Could methanol be at the center of a cleaner, greener future infrastructure? (Image: Rex Features)

For years many companies, governments and researchers have predicted that our energy future must lie with the universe’s simplest element. The mooted hydrogen economy would use the gas to store and transport renewable or low-carbon energy, and power fuel cells in the transport sector or in portable electronics.

But creating the necessary society-wide infrastructure has proved difficult and expensive to get off the ground. And now a rival idea, first suggested in 2006 by Nobel chemistry laureate George Olah at the University of Southern California, has received a boost.

The methanol economy, say its supporters, could be with us much sooner than the hydrogen one.


Hydrogen dangers

Olah’s rationale is that modifying our existing oil and petrol-focused infrastructure to run on methanol will be much easier than refitting the world’s liquid-fuel-based economy to deal with an explosive gas.

Methanol has already been used to power portable gadgets and could potentially power vehicles and other devices. Now US chemists have worked out the conditions needed to make the feedstock for methanol production using renewable energy.

The research is significant because just as the lack of an efficient way to generate and store hydrogen is a major barrier to the idea of running civilisation on it, sourcing methanol on a vast scale is a similarly major hurdle.

Clean solution

The best way to make methanol is by steam reforming methane, produced when syngas – a mixture of hydrogen and carbon monoxide – is turned into liquid hydrocarbons via reactions such as the Fischer-Tropsch process.

The process is used today to make diesel and other liquid fuels from coal, and kept South African cars going during the country’s international isolation in the 1980s and 90s.

However, the whole point of the methanol economy would be to create a greener society, so any syngas must come from an environmentally friendly source, not fossil fuels.

Now chemist Scott Barnett at Northwestern University in Evanston, Illinois, and colleagues have shown that a solid oxide electrolysis cell, more normally used to split water into hydrogen and oxygen, could be that source.

Viable brew

Using a mix of one part CO 2 , one part hydrogen and two parts water in the device generates syngas at a rate which compares favourably with the processes used to make it from natural gas, says Barnett. At peak conditions of 800 °C and 1.3 volts, the system can produce 7 standard cubic centimetres of syngas per minute for every square centimetre of the electrolysis cell’s surface.

The next stage, turning the syngas into methanol, is a standard industrial reaction that is well understood.

Barnett’s method requires a steady stream of water vapour and CO 2 , but both gases are released when the methanol is used in fuel cells, and could be captured and re-used, he says.

That would add to the costs involved, but a hydrogen economy would require similar gas-capture technology, says Barnett, because hydrogen production requires a plentiful source of fresh water, which is heavy to cart about.

Olah thinks Barnett’s study is a useful one. “This [methanol economy] approach is now starting to be implemented around the world,” he says. “New methanol plants are being built in China, South Korea, Japan and Iceland.”

Limited scope

But others remain sceptical that methanol will ever occupy more than a small niche. There are several well-known problems with the use of methanol. Like hydrogen, and unlike petrol, methanol is not a source of energy, but simply an energy store, points out Ulf Bossel at the European Fuel Cell Forum in Oberrohrdorf, Switzerland. “The energy carried by methanol is less than was needed to make it,” he adds.

Barnett agrees that methanol is a poor substitute for using the power from a renewable generator like a wind turbine directly. But he says that in cases where direct use is not possible, liquid methanol beats the efficiency of hydrogen for storage and transportation.

Methanol could be used to store energy from renewable sources that often produce more electricity than is needed at a particular time, he says, and could also be useful at off-grid sites.

In these situations, Bossel agrees a modest methanol economy makes sense. “The hydrogen idea is gradually fading,” he says. “Methanol could be a better solution because it is easier to handle.”

Journal reference: Energy and Fuels (DOI: 10.1021/ef900111f)