Electricity from Algae

Mike Thompson, a British designer working in the Netherlands, recently published the design for a solar-powered lamp, that uses water, CO2, and blue-green algae to charge a small battery, which then powers a small LED lamp when power is needed.

I was pretty excited when I saw the story cross my feed reader. In High School, I spent some time doing a bit of research on a similar battery, using blue-green algae and a purple chemical whose name I can not recall, which would strip the electrons from chloroplasts as they were excited by a proton of light. The reaction was stimulated by heat as well, you’d get a sharp rise in the current drawn from the reaction. However, the chemical had a saturation point, and after a while, it couldn’t draw any more electrons. We did some work to see if there was a way refresh the reaction, but got nowhere.

So, to see something that functions identical to work that I was doing a bit on over ten years ago, was pretty interesting.

Now, reading the PDF linked above, the mechanism for this is a lot more involved. It required inserting 30 nanometer wires into a chloroplast, it’s able to produce about 0.6 milliamps per square centimeter, not much, but if all it’s going to do is charge a battery to power a small lamp, then it doesn’t need to be much. Now, I don’t remember the exact output of the reaction that I was working on all those years ago, but I do remember it being more prolific, though immensely shorter lived.

However, once done, you have a system that requires you only add water and CO2. And, if you read the document, a large part of the reason behind this is to make people more cognizant of their energy usage by making the generation of that energy more personal.

I think this is a really interesting project, but I’m not sure it’s sustainable. Cory Doctorow in his new book, For The Win, several times makes the claim that all the gold ever mined on Earth, would create a block no larger than a regulation Tennis court, but that the certificates for gold sold amounted to roughly double that. Gold has value because it’s rare. It’s current value, according to Yahoo! Finance, is over $1200 per ounce.

Admittedly, the amount of gold in a 30 nanometer wire is miniscule, and if anything is going to be in the way of this process, it’s likely to be the difficulty of building this device than the cost of gold needed to build it. However, the general idea of making people more cognizant of their energy use decisions, is valuable, and I’m in favor of any research that focuses on energy generation in novel ways, and I think algae could be a really interesting source of electrical power if we can find an easier way to recover that energy. I’m not sure this method can be done at scale, but in a world where 2.6 Billion people still defecate openly; by streams, rivers, or lakes; generating energy on the small scale, to provide light into the evening, is certainly not going to hurt anyone.