I can imagine several circular systems using this technology.

Using corncob waste as a starting material, researchers have created carbon briquettes with complex nanopores capable of storing natural gas at an unprecedented density of 180 times their own volume and at one seventh the pressure of conventional natural gas tanks. . .

The briquettes are the first technology to meet the 180 to 1 storage to volume target set by the U.S. Department of Energy in 2000 . . .

Standard natural gas storage systems use high-pressure natural gas that has been compressed to a pressure of 3600 pounds per square inch and bulky tanks that can take up the space of an entire car trunk. The carbon briquettes contain networks of pores and channels that can hold methane at a high density without the cost of extreme compression, ultimately storing the fuel at a pressure of only 500 pounds per square inch, the pressure found in natural gas pipelines.

The low pressure of 500 pounds per square inch is central for crafting the tank into any desired shape, so ultimately, fuel storage tanks could be thin-walled, slim, rectangular structures affixed to the underside of the car, not taking up room in the vehicle. . .

In addition to efforts to commercialize the technology, the researchers are now focusing on the next generation briquette, one that will store more natural gas and cost less to produce. Pfeifer believes this next generation of briquette might even hold promise for storing hydrogen.

It isn't clear that corn cobs are necessary for the technology, they're just a handy source of carbon for the folks in KC and surrounds, but it rings some extra bells.

Using methane for fuel has some advantages. It's not only clean burning compared to other fuels, it can be produced easily from organic wastes. Indeed, it's difficult to prevent methane production as organics rot. When the rotting is done in confinement in a digester - a common and fairly well developed technology - it's easy to capture the methane. A valuable coproduct of the process is compost suitable for soil amendment.