Stealing Electricity From Algae

March 28, 2010— -- Why spend the time and expense necessary to harvest energy when you can simply steal it?

For the first time, scientists from California and Korea have successfully stolen an electric current from algae. The research could eventually create a new and environmentally friendly way to generate electricity.

"We have shown that we can steal an electrical current from algae," said Fritz Prinz, a scientist from Stanford University and co-author of the ACS Nano Letters article.

Creatures have been stealing energy from plants and algae for nearly as long as plants and algae have been around. Usually they steal the chemical energy, stored as sugar, starch and other molecules.

In the scientists' case, they stole electrons from a widespread and well studied algae called Chlamydomonas reinhardtii. To be able to extract energy from the algae, the scientists must first essentially jump-start the cells by applying what's called an over voltage, a tiny current of electricity that zaps the cell into action.

Voltage Only Works When Algae Exposed to Sunlight

The over voltage only works when the algae are exposed to sunlight. If the algae cells are zapped in the dark, they will not produce any current. When zapped and exposed to light, however, the electricity flows.

The amount of current harvested from the algae is tiny -- far too little to power any consumer electrical device. To get even one amp, the scientists would have to hook up trillions of cells, said Prinz.

That would take far too long, since the process reduces the algae's lifespan down to tens of minutes. Furthermore, the amount of current harvested does not exceed the amount of current necessary to jump start the algae into producing energy; there was no net gain in energy from the experiment.

However, algae are tiny, cheap and plentiful. Even so, it would take millions, probably billions, of electrified algae to power a commercial device. Such a setup is not practical at this time, nor will it be for many years, said Prinz.

Gary Brudvig, a scientist at Yale University, agrees with Prinz that a commercial device powered by stolen electrical current from algae is impractical. Still, the fact that Prinz and his colleagues stole any electrical current at all was impressive and opens new research opportunities.

"This paves the way to imagine using algal cells in some new kind of solar energy conversion process," said Brudvig, "that diverts what nature does into a way that could be used more directly than growing and harvesting a crop."