Green Power: Reasearchers Harness Algae to Generate Electricity

Last Updated Apr 20, 2010 6:34 PM EDT

One of the longest-running promises in alternative energy is that someday, humble algae will fuel our cars, trucks and planes. Algae make a lot of oil when they're eating up sunlight and the nutrients in water, so for decades researchers have tried to convert that oil into an economical fuel.

The short story is that it hasn't worked. You could fill up your car from algae today, but the cheapest algal biofuel is over $30 per gallon. So some researchers have moved on to an even more bizarre idea: hooking up algae to wires to directly steal their electrons, like tiny Frankenstein dynamos.

Stanford University scientists used a gold nanoelectrode to pierce the algal cell wall, which then closed around the electrode without visible damage. As the algae cell performed photosynthesis, the gold wire channeled the energy outside of the cell, where the scientists were able to gather it -- although a single cell produced only a picoampere, or enough to power approximately nothing. You'd need a trillion times that amount to charge a AA battery.

If this sounds like a fantastically tricky operation with no real-world benefit, you'd be half-right. The idea that we might be able to profitably insert wires in individual algae cells to milk their electrons when we can't eve gather and use their oil economically seems like scientific hubris.

But there's also a beautiful logic to the idea. Each cell already works like a little solar panel: as sunlight hits the algae, photosynthesis draws electrons through the cell to convert the incoming energy to a usable form like sugar and oil. The nanoelectrode simply pulls the electrons all the way through the cell and out to be used.

In any energy conversion, some of the energy is lost. Taking electrons directly from the cells could provide the improvement necessary to finally turn algae into a viable source of energy. The idea becomes especially exciting when considering how groups of algae cells could create a living, growing solar panel, one that is actually removes carbon from the air as it provides electricity.

This isn't the first time that researchers have considered using algae for solar, either. An experiment at Oregon State University last year tried to demonstrate that diatoms, a type of algae, could be used in manufacturing solar panels -- although in that case, the algae would not survive the process. Either that idea or Stanford's technology is theoretically capable of exceeding the efficiency of existing solar panels.

On the other hand, the new promise of algal solar cells only pushes the horizon further out for algae research. Even if genetic engineering techniques can create algae naturally adapted to providing power, the lengthy development times for a new technology like this -- typically, 10 to 20 years -- means that algae still runs the risk of being left in technology's history books, while more usable technology speeds ahead. As Kermit the Frog once pointed out: It's not easy being green.

[Image credit: ingridtaylar / Flickr]