Ethanol from carbon dioxide

Ethanol is a fuel that has come into its own as an additive to conventional fuel, or as a “drop-in” fuel substitute.

Ethanol is a fuel that has come into its own as an additive to conventional fuel, or as a “drop-in” fuel substitute.

Typical production of ethanol is provided by the fermentation and distillation of organic matter, cereal grain usually.

Ethanol has been available in blended fuels for a long time with major oil companies using it to increase the octane rating of their products, to prevent fuel line freeze-up in our cold climate and, notably, reduce emissions.

Advances in internal combustion engine technology, from pistons to turbines, have proven the viability of pure ethanol as a fuel.

As an alternate fuel, it flies in the face of agriculture as the acreage required for the creation of ethanol undermines the prime mandate of food production.

Alternate methods of producing ethanol using non-food material from marginal land or recycled materials are being explored with some success. Although viable, the input costs and production processes are not proving to be immediately cost-effective.

Carbon capture has been touted as a necessary pursuit in reducing greenhouse gases and, accordingly, carbon recycling is proving to be a fuel source.

Using carbon dioxide (CO2) or carbon monoxide (CO), to produce liquid fuels for the operation of contemporary machines, the carbon loop could be closed.

Interestingly enough, one such fuel currently being produced in carbon capture and utilization is ethanol.

Cost has always raised its many-horned head whenever alternatives are developed and tends to shackle research trying to grasp commercialization.

Innovation, however, has proven to be an indomitable force; when faced with one challenge, it tends to rise up and look for another way.

Engaged in this task, two scientists from Stanford University, assistant professor Matthew Kanan and graduate student Christina Li, have devised an ingenious copper cathode for the electrocatalysis of carbon monoxide-saturated water into ethanol. Normal copper, as with most electrode materials, is unsuitable for this task, with the end result invariably being hydrogen and oxygen gas.

The two researchers recognized the problem and developed a method for creating the copper-based electrode from “oxide derived copper.” When the cathode is manufactured, a nanocrystal lattice is produced, providing the mechanism for ethanol production. Experiments in their lab verified they were able to produce ethanol by running a very low 0.25 to 0.5 volts through the apparatus at normal temperature and pressure. Ethanol, acetate and n-propanol — all three constituents were produced at a very impressive 57 per cent Faraday efficiency.

When you take into consideration that some 800 gallons of water and a bushel of corn are required to produce three gallons of ethanol using the conventional fermentation distillation process, this discovery bodes well for producing a fuel that will allow the continued use of powered vehicles for transportation without any change to infrastructure.

If the whole process is driven by solar, water or wind sources, and if the carbon dioxide used to derive the carbon monoxide is captured from the atmosphere or the exhaust stream of industrial processes, conceivable we could close the carbon loop.

Lorne Oja is an energy consultant, power engineer and a partner in a company that installs solar panels, wind turbines and energy control products in Central Alberta. He built his first off-grid home in 2003. His column appears every second Friday in the Advocate. Contact him at: lorne@solartechnical.ca.