05-15-2007

LET'S CHEMICALLY RECYCLE CO2 -- JUST LIKE PLANTS DO
METHANOL WOULD PROVIDE RENEWABLE FUELS, SYNTHETIC HYDROCARBON PRODUCTS WHILE STEMMING GLOBAL WARMING

George Olah, a professor of chemistry at the University of Southern California, was awarded the Nobel Prize for Chemistry in 1994. His most recent book, written with Alain Goeppert and G.K. Surya Prakash, is "Beyond Oil and Gas: The Methanol Economy."

By George Olah

LOS ANGELES -- Our early ancestors discovered fire and burned wood. The industrial revolution was fueled by coal. The 20th century added oil and natural gas to the mix.

When such fossil fuels are burned to generate electricity, to heat our houses or propel our cars and airplanes, they release carbon dioxide (CO2) and water (H2O). Fossil fuels are thus used up and are non-renewable on the human time scale.

The scientific challenge is to reverse this process by making hydrocarbon fuels and products by chemically recycling spent CO2 into a convenient fuel called methanol, either by catalytic reduction with hydrogen or by electrochemical reduction in water.

This process would, in effect, mimic the natural process of photosynthesis, which, using the energy of the sun, recycles CO2 and water into new plant life. But it would produce new hydrocarbon sources on the short human time scale, since plant life becomes a fossil fuel only over hundreds of millions of years.

The “methanol economy” made possible by this process can decrease and eventually liberate humankind from its dependence on diminishing oil, natural gas and coal reserves while mitigating global warming caused by their excessive combustion-producing CO2, a harmful greenhouse gas.

Methanol is an excellent fuel for transportation using the internal combustion engine. It is also an adequate fuel for fuel cells, which are capable of producing energy in reaction with atmospheric oxygen (air).

Unlike difficult-to-handle and explosive hydrogen gas, methanol can readily be stored and transported.

Methanol produced on a large scale will be also able to replace oil and natural gas both as a fuel and as raw material to produce synthetic hydrocarbon and their products (such as plastics) to which we are so accustomed in our everyday life.

For now, methanol can be efficiently produced from still-existing sources of natural gas or coal. New approaches now in development would allow chemical recycling of CO2 from the exhaust gases of fossil-fuel-burning power plants and other industrial or natural sources.

The emissions of fossil-fuel-burning power plants and chemical plants contain high concentrations of readily isolable carbon dioxide.

Because the large amounts of CO2 released into the atmosphere contribute greatly to global warming, it is now generally agreed that it must be captured and stored through the presently proposed process called sequestration.

But rather than simply sequestering CO2, chemical recycling would seem a more innovative approach. Water can provide the required hydrogen for converting CO2 to methanol using any energy source, including nuclear, photochemical or even bacterial conversions.

Eventually, atmospheric CO2 itself can be recycled, using catalytic or electrochemical processes; laboratory methods already have been successfully developed to do this.

I am optimistic for the future. Humankind is an ingenious species, which always seems to find ways of overcoming adversities and challenges. In the coming decades we must face the fact that our nature-given non-renewable fossil fuel resources are finite and diminishing while both our population and consumption are growing.

If we wish to continue living at a comparable or even higher standard of living as we do today while not further endangering our environment, we need to develop essential new solutions starting now.

Regulations and energy savings, however sensible they may be, cannot solve our problems on their own.

Certainly, we can extend our oil and gas reserves through more economical use with conservation and fuel-efficient technologies, particularly in the transportation sector (hybrid engines, fuel cells).

In reality, mankind will have to rely on all possible solutions available. By replacing the “petroleum economy,” the “methanol economy” holds great promise for the future. After all, the inescapable reality is that we live in a carbon-based global environment. 

Nature has shown us its own way to sustain itself in that environment by recycling CO2 into new plant life.

Human activities, however, increasingly seem to adversely affect nature’s own way. Scientific advance now allows us to do the opposite: supplement nature with humankind’s own alternative.

(c) 2007 Nobel Laureates Plus
Distributed by Tribune Media ServiceS, INC. (5/15/07)