weight or volume) one half of that of gasoline and 24% less than ethanol
• Corrosive to some metals including aluminum, zinc and manganese. Parts of the engine fuel-intake systems are made from aluminum. Similar to ethanol, compatible material for fuel tanks, gasket and engine intake have to be used.
• As with similarly corrosive and hydrophilic ethanol, existing pipelines designed for petroleum products cannot handle methanol. Thus methanol requires shipment at higher energy cost in trucks and trains, until a whole new pipeline infrastructure can be built.
• Methanol, as an alcohol, increases the permeability of some plastics to fuel vapors (e.g. high-density polyethylene). This property of methanol has the possibility of increasing emissions of volatile organic compounds (VOCs) from fuel, which contributes to increased tropospheric ozone and possibly human exposure.
• Low volatility in cold weather: pure methanol-fueled engines can be difficult to start, and they run inefficiently until warmed up. This is why a mixture containing 85% methanol and 15% gasoline called M85 is generally used in ICEs. The gasoline allows the engine to start even at lower temperatures.
• Methanol is generally considered toxic. Methanol is in fact toxic and eventually lethal when ingested in larger amounts (30 to 100 mL). But so are most motor fuels, including gasoline (120 to 300 mL) and diesel fuel. Gasoline also contains many compounds known to be carcinogenic (e.g. benzene). Methanol is not a carcinogen, nor does it contain any carcinogens. However, methanol may be metabolized in the body to formaldehyde, which is both toxic and carcinogenic. Methanol occurs naturally in small quantities in the human body and in edible fruits.
• Methanol is a liquid: this creates a greater fire risk compared to hydrogen in open spaces. Methanol leaks do not dissipate. A methanol-based fire burns invisibly unlike gasoline. Compared to gasoline, however, methanol is much safer. It is more difficult to ignite and releases less heat when it burns. Methanol fires can be extinguished with plain water, whereas gasoline floats on water and continues to burn. The EPA has estimated that switching fuels from gasoline to methanol would reduce the incidence of fuel related fires by 90%.
• Methanol accidentally released from leaking underground fuel storage tanks may undergo relatively rapid groundwater transport and contaminate well water, although this risk has not been thoroughly studied. The history of the fuel additive methyl t-butyl ether (MTBE) as a groundwater contaminant has highlighted the importance of assessing the potential impacts of fuel and fuel additives on multiple environmental media. An accidental release of methanol in the environment would, however, cause much less damage than a comparable gasoline or crude oil spill. Unlike these fuels, methanol, being totally soluble in water, would be rapidly diluted to a concentration low enough for microorganism to start biodegradation. Methanol is in fact used for denitrification in water treatment plant as a nutrient for bacteria.