Dirt Batteries

Cat DiStasio at Engadget has a reminder about other potentially exciting sources of renewable energy. I particularly liked the microbial "dirt batteries" developed at Harvard.

Scientists at Harvard University built a battery that's essentially powered by dirt. The creation of the microbial fuel cell (MFC) batteries is an energy storage breakthrough primed to aid residents of countries with absent or unstable power grids, such as regions of Africa where many people still live off the grid. MFC batteries are notoriously low in cost and can be constructed from local resources that look nothing like the batteries in your flashlight or cell phone.

Link: Six unexpected sources of renewable energy