Dog parks, as you know if you've ever been to one, create a lot of excrement. Now, Cambridge, Massachusetts recently implemented the ParkSpark Project, which is streetlight powered entirely by dog droppings.

It works simply: You put the dog poop into the large container, where it is digested by bacteria, creating methane gas, which can then be used to light a lamp. Biogas digesters like this are often used on landfills or for large amounts of cow manure, but it's unusual to see it on such a small, human scale.

This new street light both helps people connect their actions to the larger power system (poop in equals power out). But more importantly, it highlights the idea that there are potential energy sources all around us. If we're going to use much less oil, there isn't going to be a one-stop solution. It will be a combination of every available scrap of energy, from wind to solar to, yes, dog poop.

The lamp, a shining example of how humans can make use of an underutilized and perpetually renewable energy source -- feces -- is the brainchild of Matthew Mazzotta, a conceptual artist who studied at the nearby Massachusetts Institute of Technology (MIT) who wanted to give back to the community.

"No one is taking account of all the methane produced by animals that live in cities," Mazzotta told AOL News. "Methane is one of the most potent greenhouse gases -- even more than carbon dioxide -- but when it burns [it] separates into water and carbon dioxide.