Here's another report of the new bioRefinery project in Iowa that will produce ammonia.

Natural gas is used to make ammonia, the basic component for nitrogen fertilizer. Prices for natural gas rose dramatically in the U.S. over the past 10 years, according to the U.S. Department of Agriculture. Because natural gas is cheaper in other countries, the U.S. has increasingly turned to foreign supplies for ammonia since 1990.

"We don't relish being in Ukraine's shoes," Oswald said, referring to Russia's embargo on natural gas supplies to its neighbor during the winter.

The cost of natural gas now accounts for up to 90 percent of the cost of making nitrogen fertilizer, according to the U.S. Government Accountability Office.

It's worth noting that it is the hydrogen in methane (CH4, natural gas) that is of value for making fertilizers. Natural gas has no nitrogen in it, that comes from the air around us which is mostly non-reactive nitrogen gas, N2.

SynGest says its system for making fertilizer also reduces the heat-trapping gases stored in the atmosphere. Corncobs are from plants that consumed carbon dioxide as they grew, and the gasification process needed to make the ammonia leaves behind a black residue, called biochar, that can be added back to the fields to improve the soil. Biochar also stores carbon dioxide.

It's worth noting that any biomass will serve for this purpose. There is nothing unique about corn stover or cobs, it's just what they have in that area. Also, biochar does not store carbon dioxide, it just stores the carbon with no oxygen. Over half the weight of carbon dioxide is in the two oxygen atoms, so sequestering a ton of biochar is worth more than 2 tons of carbon dioxide.

"If energy supplies in general become tight we can always turn down the thermostat and we can always carpool," Oswald said. "But when nitrogen fertilizer is missing or reduced in farming, crop production drops by a measurable amount. That directly affects the amount of food available, which is not replaceable. You can't just hitch a meal the way you can hitch a ride."

Dennis Harding, a former farmer who directs new business development for the Iowa Farm Bureau, said one of the most attractive parts of the SynGest plan is that it would set a more stable price for fertilizer.

"Over the last couple years grain prices went up but inputs went up as well because of changes in energy costs, and we had a lot of volatility," Harding said. "Sometimes volatility is the hardest thing to manage."

This is an important point. Being less subject to price fluctuations is a valuable thing and can command a premium price. A farmer will even pay more for an input if it is guaranteed to be available at that same price over time.

I've been writing about the sensibility of such systems for a long time. Ammonia is also a fuel. The image of a grower driving an ammonia fueled tractor to spread ammonia fertilizer in fields to grow crops that not only produce food and fiber but also produce more ammonia has a pleasing circularity. When we add that the carbon sucked from the air by those crops is also spread back on the fields in a durable form that accumulates over time and improves the soil in many ways, not least by reducing the need for ammonia, the system promises increasing returns or reduced costs, or both.

This would also be a better use for the methane produced by manure lagoons, landfills and anaerobic compost digesters. Just burning it for energy production seems wasteful when it could be used to create more biomass. Methane is also a transportation fuel, so a similar though lesser sort of circularity could be achieved in a biomass -> anaerobic digestion -> methane system. Compost isn't a durable form of carbon, so that benefit would be lost, but some small amount of humus is produced which is semi-durable.

I expect such systems to become more common as fossil fuels become more expensive. There's still a great deal of natural gas to be mined, but it isn't often near where it is needed and is subject to all manner of political gaming, all of which will drive prices higher and make availability unreliable.