Research into clean electricity generation

Current research into a physical phenomenon discovered two centuries ago may hold the key to meeting future energy demands and reducing global warming.

The Seebeck effect involves the direct conversion of temperature differences into electricity.

It was first reported in 1821 by German-Estonian physicist, Thomas Johann Seebeck, who observed that a temperature difference between two ends of a metal bar created an electrical current in between, with the voltage being directly proportional to the temperature difference (the Seebeck differential).

Until now, the process has been deemed too inefficient and expensive for practical commercial applications.

However, new research has recorded the first measurements of the Seebeck effect in inexpensive organic molecules. The work is being done by mechanical engineer Arun Majumdar and chemical engineer Rachel Segalman, who both hold joint appointments at Lawrence Berkeley National Laboratory and the University of California at Berkley.

Majumdar and Segalman trapped electron-conducting organic molecules between a pair of gold electrodes, then measured the themopower (voltage) at room temperature with their own technique of scanning tunnelling microscopy.

Although the study was done on nanoscale materials, it cracks open the door to an entirely new field of thermoelectrics, which in turn could lead to a new generation of low-temperature solar cells and thin films, and low-cost plastic power generators.

Nearly all the world's electrical power "“ about 10 trillion watts "“ is generated by heat engines, giant gas- or steam-powered turbines that convert heat to mechanical energy, which in turn is converted to electricity.

In accordance with thermodynamics, however, much of the ehat isn't converted but released into the environment instead. To generate 10 trillion watts of electricity means wasting another 15 trillion watts as heat.

If even a small fraction of the lost heat could also be converted to electricity, its impact on the energy situation would be enormous. "We are talking about massive savings on fuel and atmospheric carbon dioxide," Majumdar said.